Source: NORTH CAROLINA STATE UNIV submitted to NRP
WEED MANAGEMENT IN VEGETABLE AND SMALL FRUIT CROPS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
COMPLETE
Funding Source
HATCH
Reporting Frequency
Annual
Accession No.
1011077
Grant No.
(N/A)
Cumulative Award Amt.
(N/A)
Proposal No.
(N/A)
Multistate No.
(N/A)
Project Start Date
Oct 1, 2016
Project End Date
Sep 30, 2021
Grant Year
(N/A)
Program Code
[(N/A)]- (N/A)
Recipient Organization
NORTH CAROLINA STATE UNIV
(N/A)
RALEIGH,NC 27695
Performing Department
Horticultural Science
Non Technical Summary
Small fruit and vegetable crops are intensively managed crops with a limited number of herbicides registered for application. It is estimated that losses in production and revenue due to poor weed control averages at least 20 to 25% annually. For example, in a survey of North Carolina county Extension faculty, estimates of 60 to 70% of the North Carolina sweetpotato acreage experiences up to 30% yield and quality reduction resulting from pigweed, primarily Palmer amaranth (Amaranthus palmeri). Meyers et al. (2010) reported season long Palmer amaranth interference in 'Beauregard' and 'Covington' sweetpotato reduced total marketable sweetpotato yield 36 to 81% at densities of 0.5 to 6.5 plants/m of crop row. Other weeds are also reported to be troubles in vegetable crops. Season-long interference of yellow nutsedge (Cyperus esculentus) reduced tomato shoot biomass by 34% (Morales-Payan et al. 2003). Season-long presence of large crabgrass (Digitaria sanguinalis) at a density of 55 plants m-2 in direct seeded tomato caused 74% yield reduction (Monaco et al. 1981). Reduced marketable yield of fresh-market tomato was reported when 1 to 3 eastern black nightshade was growing per crop hole (Buckelew et al. 2006). Garvey et al. (2013) reported an approximate 70% marketable yield loss in fresh-market tomato with one palmer amaranth per crop hole. Similar results have been reported in other vegetable crops.The critical weed-free period is the time early in the crop season when weeds must be controlled to prevent any crop loss due to weeds (Oliver 1988). This period is variable and is dependent on crop, weed species, and production area. Limited research has been conducted determining the critical weed-free periods for small fruit and vegetable crops (Chaudhari et al. 2016; Friesen 1978; Garvey et al. 1998; Nersen 1989; Mallet and Ashley 1988; Monks and Schultheis 1998; Seem et al. 2003; Weaver 1984; Weaver et al. 1983). Generally in vegetable crops this time period is during the first 4 to 6 weeks after planting the crop (Chaudhari et al. 2016; Friesen 1978; Garvey et al. 1998; Nersen 1989; Mallet and Ashley 1988; Monks and Schultheis 1998; Seem et al. 2003).Palmer amaranth is the most problematic and competitive weed in many vegetable crops and focal point for development of weed management programs by growers. In sweetpotato, predicted marketable sweetpotato yield can be reduced by as much as 50% with as few as one Palmer amaranth plant per m-1 of crop row (Meyers et al. 2010). Controlling Palmer amaranth in sweetpotato is critical to prevent yield and quality loss of marketable sweetpotato storage roots. The goal of a weed control program for Palmer amaranth needs to be 100% control because of its reproductive capacity which can exceed 500,000 seeds per mature female plant (Keeley et al 1987; Webster and Grey 2015). In some instances the number of seeds can be in excess of 1,000,000 (A.C. York, personal communication). Palmer amaranth has the ability to rapidly infest fields and easily spread between fields. In addition, Palmer amaranth populations continue to develop that are resistance to a growing number of herbicide families, many of which are critical to the production of vegetable crops (ie sweetpotato).The high cost of hand labor and mechanical cultivation for weed control in small fruit and vegetable crops necessitate the use of herbicides. The lack of registered herbicides for these crops has always been a major obstacle to attaining optimum production of vegetable and small fruit crops. Herbicide development in vegetable and small fruit crops is now almost totally through the Interregional Research Project Number 4 (IR-4) because these crops are grown on fewer acres compared to agronomic crops. Fear of damage claims to high value vegetable and small fruit crops, low relative acreage of these crops, and the high cost of developing new herbicides discourage herbicide manufacturers from developing new small fruit and vegetable registrations for herbicides. The loss of methyl bromide has greatly reduced the ability of growers to control troublesome weeds in certain vegetable and fruit crops. Alternative strategies are not as effective as methyl bromide. Growers of these crops have historically relied heavily on methyl bromide for control of weeds. However with the loss of methyl bromide in relatively recent years, new herbicide registrations in these crops are necessary especially for hard to control weeds including yellow and purple nutsedge (Cyperus rotundus). Polyethylene mulch provides excellent broadleaf and grass control, however, nutsedge can pierce through the polyethylene mulches (Adcock et al. 2008, Culpepper 2014, Henson and Little 1969, Johnson and Mullinix 2008, Webster 2005). In North Carolina production systems yellow and purple nutsedge are troublesome weeds in cucurbit crops, tomato, and pepper (Webster 2010). Methyl bromide alternatives need to be developed for weed control in these vegetable crops.Cultivars within crops vary in their susceptibility to herbicides (Mullins et al. 1993, Jennings 2010, Robinson et al. 1993). Information developed in these studies has been used by agrochemical companies for developing their herbicide registrations and is used extensively by the national IR-4 program. Because of potential for herbicide injury to crop cultivars, tolerance of crop cultivars must be assessed for sensitivity to herbicides and methods developed that increase tolerance of crop cultivars to herbicides.The purpose of this research is to develop and evaluate weed management strategies, chemical and non-chemical methods, to manage weed issues in small fruit and vegetable crops.
Animal Health Component
60%
Research Effort Categories
Basic
20%
Applied
60%
Developmental
20%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
2131199114050%
2131499114050%
Knowledge Area
213 - Weeds Affecting Plants;

Subject Of Investigation
1499 - Vegetables, general/other; 1199 - Deciduous and small fruits, general/other;

