Source: PENNSYLVANIA STATE UNIVERSITY submitted to NRP
DEVELOPMENT OF ACTION THRESHOLDS FOR MANAGING SPOTTED LANTERNFLY IN VINEYARDS
Sponsoring Institution
National Institute of Food and Agriculture
Project Status
ACTIVE
Funding Source
OTHER GRANTS
Reporting Frequency
Annual
Accession No.
1030964
Grant No.
2023-70006-40597
Cumulative Award Amt.
$200,000.00
Proposal No.
2023-02962
Multistate No.
(N/A)
Project Start Date
Sep 1, 2023
Project End Date
Jul 31, 2026
Grant Year
2023
Program Code
[ARDP]- Applied Research and Development Program
Recipient Organization
PENNSYLVANIA STATE UNIVERSITY
408 Old Main
UNIVERSITY PARK,PA 16802-1505
Performing Department
(N/A)
Non Technical Summary
Grapes are the highest value fruit crop in the U.S valued at over $6.5 billion dollars. Vineyards are challenged by a variety of diseases and insect pest, including spotted lanternfly (SLF). SLF feeding is detrimental to grapevines causing yield losses of up to 90%, along with a reduction in wine quality, vine decline and death. These insects were accidentally introduced to Pennsylvania in 2014 and have spread to 13 additional States posing a threat to the U.S. grape and wine industry. Currently, chemical pesticides are the most common strategy for controlling SLF populations. Grape growers have reported an increased use of pesticide sprays in their vineyards that has considerably augmented their production costs and reduced their profit. Grape growers are aware of the importance of controlling SLF in their vineyards, but they are uncertain on when to apply control tactics. The goal of this proposal is to develop action thresholds to help guide growers on the appropriate SLF densities (number of insects per plant) that need to be targeted to avoid economic loss. Economic thresholds are the basis of insect pest management programs, and their use leads to a more efficient use of pesticides, reduction of environmental and human health risks, higher economic benefits to growers, and reduction of pest populations. Field-established grapevines will be enclosed in mesh cages and infested with diferent numbers of SLF individuals (from 0 to ~320). At the end of the growing season, the vines will be harvested and weighed to determine yield. Additionally, several grapes from each vine will be used for winemaking. The relationship between the number of SLF per vine and the resulting yield and wine quality will be assessed with appropriate statistical methods. This information will help determine the number of SLF individuals per vine that causes yield or wine quality loss. These data along with data on SLF management costs obtained from grape growers with previous SLF infestations will be used to calculate action thresholds for this insect. Action thresholds are the basis of insect pest management programs, they help guide growers on the appropriate timing to apply control strategies and often help reduce pesticide applications. This research is critical and timely for the grape and wine industry that deals with the threads of this devastating invasive insect pest.?
Animal Health Component
100%
Research Effort Categories
Basic
(N/A)
Applied
100%
Developmental
(N/A)
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
21611391130100%
Knowledge Area
216 - Integrated Pest Management Systems;

Subject Of Investigation
1139 - Grapes, general/other;

Field Of Science
1130 - Entomology and acarology;
Goals / Objectives
The goal of this proposal is to estimate action thresholds for spotted lanternfly (SLF) management in two economically important V. vinifera cultivars, Cabernet Franc (red grape), and Chardonnay (white grape).Current knowledge indicates that repeated and heavy infestations of SLF reduce yield, wine quality and cause grapevine death. However, the insect density (SLF individuals per vine) able to cause yield losses and plant decline are unknown. Neither is known the number of yearly SLF infestations needed to kill a vine. This information is critical for SLF management because it helps determine the need to apply insect-suppressing techniques at any given time. The estimation of yield loss per insect, along with the estimated cost of insect control, will help determine economic decision levels for SLF.The estimation of economic thresholdsallows for a more rational pesticide use leading to environmental quality conservation and to economic benefits for growers.The specific research objectivesof this project are: 1) to determine the effect of various SLF densities on grapevine yield and wine quality, 2) to determine the number of SFL individuals that should trigger management actions, and 3) to determine the grapevine damage boundary caused by SLF.