Field Of Science
1140 - Weed science;
Goals / Objectives
The overall objective is to conduct research that will develop weed management programs for vegetable and small fruit crops. The following specific objectives will accomplish this overall objective.1) Weed biology/ecologya) Determine the critical weed-free period of specific weeds in certain vegetable and small fruit crops.2) Weed managementa) Conduct research that will identify herbicides that are safe to small fruit and vegetable crops.b) Develop systems that focus on control of specific problem weeds (i.e. resistant weeds, perennial weeds such as nutsedge, troublesome weeds, etc.).3) Carryover of herbicidesa) Determine carryover potential of herbicides applied in agronomic, vegetable, or small fruit crops into vegetable and small fruit crops for growers to utilize in making decisions regarding crop production and crop rotation systems.4) Application technologya) Determine plant spectral signatures through reflectance curves for weed species and sweetpotato using hyperspectral imaging.b) Determine the effect of Palmer amaranth and large crabgrass interference on spectral reflectance, yield and biomass of sweetpotato.
Project Methods
Objective 1: The critical weed-free period for some of North Carolina's major vegetable and small fruit crops (watermelon) will be determined using a conventional additive technique involving removal and plant back of weeds (Oliver 1988). The weeds included in these studies will be the most common and/or troublesome weeds. In the removal studies, weeds that emerge with the crop will be removed (chemically or by hand) at various times after emergence or transplanting, and then plots maintained weed-free for the rest of the season. In the plant back studies, weeds are allowed to emerge or are seeded at various times after emergence or transplanting. The experimental design will either be a randomized complete block or factorial on a randomized complete block. Treatments will be replicated 3 to 4 times. Data collected will include yield and quality, biomass and others. The environmental factors such as light, soil moisture and nutrients will be measured.Objective 2a: Studies will be conducted to determine tolerance of vegetable and small fruit crops to herbicides with a national registration and nonregistered herbicides that may be candidates for registration. Data collected will include visual injury, crop yield and quality. Experimental design will be a randomized complete block or a split plot. Treatments will be replicated 3 or 4 times.Objective 2b: Field experiments will be conducted in various small fruit and vegetable crops to determine the efficacy of potential herbicides to control the most troublesome weeds in these crops. The studies will be conducted on research stations and/or on-farm. Treatments will be randomized three to four times. Crop response (height, injury, stand etc.), weed control and yield (quantity and quality) will be recorded.Objective 3a: Field experiments will be established to determine the carryover potential of herbicides applied in agronomic, vegetable, or small fruit crops on vegetable and small fruit follow-crops. Plots will be maintained weed-free in both years through application of herbicides or by hand removal. Crop response and yield and quality will be measured.Objective 4a: Studies will be conducted to determine plant spectral signatures through reflectance curves for Palmer amaranth, common ragweed (Ambrosia artemisiifolia), yellow nutsedge and large crabgrass (Digitaria sanguinalis) and sweetpotato using hyperspectral imaging. Each weed and crop species will be seeded in pots and thinned to one plant per pot. Pots will be placed outdoors and maintained for 60 days after crop emergence. Data collected will include hyperspectral measurements using DARWin SP utilizing a PSM 2500 Spectroradiometer. Individual leaf measurements (5 from the upper portion of the canopy and 5 from the lower portion of the canopy due to spectral variability between portions of the plant will be taken using a hyperspectral sensor with leaf clip containing an independent tungsten light source. In addition, 5 canopy measurements using a hyperspectral sensor (350 to 2500 nm) between the hours of 10 am and 2 pm will be taken using ambient sunlight. A standard color (RGB) reference image will also be collected at the time of each hyperspectral measurement. Measurements will be taken weekly.Objective 4b: Studies will be conducted to determine the effect of Palmer amaranth and large crabgrass interference on spectral reflectance, yield and biomass of sweetpotato. Treatments will include large crabgrass at 0, 1, 2, 4, and 16 plants per m of row and Palmer amaranth at 0, 1, 2, 4, and 8 plants per m of row. Weed only (no crop) at four densities and a bare ground (no crop or weed) will be included as control plots. Hyperspectral data will be collected. Five canopy measurements per plot will be collected using a hyperspectral sensor. Soil water availability will be measured weekly at time of data collection. Plants will be harvested and dried to determine crop and weed biomass. At harvest sweetpotato will be separated into marketable grades (canner, number 1, and jumbo) to determine yield.Evaluation plans may include the following metrics.An advisory committee will be formed consisting of growers and other stakeholders to offer input on objectives and methods and to evaluate outcomes.To determine the application of critical weed-free periods developed, data from growers can be collected to determine if there has been a change in knowledge.To demonstrate the development of new herbicides for vegetable and small fruit crops data can be collected from IR-4 for registrations granted during the project period.To demonstrate progress towards developing new weed management plans data can be collected regarding growers' adoption of the new management plans.

Progress 10/01/19 to 09/30/20

Outputs
Target Audience:Vegetable and small fruit growers, commodity groups, extension agents, agrochemical company personnel, faculty at other institutions, and other people in the agricultural community. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Graduate students (MS and PhD) were trained in weed science research including weed biology and weed control strategies. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Field research studies were conducted to determine the effect of tillage system on Palmer amaranth control and sweetpotato growth and yield and quality. Field studies were conducted to determine the effect of 2,4-D choline on strawberry produced in a plasticulture system. 2a and 2b. Field research studies were conducted to determine crop safety and efficacy of herbicides in several vegetable and small fruit crops. 3a. No carryover studies were conducted.4a and 4b. Research results from spectral research is being analyzed and peer-reviewed journal articles are in development.

Publications

  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Mahoney DJ, Jordan DL, Roma-Burgos N, Jennings KM, Leon RG, Vann MC, Everman WJ, Cahoon CW (2020) Susceptibility of Palmer amaranth (Amaranthus palmeri) to herbicides in accessions collected from the North Carolina Coastal Plain. Weed Sci 68(6):582-593
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Lindley JL, Jennings KM, Monks DW, Schultheis JR, Waldschimdt W, Chaudhari S, Brownie C (2020) Effect of bicyclopyrone herbicide on sweetpotato and Palmer amaranth. Weed Technol. 34(4) 552-559. doi.org/10.1017/wet.2020.13
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Meyers SL, Jennings KM, Miller DK, Shankle MW (2020) Response of sweetpotato to diquat applied pre-transplanting. Weed Technol 34(5):637-641. doi:10.1017/wet.2020.27
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Smith SC, Jennings, Monks DW, Schultheis JR, Reberg-Horton C, Chaudhari S (2020) Critical timing of Palmer amaranth (Amaranthus palmeri) removal in sweetpotato. Weed Technol 34(4):547-551. doi:10.1017/wet.2020.1
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Chaudhari S, Jennings KM, Monks DW (2020) Interaction of common purslane and Palmer amaranth with sweetpotato genotypes. Canadian Journal of Plant Science https://doi.org/10.1139/CJPS-2020-0138
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Moore LD, Jennings KM, Monks DW, Boyette MD, Jordan DL, Leon RG (2020) Herbicide systems including linuron for Palmer amaranth (Amaranthus palmeri) control in sweetpotato. Weed Technol. doi:10.1017/wet.2020.63
  • Type: Journal Articles Status: Submitted Year Published: 2020 Citation: Jennings KM, Chaudhari S, Spivey B, Fisher L (2019) Flumetralin carryover to sweetpotato. Tobacco Science.
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Batts TM, Miller DK, Griffin JL, Villordon AO, Stephenson DO, Jennings KM, Chaudhari S, Blouin DC, Copes JT, Smith TP (2020) Impact of reduced rates of 2,4-D and glyphosate on sweetpotato (Ipomoea batatas (L.) Lam) growth and yield. Weed Technol 34(5):631-636. doi:10.1017/wet.2020.57
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Basinger NT, Jennings KM, Hestir EL, Monks DW, Jordan DL, Everman WJ (2020) Phenology affects differentiation of crop and weed species using hyperspectral remote sensing. Weed Technol doi:10.1017/wet.2020.92
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Reinhardt Piskackova TA, Reberg-Horton C, Richardson RJ, Jennings KM, Leon RG (2020) Incorporating environmental factors to describe wild radish (Raphanus raphanistrum L.) seedling emergence and phenology Weed Science 68(6):627-638. Doi:10.1017/wsc.2020.64
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Reinhardt Piskackova TA, Reberg-Horton C, Richardson RJ, Jennings KM, Leon RG (2020) Integrating emergence and phenology models to determine windows of action for weed control: a case study using Senna obsusifolia. Field Crops Research doi.org/10.1016/j.fcr.2020.107959
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Caputo GA, Wadl PA, McCarty L, Adelberg J, Jennings KM, Cutulle M (2020) In vitro safening of bentazon by melatonin in sweetpotato (Ipomoea batatas). HortScience 55(9) 1406-1410. Doi.org/10.21273/HORTSCI15128-20
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Reinhardt Piskackova TA, Reberg-Horton C, Richardson RJ, Jennings KM, Leon RG (2020) Creating predictive weed emergence models using repeat photography and image analysis. Plants (Basel). doi:10.3390/plants9050635
  • Type: Journal Articles Status: Published Year Published: 2020 Citation: Meyers SL, Jennings KM, Chaudhari S, Miller DK, Shankle MS (2020) Response of sweetpotato to pendimethalin application rate and timing. Weed Technol. 34(2), 301-304. doi:10.1017/wet.2019.103
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Mitchem WE, Sims KC, Holmberg C, Jennings KM (2020) Grape (Vitis vinifera) respone to 2,4-D chline applied as a directed spray in vineyards. Weed Sci Soc America
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Moore LD, Jennings KM, Monks DW, Boyette MD, Jordan DL, Leon RG (2020) Using linuron to improve sweetpotato production. Weed Sci Soc America
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Smith SC, Jennings KM, Monks DW, Schwarz MR, Jordan DL, Reberg-Horton C (2020) Sweetpotato tolerance to indaziflam. Weed Sci Soc America
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Sims KC, Jennings K, Monks D (2020) Tolerance of blueberry, strawberry, and muscadine grape to 2,4-D choline. South Weed Sci Soc
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Smith SC, Jennings KM, Monks DW, Schwarz M, Jordan DL, Reberg-Horton SC (2020) Evaluation of a reduced-tillage production system in sweetpotato. National Sweetpotato Collaborators Group
  • Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Moore LD, Jennings KM, Monks DW, Boyette MD, Jordan DL, Leon RG (2020) Evaluation of high density polyethylene row coverings to simulate Palmer amaranth (Amaranthus palmeri) competition in sweetpotato. National Sweetpotato Collaborators Group


Progress 10/01/18 to 09/30/19

Outputs
Target Audience:Vegetable and small fruit growers, commodity groups, extension agents, agrochemical company personnel, faculty at other institutions, and other people in the agricultural community. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Graduate students (MS and PhD) were trained in weed science research methodologies including weed biology and weed control strategies. Graduate students were given the opportunity to present research results at professional meetings, extension meetings, field days, and regional meetings. Presentation and hands on activity was given to extension agents at a field location. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Sweetpotato is an economically important commodity for the southeastern U.S. and California with an approximate farm gate value of $588 million. In 2019 59,717 ha of sweetpotato was produced in the US, with 66% concentrated in the coastal plain of NC (USDA-NASS 2019). Sweetpotato is a highly erodible crop with an estimated soil loss of 49 tonnes ha-1. Severe erosion is caused by the reliance on tillage for weed control and to facilitate production. Prior to planting, the soil is disked and raised beds are formed using a tractor mounted ripper bedder, three cultivations on average are conducted during the growing season to control weeds, and the soil is turned over during harvest. Continuous tillage is a requirement in current production systems but is detrimental to soil structure and decreases soil organic matter content. In other crops such as cotton, corn, and soybean, cover crops are used to reduce reliance on cultivation while increasing soil health. Planting into a rye cover crop mulch can increase soil organic matter content, decrease compaction, and reduce nutrient runoff by increasing water infiltration and soil water storage, and storage of residual NO3-N in residue. The utilization of a high-residue rye cover crop mulch in sweetpotato production has the potential to reduce the need for and impact of tillage. Along with altered productions system, cultivars with varying architectures have potential to reduce in-season cultivation for weed control. Little is known about the impact of a high-residue rye cover crop mulch system on otherwise conventionally managed sweetpotato. Therefore, studies were conducted to determine the effect of productions systems that include high-residue rye cover crop and no rye cover crop on soil health, and growth and storage root yield of sweetpotato cultivars having different vining (upright or sprawling) characteristics. Sweetpotato grown in the conventional system performed better overall than those grown in the reduced-tillage system. Sweetpotato plants had greater canopy growth and produced more storage roots in the conventional system. The differences observed in canopy growth have significant implications for weed management. Large crop canopies are better able to compete for light than small canopies. Large canopies can also serve to out compete later emerging weeds. This suggests that conventional tillage systems result in a more competitive crop than reduced-tillage systems. Due to the reduced rate of canopy width expansion of upright cultivars, relative to sprawling cultivars, cultivation to control weeds can occur later in the season if grown in a conventional system.Refinement of reduced-tillage sweetpotato production systems is needed before grower adoption. Combining Linuron herbicide with Dual Magnum herbicide (S-metolachlor) is too phytotoxic for use in sweetpotato. Linuron applied at either rate provided excellent (≥ 98%) control of Palmer amaranth 1 week after treatment; however, the residual Palmer amaranth control was poor 8 weeks after treatment. The typical recommendation for Dual Magnum application is a window between 7 and 14 days after transplanting sweetpotato in order to increase sweetpotato tolerance while minimizing the risk that weeds emerge prior to application.Dual Magnum is safe when applied 2 weeks after planting in sweetpotato. Therefore, a system including linuron applied 1 week after planting followed by Dual Magnum applied 2 weeks after planting could supplement preemergence weed control such that weeds are better controlled during the critical period of weed control while minimizing the risk that weeds will be present at the Dual Magnum application. This system included with Valor (flumioxazin) or Reflex (fomesafen) applied preplant could greatly reduce the likelihood of PPO (Valor and Reflex are PPO herbicides)-resistant Palmer amaranth surviving while maintaining low yield costs associated with herbicide injury and reducing the amount of hand-removal required. Though linuron has postemergene efficacy, this herbicide will likely not replace a form of late season weed removal in sweetpotato required to reduce the amount of weed seeds added into the soil seedbank, as is commonly practiced by sweetpotato growers in North Carolina. 1a. Field research studies were conducted to determine the effect of Palmer amaranth on sweetpotato growth, yield, and quality. 2a and 2b. Field research studies wereconducted to determine crop safety and efficacy of herbicides in several vegetable and small fruit crops. 3a. Field research studies were conducted to determine the carryover potential of Quelex to sweetpotato. 4a and 4b.Research results from spectral research was analyzed and peer-reviewed journal articles were developed.