Project Methods
Location. The field experiments of this proposal will be carried out at the Penn State Fruit Research and Extension Center (FREC) located in Adams County, PA. For our experiments, we will use 21-year-old vines of theV. viniferacultivar Cabernet Francand Chardonnay.Methods for objective 1Grapevines enclosed in cages of mesh fabric will be exposed to various numbers of SLF individuals early and late in the growing season, as described in the treatments below. The infestation levels will be 0, 1, 2...15 SLF individuals per shoot. Each vine will be an experimental unit and will be randomly assigned to only one level of SLF infestation.Treatments:a) Grapevines exposed to various infestation levels of SLFnymphsearly in the season. These vines will be caged and infested with SLF nymphs 1-4th from early Jun to mid-August only.b)Grapevines exposed to various infestation levels of SLFadultslate in the season. These vines will be caged and infested with SLF adults from mid-August to early November.c) Grapevines exposed to various infestation levels of SLFnymphs and adultsearly and late in the season.These vines will be caged and infested with nymphs (1-4th)in early June. In mid-August, the vines will be infested with adults. These vines will be enclosed in cages from June to November.Cage Effect.To determine the effect of the cage on yield loss and wine quality, vines without SLF will be enclosed in similar mesh cages used for the treatments a-c above. Each of the following controls will have five vines.Grapevines without SLF caged early in the season.These vines will be caged fromearly June- Mid August (control treatment a).Grapevines without SLF caged late in the season.These vines will be caged from mid-August to Novemberat (control treatment b).Grapevines without SLF, caged early and late in the season.These vines will be cagedfromearly June to November (control treatment c)Grapevines without SLF that will not be caged at any time during the growing season.These will be our absolute controls to calculate the effect of the cages on yield loss and wine quality.Effect of various levels of SLF infestation on yield loss.Yield will be quantified by counting the number of clusters and registering the total weight of harvested grapes per vine. The relationship between yield (number of clusters and total weight) and the number of SLF individuals will be calculated with a regression analysis. We will obtain aregression equation:Y = a + bx.Where Y = yield per vine, a = constant (intercept), b = slope (yield loss per number of insects), and x = number of insects per vine.The effect of the cages on yield will be calculated by an Analysis of variance (ANOVA) of the caged treatments and the uncaged controls followed by pairwise comparisons. If a significant effect of the cage is found for any of the treatments, the values of the corresponding treatment (a,borc) will be corrected for that difference before their use for regression analysis.Effect of various levels of SLF infestation on wine quality.Grapes will be picked from each of the treatments and either crushed and fermented within 12 hours or refrigerated with fermentation initiating within 48 hours.We will measure pH, degrees Brix and titratable acidity (TA) in flesh juice. The pH and Brix will be measuredon clarified juice, and the titratable acidity will be measured by titrating the juice with NaOH. Small scale replicated wine lots will be created from each of the treatments at a 50 ml scale using typical nutrient and yeast addition rates and using a minimum of 100 randomly selected berries per ferment. Wines will be fermented to dryness at 30°C with the cap reintegrated twice a day. The finished wines will be used to quantify total anthocyanins, total phenolics and tannins following the Adams Harbertson protocol (Harbertson et al. 2003). The characterization of wine aroma compounds from the small fermentations will be carried out using GC-MS coupled with SPME (solid phase microextraction). Authentic aroma standard for major red wine aroma compounds will be used for the creation of calibration curves, which will allow for quantification.Statistical analysis.The effect of varying SLF densities on grape juice pH, degrees Brix and TA, and on the total anthocyanins, total phenolics and tannins of the wines will be investigated with a regression analysis. The effect of the cage on these variables will be analyzed with ANOVA at alpha = 0.05; in the presence of significant differences, we will use post hoc tests to identify differences between treatment pairs.Methods for objective 2:The SLF economic decision levels will be calculated following the procedure described in Pedigo and Rice (2009) as follows:·Estimation of the yield loss per insect.This information will be obtained from objective one after quantifying the loss in yield from vines exposed to different SLF densities (insects per vine). From the regression equation obtained above, we will extract the yield loss per number of insects (b) to calculate the economic decision levels.·Determination of the gain threshold.The gain threshold is the amount of damage, yield loss or wine quality loss that justifies insect management; it will be calculated as follows:Gain threshold = (Management cost in dollars per acre)/(Market crop price in dollars per ton).The SLF management costs per season per acre will be estimated using spray records and other related information from vineyards that have been affected by SLF in the quarantine zone of Pennsylvania. A grape growers' survey will be developed to obtain the following information: number of years with SLF infestation, spray program to control SLF nymphs and adults (products, doses, frequency of applications, equipment used, cost of the products). Cost of labor (hours for insect scouting and product application) per area, number of tons per acre, and crop price per ton.·Determination of the loss that can be avoided by SLF management.We predict that opportune insecticide applications will prevent all loss that SLF may cause to vineyards; therefore, for this parameter, we will use a value of 1 (Pedigo and Rice, 2009).·Calculation of the Economic Injury Levels (EIL).Using the information described above, the EIL will be calculated as:EIL = [(Gain threshold (tons/acre)) / (loss per insect*Amount of loss avoided)].The Economic decision levels will be set lower than the EIL. For instance, 75% or 80% lower than the EIL to be conservative.Methods for objective 3:The damage boundary is defined as the lowest level of injury where damage can be measured (Pedigo and Rice, 2009). In this study, damage will be measured as yield loss and wine quality loss from vines exposed to various levels of SLF infestations as described in objective 1. The damage boundary is usually lower than the EIL, and damage below the boundary level does not require control (Pedigo and Rice, 2009).Efforts to improve knowledge of the target audience: The project PIs have extension appointments and meet regularly with grape growers in person and virtually to identify current needs and to share the results of our research projects. In addition to our meetings, the team will prepare an extension article with non-technical language targeted to grape growers and stakeholder.Evaluation of the project:OutcomeEvaluation1.We identify SLF densities that reduce grapevine yield and/or reduce wine quality.2.Based on experimental information of the effect of different insect densities on grapevine yield and wine quality, combined with data of SLF management costs, we estimate action thresholds for the management of this insect.3.We identify, experimentally the lowest number of SLF that decreases plant yield or reduces wine quality.4.The PIs will disseminate the results of this projects in various meetings and will develop short surveys to document the change in knowledge by the audience.