Publications

  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Beam SC, Chaudhari S, Jennings KM, Monks DW, Meyers SL, Schultheis JR, Waldschmidt M, Main JL (2019) Response of Palmer amaranth and sweetpotato to flumioxazin/pyroxasulfone. Weed Technol 33(1):128-1334 doi: 10.1017/wet.2018.80
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Chaudhari S, Jennings KM, Culpepper AS, Batts RB (2019) Turnip tolerance to preplant incorporated trifluralin. Weed Technol 33(1): 123-127 doi: 10.1017/ wet.2018.66
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Buckelew JK, Mitchem WE, Monks DW, Chaudhari S, Jennings KM, Mehra LK (2019) Effects of vegetation-free strip width and irrigation on newly planted peach. Internat J of Fruit Sci 19:75-90 doi:10.1080/15538362.2018.1545622
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Basinger NT, Jennings KM, Monks DW, Jordan DL, Everman WJ, Hestir EL, Bertucci MB, Brownie C (2019) Large crabgrass (Digitaria sanguinalis) and Palmer amaranth (Amaranthus palmeri) interspecific and intraspecific interference in sweetpotato. Weed Technol doi:10.1017/wsc.2019.16
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Aldridge RB, Jennings KM, Monks DW, Everman WJ, Chaudhari S (2019) Tolerance of southern highbush and rabbiteye blueberry cultivars to saflufenacil. Weed Technol 33:475-480
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Basinger NT, Jennings KM, Monks DW, Mitchem WE (2019) Effect of rate and timing of indaziflam on Sunbelt and muscadine grape. Weed Technol. 33(2):380-385
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Bertucci MB, Jennings KM, Monks DW, Schultheis JR, Jordan DL, Louws FJ (2019) Critical period for weed control in grafted and nongrafted watermelon grown in plasticulture. Weed Sci 67:221-228 doi: 10.1017/wsc.2018.76
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Bertucci MB, Jennings KM, Monks DW, Schultheis JR, Louws FJ, Jordan DL (2019) Interference of Palmer amaranth (Amaranthus palmeri) density in grafted and nongrafted watermelon. Weed Sci 67(2):229-238 doi: 10.1017/wsc.2018.77
  • Type: Journal Articles Status: Published Year Published: 2019 Citation: Basinger NT, Jennings KM, Monks DW, Jordan DL, Everman WJ, Hestir EL, Bertucci MB, Brownie C (2019) Digitaria sanguinalis and Amaranthus palmeri intraspecific and interspecific interference in soybean. Weed Sci 64(6)649-656
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Smith SC, Jennings KM, Monks DW, Schwarz MR (2019) Response of sweetpotato and yield components to indaziflam. HortScience
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Meyers SL, Jennings KM, Smith TP, Arnold TF, Main JL, Morris C, Waldschimdt MD, Smith SC, Moore LD, Sims KC (2019) Simulated reduced sweetpotato plant stand-an attempt to estimate yield loss and guide replant decisions HortScience
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Moore L, Jennings KM, Monks D, Smith SC, Waldschimdt MD, Sims KC (2019) Efficacy of tank mixes containing linuron for Palmer amaranth control in sweetpotato. HortScience
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Basinger N, Jennings KM, Monks DW, Everman W, Jordan D, Hestir EL (2019) Interference of Amaranthus palmeri S. Wats. and Digitaria sanguinalis (L.) Scop. In soybean. Weed Sci Soc of Amer
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Moore L, Jennings KM, Monks D, Smith SC, Waldschimdt MD, Sims KC (2019) Efficacy of tank mixes containing linuron for Palmer amaranth control in sweetpotato. South Weed Sci Soc
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Reinhardt Piskackova TA, Jennings KM, Richardson R, Reberg-Horton C, Leon R (2019) Describing phenology patterns of different natural cohorts of sicklepod (Senna obtusifolia (L) Irwin & Barneby) using sigmoidal models. Weed Sci Soc of Amer
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Smith SC, Jennings KM, Chaudhari S, Monks D (2019) Response of sweeetpotato to fluridone alone or in combination with flumioxazin followed by S-metolachlor. Weed Sci Soc of Amer
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Mahoney DJ, Jordan D, Hare AT, Burgos NR, Jennings KM, Leon R, Vann MC (2019) Palmer amaranth growth and fecundity in competition with various row crops in North Carolina. Weed Sci Soc of Amer
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Chaudhari S, Jennings KM, Monks D, Smith SC, Moore LD (2019) Response of sweetpotato to fluridone preplant followed by irrigation. Weed Sci Soc of Amer
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Reinhardt Piskackova TA, Jennings KM, Richardson R, Regberg-Horton C, Leon R (2019) Wild radish (Raphanus raphanistrum L.) seedling emergence in NC. South Weed Sci Soc
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Mahoney DJ, Jordan D, Hare AT, Burgos NR, Jennings KM, Leon R, Vann MC (2019) State of resistance for Palmer amaranth populations from the North Carolina Coastal Plain. South Weed Sci Soc
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Basinger N, Jennings KM, Monks D, Jordan D, Everman W, Hestir EL, Waldschimdt MD, Smith SC, Brownie C (2019) Interspecific and intraspecific interference of Palmer amaranth (Amaranthus palmeri) and large crabgrass (Digitaria sanguinalis) in sweetpotato. South Weed Sci Soc
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Smith SC, Jennings KM, Monks D, Schwarz M, Moore L, Waldschimdt MD (2019) Sweetpotato tolerance to indaziflam. South Weed Sci Soc
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Moore L, Jennings KM, Monks D, Smith SC, Waldschimdt MD, Sims KC (2019) Efficacy of tank mixes containing linuron for Palmer amaranth control in sweetpotato. South Weed Sci Soc
  • Type: Conference Papers and Presentations Status: Published Year Published: 2019 Citation: Chaudhari S, Jennings KM, Shankle M, Smith SC, Waldschimdt MD, Moore L, Sims K (2019) Sweetpotato response to selected herbicides. South Weed Sci Soc
  • Type: Book Chapters Status: Published Year Published: 2019 Citation: Monks DW, Jennings KM, Meyers SL, Smith TP, and Korres N (2019) Weed Control, Sustainability, Hazards and Risks in Sweetpotato Cropping Systems. In Korres N, Burgos NR, Duke SO (eds.), Weed Control: Sustainability, Hazards, and Risks in Cropping Systems Worldwide. 1st Edition. CRC Press/Taylor and Francis Group, Enfield, NH, USA
  • Type: Other Status: Published Year Published: 2019 Citation: Bertucci MB, Burgos N, McWhirt A, Jennings K, Monks D (2019) Weed Control in Arkansas Watermelon Production. University of Arkansas Cooperative Extension Service. FSA2186-PD-5-2019N


Progress 10/01/17 to 09/30/18

Outputs
Target Audience:Vegetable and small fruit growers, commodity groups, extension agents, agrochemical company personnel, faculty at other institutions, and other people in the agricultural community. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Graduate students (MS and PhD) were trained in weed science research methodologies including weed biology and weed control strategies. Graduate students were given the opportunity to present research results at professional meetings, extension meetings, field days, and regional meetings. How have the results been disseminated to communities of interest? Nothing Reported What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Objective 1a. In 2017, an estimated 6,500 acres of watermelon were harvested in NC (approximately $20 million). In a high-value crop like watermelon, a zero-threshold model is frequently adopted for weed control. According to a survey by the Southern Weed Science Society, Palmer amaranth is the most troublesome and common weed in North Carolina watermelon production. Growers face high densities of Palmer amaranth in almost every field in North Carolina, requiring great expense for hand labor, cultivation and herbicides for control. This fast growing (potential of over 2 inches per day) and prolific (over 800,000 seeds per female plant) weed reduces yield and increases loss during the harvest operation. It's important to characterize the competitive relationship of watermelon and Palmer amaranth. Grafting of watermelon has become of great interest to growers as it can be utilized to improve biotic and abiotic stress tolerance of watermelon. Given the reported benefits of watermelon grafting, our objectives was to investigate whether grafting could play a role in mitigating yield loss due to weed interference. No guidelines existed for growers as to when they should implement hand labor for removal of Palmer amaranth, nor was there an effective herbicide program available for controlling this weed. Therefore, field studies and extension programs were conducted on research stations in North Carolina to determine the competitive ability of grafted and nongrafted watermelon when exposed to season-long interference by Palmer amaranth at increasing weed densities and to determine a control program to best manage this weed. From these studies, a threshold model was developed by determining the effect of Palmer amaranth density of 0, 1, 2, 3, and 4 Palmer amaranth per watermelon planting hole (i.e. 0.76 m row). In addition, the effect of intraspecific competition and seed production potential of Palmer amaranth at varying population densities in a watermelon field was determined. The impact of this work (new models for managing weeds in watermelon, watermelon tolerance to herbicides) will greatly aid growers in making decisions in weed management in watermelon and farm profitability, and will lead to new herbicide registrations in this crop. Relatively low populations of Palmer amaranth can cause substantial yield losses in watermelon production. Watermelon yield and fruit number differed depending on rootstock chosen. When Kazako rootstock was used relative yield loss and fruit number reductions were higher than when Carnivor rootstock or nongrafted Exclamation was used. Nongrafted Exclamation produced the highest yield and fruit number, regardless of weed interference. Thus, there is no apparent benefit in competitive ability associated with grafted watermelon. Grafted seedlings may cost $0.75 per seedling compared to $0.28 per nongrafted triploid watermelon seedling; thus, grafting is not an economically viable option for weed management. While grafting may offer disease resistance and tolerance to abiotic stresses, there is no immediate benefit regarding weed-competitive ability and there appears to be a consistent yield penalty associated with grafting, even in weed-free treatments. However, if grafting is economically justified based on disease in a field, the Carnivor rootstock is a higher yielding and more weed-competitive alternative to Kazako rootstock. The results of this research inform watermelon growers when weeds must be controlled during the growing season and whether grafted watermelon must be managed differently from non-grafted watermelon. There have been few studies in these areas of weed science in watermelon. Objective 1a. In 2017, an estimated 90,000 acres of marketable sweetpotato roots were harvested in NC (approximately $350 million) and marketed nationally 65%) and internationally (35%). North Carolina is the largest sweetpotato producing state, accounting for 54% of US production (USDA-NASS 2017). Unfortunately, due to its prostrate growth habit and relatively slow growth, sweetpotato does not compete well with problematic weeds, resulting in reduced yields. According to a survey by the Southern Weed Science Society, large crabgrass is in the top five most common weeds in North Carolina sweetpotato. Large crabgrass is commonly found in fruit and vegetable crops but has not been highly ranked as a problematic weed due to efficacious postemergence herbicides such as clethodim, fluazifop, or sethoxydim. Although these graminicides can be effective, annual grasses escaping herbicide application, or sprayed after substantial establishment may continue to compete with the crop and reduce yields. In recent years, timing of graminicide herbicide application in sweetpotato is not optimal. In other vegetable crops, the effect of season-long large crabgrass competition has been documented. Season-long large crabgrass reduced yield in bell pepper by 46%, snap bean by 47 to 50% and watermelon by 82%. A better understanding of the interaction of large crabgrass with sweetpotato would allow for better decision making and implementation of control by growers. Field studies were conducted on research stations in North Carolina to determine the effect of five densities of large crabgrass on sweetpotato biomass, and storage root yield and quality, (2) determine the intraspecific response of large crabgrass across five densities with and without sweetpotato, and (3) determine the effect of sweetpotato on growth of large crabgrass. From these studies, a threshold model was developed by determining the effect of large crabgrass density (0, 1, 2, 4, and 16 large crabgrass plants per m of row) on marketable yield. Growers use this model in decision-making when considering a graminicide application for postemergence large crabgrass control in sweetpotato Prior to this research, growers did not believe that large crabgrass had great effect on sweetpotato growth and yield. The models developed and adopted by growers will save growerers nationally and locally millions of dollars. Objective 2a and 2b. Several research studies were conducted to determine crop safety and optimum weed control with several herbicides in various vegetable and fruit crops. Data was collected and analyzed and reports and/or journal articles and/or extension publications were written. Objective 3. Field study was conducted, data collected, and report was written. Objectives 4a and 4b. Research studies were conducted, data collected, and preliminary analysis was conducted.

Publications

  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Basinger N, Jennings KM, Hestir EL, Monks D, Jordan D, Everman W (2018) Species differentiation and spectral variability of crop and weed species using hyperspectral remote sensing. South Weed Sci Soc 71
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Smith SC, Jennings KM, Monks DW, Schultheis JR, Reberg-Horton C (2018) Tolerance of sweetpotato to herbicides applied in plant propagation beds. Weed Technol 33(1):147-152
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: McGowen SJ, Jennings KM, Monks DW, Schultheis JR, Reberg-Horton C, Chaudhari S (2018) Critical period for Palmer amaranth (Amaranthus palmeri) control in pickling cucumber. Weed Technol 32(5) 586-591
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Bertucci MB, Suchoff D, Jennings KM, Monks DW, Schultheis JR, Jordan DL, Louws FJ (2018) Comparison of root system morphology of cucurbit rootstocks for use in watermelon grafting. HortTechnology 28(5):625-636
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Beam SC, Jennings KM, Chaudhari S, Monks DW, Schultheis JR and Waldschmidt M (2018) Response of sweetpotato cultivars to linuron rate and application time. Weed Technol doi: 10.1017/wet.(2018)68
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Chaudhari S, Jennings KM, Meyers SL (2018) Response of sweetpotato (Ipomoea batatas) to oryzalin application rate and timing. Weed Technol 32(6):722-725 doi: 10.1017/ Q23 wet.2018.79
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Bertucci MB, Jennings KM, Monks DW, Schultheis JR, Perkins-Veazie P, Louws FJ, Jordan DL (2018) Early season growth, yield, and fruit quality of standard and mini watermelon grafted onto several commercially available cucurbit rootstocks. HortTechnol 28(4):459-469
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Bertucci MB, Jennings KM, Monks DW, Schultheis JR, Jordan DL, Louws FJ (2018) Effect of bicyclopyrone on triploid watermelon in plasticulture. Weed Technol 32(4):439-443
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Dittmar PJ, Schultheis JR, Jennings KM, Monks DW, Chaudhari S, Meyers S, Jiang C (2018) Effect of cultivar, ethephon, flooding, and storage duration on sweetpotato internal necrosis. HortTechnol 28:246-251
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Basinger NT, Jennings KM, Monks DW, Mitchem WE, Chaudhari S, Heitman JL, Havlin JL, Howard AM, Spayd SE (2018) Vegetation-free strip width affects growth, berry composition, and yield of Cabernet Franc in vigorous growing environments. Catalyst doi:10.5344/catalyst.(2018)17005
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Buckelew JK, Mitchem WE, Chaudhari S, Monks DW, Jennings KM (2018) Evaluating weed control and response of newly planted peach trees to herbicides. Internat J of Fruit Sci 1-11. doi: .org/10.1080/15538362.(2018)1441772
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Basinger NT, Jennings KM, Monks DW, Mitchem WE, Perkins-Veazie PM (2018) In-row vegetation-free strip width effect on established Navaho blackberry. Weed Technol 32(1):85-89
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Basinger N, Jennings K, Hestir EL, Monks D, Jordan D (2018) Remote determination of weed species and density in sweetpotato (Ipomoea batatas) using in-situ spectroscopy. Weed Sci Soc of Amer 58:139
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Smith SC, Jennings KM, Monks DW (2018) Tolerance of sweetpotato to herbicides applied in plant propagation beds. Weed Sci Soc of Amer 58:135
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Chaudhari S, Jennings KM, Meyers SL, Miller D (2018) Application timing and rate effects of oryzalin on sweetpotato tolerance. Weed Sci Soc of Amer 58:60
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Bertucci MB, Jennings KM, Monks DW, Jackson B, Bartley P (2018) Automated seed counts and verification of seed production estimates of Palmer amaranth using a computerized particle analyzer. Weed Sci Soc of Amer 58:12
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Smith SC, Jennings KM, Monks DW (2018) Tolerance of sweetpotato to herbicides applied in plant propagation beds. South Weed Sci Soc 71
  • Type: Conference Papers and Presentations Status: Published Year Published: 2018 Citation: Bertucci MB, Jennings KM, Monks DW, Jackson B, Bartley P (2018) Automated seed counts and verification of seed production estimates of Palmer amaranth using a computerized particle analyzer. South Weed Sci Soc 71
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Bertucci MB, Jennings KM, Monks DW, Jordan DL, Schultheis JR, Lowes FJ (2018) Palmer amaranth interference and seed production in grafted and nongrafted watermelon. South Weed Sci Soc 71


Progress 10/01/16 to 09/30/17

Outputs
Target Audience:Vegetable and small fruit growers, commodity groups, extension agents, agrochemical company personnel, faculty at other instituitions, and other people in the agricultural community. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?Graduate students (MS and PhD) were trained in weed science research including weed biology and weed control strategies. How have the results been disseminated to communities of interest?Results have been presented at the Southeast Vegetable and Fruit Expo, the NC Sweetpotato Commission field day and meetings, the NC Blueberry Council meeting, the Southern Weed Science Society, the Weed Science Society of North Carolina, Weed Science Society of America, and the Southeast Regional Fruit and Vegetable Conference. Journal articles have been published. Extension publications have been published. What do you plan to do during the next reporting period to accomplish the goals?Continue to conduct research to determine tolerance of vegetable and small fruit crops to herbicides and crop/weed interference. Continue providing information at local, regional, and national meetings. Continue publishing results in scientific journals and extension publications.

Impacts
What was accomplished under these goals? Impact 1. In 2017, an estimated 6,500 acres of watermelon were harvested in NC (approximately $20 million). In a high-value crop like watermelon, a zero-threshold model is frequently adopted for weed control. According to a survey by the Southern Weed Science Society, Palmer amaranth is the most troublesome and common weed in North Carolina watermelon production. Growers face high densities of Palmer amaranth in almost every field in North Carolina, requiring great expense for hand labor, cultivation and herbicides for control. This fast growing (potential of over 2 inches per day) and prolific (over 800,000 seeds per female plant) weed reduces yield and increases loss during the harvest operation. It's important to characterize the competitive relationship of watermelon and Palmer amaranth. Grafting of watermelon has become of great interest to growers as it can be utilized to improve biotic and abiotic stress tolerance of watermelon. Given the reported benefits of watermelon grafting, our objectives was to investigate whether grafting could play a role in mitigating yield loss due to weed interference. No guidelines existed for growers as to when they should implement hand labor for removal of Palmer amaranth, nor was there an effective herbicide program available for controlling this weed. What has been done to address the issue?Field studies and extension programs were conducted on research stations in North Carolina to determine the competitive ability of grafted and nongrafted watermelon when exposed to season-long interference by Palmer amaranth at increasing weed densities and to determine a control program to best manage this weed. From these studies, a threshold model was developed by determining the effect of Palmer amaranth density of 0, 1, 2, 3, and 4 Palmer amaranth per watermelon planting hole (i.e. 0.76 m row). In addition, the effect of intraspecific competition and seed production potential of Palmer amaranth at varying population densities in a watermelon field was determined. What was the impact of addressing the issue?The impact of this work (new models for managing weeds in watermelon, watermelon tolerance to herbicides) will greatly aid growers in making decisions in weed management in watermelon and farm profitability, and will lead to new herbicide registrations in this crop. Relatively low populations of Palmer amaranth can cause substantial yield losses in watermelon production. Watermelon yield and fruit number differed depending on rootstock chosen. When Kazako rootstock was used relative yield loss and fruit number reductions were higher than when Carnivor rootstock or nongrafted Exclamation was used. Nongrafted Exclamation produced the highest yield and fruit number, regardless of weed interference. Thus, there is no apparent benefit in competitive ability associated with grafted watermelon. Grafted seedlings may cost $0.75 per seedling compared to $0.28 per nongrafted triploid watermelon seedling; thus, grafting is not an economically viable option for weed management. While grafting may offer disease resistance and tolerance to abiotic stresses, there is no immediate benefit regarding weed-competitive ability and there appears to be a consistent yield penalty associated with grafting, even in weed-free treatments. However, if grafting is economically justified based on disease in a field, the Carnivor rootstock is a higher yielding and more weed-competitive alternative to Kazako rootstock. The results of this research inform watermelon growers when weeds must be controlled during the growing season and whether grafted watermelon must be managed differently from non-grafted watermelon. There have been few studies in these areas of weed science in watermelon. This research was part of a PhD research project conducted by Matt Bertucci. From the results of his research studies Matt published 5 out of 6 peer-reviewed journal articles and wrote an extension publication (in review) entitled "Weed Control in North Carolina Watermelon". Matt also presented his research results at several scientific conferences and he won numerous awards related to his research including the following: Krezdorn Excellence in Doctoral Research Award2019,First Place PhD Paper: SWSS Annual Meeting2018,SWSS Endowment Enrichment Scholarship2017,Second Place Poster: WSSNC Annual Meeting2017,First Place PhD Paper: WSSA Annual Meeting2017,Second Place WSSA Photo Contest 2017,Second Place PhD Paper: SR-ASHS Annual Meeting2017,Second Place PhD Paper: SWSS Annual Meeting2017, WSSA Graduate Student Travel Award 2017. This research was funded, in part, by USDA-NIFA-2011-51181-30963. Impact 2. In 2017, an estimated 90,000 acres of marketable sweetpotato roots were harvested in NC (approximately $350 million) and marketed nationally 65%) and internationally (35%). North Carolina is the largest sweetpotato producing state, accounting for 54% of US production (USDA-NASS 2017). Unfortunately, due to its prostrate growth habit and relatively slow growth, sweetpotato does not compete well with problematic weeds, resulting in reduced yields. According to a survey by the Southern Weed Science Society, large crabgrass is in the top five most common weeds in North Carolina sweetpotato. Large crabgrass is commonly found in fruit and vegetable crops but has not been highly ranked as a problematic weed due to efficacious POST herbicides such as clethodim, fluazifop, or sethoxydim. Although these graminicides can be effective, annual grasses escaping herbicide application, or sprayed after substantial establishment may continue to compete with the crop and reduce yields. In recent years, timing of graminicide herbicide application in sweetpotato is not optimal. In other vegetable crops, the effect of season-long large crabgrass competition has been documented. Season-long large crabgrass reduced yield in bell pepper by 46%, snap bean by 47 to 50% and watermelon by 82%. A better understanding of the interaction of large crabgrass with sweetpotato would allow for better decision making and implementation of control by growers. What has been done to address the issue?Field studies were conducted on research stations in North Carolina to determine the effect of five densities of large crabgrass on sweetpotato biomass, and storage root yield and quality, (2) determine the intraspecific response of large crabgrass across five densities with and without sweetpotato, and (3) determine the effect of sweetpotato on growth of large crabgrass. From these studies, a threshold model was developed by determining the effect of large crabgrass density (0, 1, 2, 4, and 16 large crabgrass plants per m of row) on marketable yield. What was the impact of addressing the issue?Growers use this model in decision-making when considering a graminicide application for postemergence large crabgrass control in sweetpotato Prior to this research, growers did not believe that large crabgrass had great effect on sweetpotato growth and yield. The models developed and adopted by growers will save growerers nationally and locally millions of dollars. This research was funded, in part, by the NC SweetPotato Commission.

Publications

  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Chaudhari S, DL Jordan, AC York, KM Jennings, CW Cahoon, A Chandi, MD Inman. 2017. Biology and management of glyphosate-resistant and glyphosate-susceptible Palmer amaranth (Amaranthus Palmeri) phenotypes from a segregating population. Weed Sci. 65:755-768.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Besancon TE, KM Jennings, W Everman. 2017. Absorption, translocation, and metabolism of halosulfuron in cucumber, summer squash, and selected weeds. Weed Sci. 65(4):461-467.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Beam, SC, KM Jennings, DW Monks, JR Schultheis, S Chaudhari. 2017. Influence of herbicides on the development of internal necrosis of sweetpotato. Weed Technol. 31(6):863-869.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Meyers SL, KM Jennings, DW Monks. 2017. Sweetpotato tolerance and Palmer Amaranth control with metribuzin and oryzalin. Weed Technol. 31(6):903-907.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Chaudhari S, KM Jennings, DW Monks, DL Jordan, CC Gunter, FJ Louws. 2017. Absorption, translocation, and metabolism of 14C-Halosulfuron in grafted eggplant and tomato. Weed Sci. 31(6):908-914.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Dayton DM, Chaudhari S, KM Jennings, DW Monks, GD Hoyt. Effect of drip-applied metam sodium and S-metolachlor on yellow nutsedge and common purslane in polyethylene-mulched bell pepper and tomato. 2017. Weed Technol. 31(3):421-429.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Coneybeer-Roberts MM, KM Jennings, D.W. Monks, M.G. Burton, P.S. Stowe. 2017. Seed biology of the weed Maryland Meadowbeauty (Rhexia mariana L.) in blueberry (Vaccinium spp.). Internat. J. Fruit Sci. 17(3):323-332. DOI dx.doi.org/10.1080/15538362.2017.1317316.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Meyers SL, KM Jennings, DW Monks. 2017. Sweetpotato response to simulated glyphosate wick drip. Weed Technol. 31(1):130-135.
  • Type: Journal Articles Status: Published Year Published: 2017 Citation: Barkley, SL, JR Schultheis, S Chaudhari, SD Johanningsmeier, KM Jennings, VD Truong, DW Monks. 2017. Yield and consumer acceptability of Evangeline sweetpotato for production in North Carolina. HortTechnol. 27(2):281-290.
  • Type: Journal Articles Status: Accepted Year Published: 2017 Citation: Basinger NT, KM Jennings, DW Monks, WE Mitchem, S Chaudhari, JL Heitman, JL Havlin, AM Howard, SE Spayd. 2018. Vegetation-free strip width affects growth, berry composition, and yield of Cabernet Franc in vigorous growing environments. Catalyst
  • Type: Book Chapters Status: Published Year Published: 2017 Citation: Jennings KM 2017. Dodder. In A. Keinath (eds.), Compendium of Diseases, Pests, and Disorders for Cucurbits. 2nd Edition. APS Press, St. Paul, MN, USA.
  • Type: Book Chapters Status: Published Year Published: 2017 Citation: Jennings KM 2017. Herbicide injury. In A. Keinath (eds.), Compendium of Diseases, Pests, and Disorders for Cucurbits. 2nd Edition. APS Press, St. Paul, MN, USA.
  • Type: Book Chapters Status: Published Year Published: 2017 Citation: Jennings KM 2017. Herbicide injury. In K.V. Subbarao (eds.), Compendium of Diseases, Pests, and Disorders for Lettuce. 2nd Edition. APS Press, St. Paul, MN, USA.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Smith SC, KM Jennings, DW Monks. 2017. Timing of Palmer amaranth removal on sweetpotato yield and quality. Southern Weed Science Society Proceedings 70:72.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Basinger NT, KM Jennings, DW Monks, WE Mitchem. 2017. Effect of in-row vegetation-free strip width on growth, yield, and fruit quality of 'Navaho' blackberry. Southern Weed Science Society Proceedings 70:131.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Bertucci MB, DW Monks, KM Jennings, DL Jordan, FJ Louws, JR Schultheis. 2017. Critical period for weed control in grafted vs nongrafted watermelon. Southern Weed Science Society Proceedings 70:229.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Bertucci MB, KM Jennings, Monks, DW, JR Schultheis, WB Thompson, FM Louws, DL Jordan, NA Basinger, SC Smith, MD Waldschimdt. 2017. Early season crop development, yield, and fruit quality of standard and mini watermelons grafted to several Cucurbit rootstocks
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Chaudhari S, KM Jennings, DW Monks. 2017. Interaction of common purslane and Palmer amaranth with two sweetpotato cultivars. Weed Science Society of America Proceedings. 57:69.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Beam SC, KM Jennings, DW Monks, MD Waldschimdt, NT Basinger, MB Bertucci, SJ McGowen. 2017. Weed Science Society of America Proceedings. 57:191.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Basinger NT, KM Jennings, DW Monks, EL Hestir, WJ Everman, DL Jordan. 2017. Hyperspectral reflectance spectroscopy for multiple crop and weed species differentiation. Weed Science Society of America Proceedings. 57:190.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Bertucci MB, KM Jennings, DW Monks, DL Jordan, FJ Louws, JR Schultheis. 2017. Influence of grafting on the critical period for weed control in watermelon. Weed Science Society of America Proceedings. 57:198.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Smith SC, KM Jennings, DW Monks. 2017. Impact of Palmer amaranth (Amaranthus palmeri) removal on sweetpotato yield and quality. National Sweetpotato Collaborators Meeting.
  • Type: Conference Papers and Presentations Status: Published Year Published: 2017 Citation: Jennings KM. Efficacy and crop safety of bicyclopyrone herbicide in sweetpotato. 2017. Southern Region American Society for Horticultural Science.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Basinger NA, KM Jennings, DW Monks, EL Hestir, WJ Everman, DL Jordan. 2017. Utilizing hyperspectral reflectance for differentiation of multiple crop and weed species. Weed Science Society of North Carolina.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Smith, SC, KM Jennings, and DW Monks. 2017. Timing of Palmer amaranth removal on sweetpotato yield and quality. Weed Science Society of North Carolina.
  • Type: Conference Papers and Presentations Status: Other Year Published: 2017 Citation: Bertucci MB, KM Jennings, Monks, DW, JR Schultheis, WB Thompson, FJ Louws, DL Jordan, NA Basinger, SC Smith, MD Waldschimdt. 2017. Influence of grafting on the critical period for weed control in watermelon. Weed Science Society of North Carolina.
  • Type: Books Status: Published Year Published: 2018 Citation: Monks DW, KM Jennings, SL Meyers, TP Smith, N Korres Weed Control: Sustainability, Hazards, and Risks in Cropping Systems Worldwide Weed Control, Sustainability, Hazards and Risks in Sweetpotato Cropping Systems Publisher: CRC Press/Taylor and Francis Group Editor: N Korres, NR Burgos, SO Duke
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Beam SC, KM Jennings, S Chaudhari, DW Monks, SL Meyers, JR Schultheis, and J Main Weed Technology Palmer amaranth control and tolerance of sweetpotato (Ipomoea batatas) to flumioxazin/pyroxasulfone DOI: doi:10.1017/wet.2018.80 Publisher: Cambridge University Press Editor: Jason Norsworthy
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Buckelew J, WE Mitchem, DW Monks, S Chaudhari, KM Jennings, LK Mehra Publication Date: November 2018 International Journal of Fruit Science Effects of vegetation-free strip width and irrigation on newly planted peach Volume & Issue: 19(1) Page Number(s): 75-90 DOI: https://doi.org/10.1080/15538362.2018.1545622 Publisher: Taylor & Francis
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Chaudhari S, KM Jennings, SL Meyers Weed Technology Response of sweetpotato (Ipomoea batatas) to oryzalin application rate and timing Volume & Issue: 32 Page Number(s): 722-725 DOI: 10.1017/wet.2018.79 Publisher: Cambridge University Press Editor: Jason Norsworthy
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Basinger NT, KM Jennings, DW Monks, WE Mitchem, PM Perkins-Veazie, S Chaudhari Publication Date: February 2018 Page Number(s): 85-89 DOI: 10.1017/wet.2017.85 Weed Technology In-row vegetation-free strip width effect on established Navaho blackberry Publisher: Cambridge University Press Editor: Jason Norsworthy
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Buckelew, JK, WE Mitchem, S Chaudhari, DW Monks, and KM Jennings Publication Date: February 21 2018 ISSN: 1553-8362 DOI: 10.1080/15538362.2018.1441772 International Journal of Fruit Science Evaluating weed control and response of newly planted peach trees to herbicides Publisher: Taylor and Francis
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Jordan DL, S Chaudhari, T Grey, E Prostko, and K Jennings Publication Date: February 19, 2018 DOI: doi.org/10.3146/PS17-19.1 Peanut Science Weed control and peanut (Arachis hypogaea L.) response to acetochlor alone and in combination with various herbicides Publisher: American Peanut Research and Education Society
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Bertucci MB, KM Jennings, DW Monks, JR. Schultheis, FJ Louws, DL Jordan, C. Brownie Publication Date: September 3, 2018 Weed Science Critical period for weed control in grafted and nongrafted watermelon grown in plasticulture Publisher: Cambridge University Press Editor: William K. Vencill
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Published Journal Article Bertucci MB, Suchoff DH, Jennings KM, Monks DW, Gunter CC, Schultheis JR, Louws FJ Publication Date: October 2018 HortTechnology Comparison of root system morphology of cucurbit rootstocks for use in watermelon grafting Publisher: ASHS Editor: Neal E. De Vos
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Bertucci MB, KM Jennings, DW Monks, DL Jordan, JR Schultheis, FJ Louws, MD Waldschimdt Publication Date: June 21 2018 Page Number(s): 439-443 DOI: 10.1017/wet.2018.36 Weed Technology Effect of bicyclopyrone on triploid watermelon in plasticulture Publisher: Cambridge University Press Editor: Jason Norsworthy Volume & Issue: 32(4)
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Published Journal Article Beam SC, KM Jennings, S Chaudhari, DW Monks, and JR Schultheis Publication Date: November 2018 Weed Technology Response of sweetpotato (Ipomoea batatas) cultivars to linuron rate and timing alone or with S-metolachlor Volume & Issue: 32(6) Page Number(s): 665-670 DOI: 10.1017/wet2018.68 Publisher: Cambridge University Press Editor: Jason Norsworthy
  • Type: Journal Articles Status: Published Year Published: 2018 Citation: Published Journal Article Bertucci MB, KM Jennings, DW Monks, JR Schultheis, P Perkins-Veazie, FJ Louws, DL Jordan Publication Date: August 2018 Page Number(s): 459-469 DOI: 10.21273/HORTTECH04051-18 HortTechnology Early season growth, yield, and fruit quality of standard and mini watermelon grafted onto several commercially available cucurbit rootstocks Publisher: American Society for Horticultural Science Editor: Neal E. De Vos Volume & Issue: 28(4)