Progress 09/01/24 to 08/31/25

Outputs
Target Audience:The target audience of this project is grape growers, winery owners, extension personnel, scientists, and the general public. During the second year of this project, the PI participated in a variety of extension and outreach activities that reached 611 people who belonged to these groups. Details of these activities are presented in this report under the "Other Products" section. Changes/Problems:We requested and obtained a no-cost extension of the grant to finish the remaining work. We needed more time to complete the wine chemistry analyses and to obtain more responses from our growers' survey to estimate the spotted lanternfly management costs. This survey is key to estimating economic thresholds. What opportunities for training and professional development has the project provided?This project integrates knowledge of Entomology, plant physiology, and Food sciences. Everybody involved in the project has grown their expertise by working on this interdisciplinary team. Additionally, we have a graduate student of entomology, Sukhman Sigh, associated with this project, who has gained significant skills and knowledge in entomology, viticulture, and enology. Our technician for the first two years of the project, Taran Rowles, is now a Master's student in Plant Science at Penn State. This project provided Taran with important research experience to succeed in graduate school. How have the results been disseminated to communities of interest?The results of this project have been disseminated to grape growers and winery owners through in-person talks, workshops, and online webinars. The PI of the project has an extension appointment and has access to a listserv of grape growers and winery owners; the talks and workshop have been part of larger educational programs related to viticulture. Our audience has been informed of these educational opportunities using email, Facebook, and in-person invitations. Dissemination of the project's results to extension educators has been done by giving talks to already established annual training programs at Penn State University. Extension educators are contacted by email to make them aware of these training opportunities. Dissemination of information to scientists has been done by participating in regular spotted lanternfly meetings and workshops organized by USDA-APHIS and by associated scientists. Dissemination of results to the general public has been done by making digital educational content available online (talks, videos, and written articles) on our Penn State Extension Website and the New York IPM Center. On October 17, 2024, the PI presented the preliminary results of this project in a talk as part of a two-day conference organized by USDA-APHIS. Talk title: "Development of action thresholds for managing spotted lanternfly in winegrapes." Spotted lanternfly research and technology development meeting. Wooster, OH, Oct 17, 2024. The audience was ~63 scientists. On December 10, 2024, the PI presented the preliminary results of this project in a talk titled: "Update on the development of economic thresholds for managing spotted lanternfly in vineyards." Annual virtual Conference of the Northeast IPM Center. Dec 10, 2024. The audience was ~61 scientists, and the talk is available online at: https://www.northeastipm.org/about-us/publications/ipm-online-conferences/2024-northeast-integrated-pest-management-research-update-conference/ On February 5th, 2025, the PI presented the preliminary results of this project in a talk titled: "Effects of spotted lanternfly feeding on grapevines." As part of the Eastern New York Spotted Lanternfly Workshop, organized by the New York IPM Center. The audience was ~43 grape growers. On March 1, 2025, the PI presented the preliminary results of this project in a talk titled: "Effects of spotted lanternfly feeding on grapevine yield and juice/wine chemical parameters" as part of the 2025 spotted lanternfly summit organized by the New York IPM center. The audience consisted of ~311 participants, including extension educators, scientists, and government agents. On April 4th, 2025, the PI presented the preliminary results of this project in a talk titled: "Spotted lanternfly extension update" as part of the Spring 2025 update for extension educators organized by Penn State Extension. The audience was 133 extension educators. What do you plan to do during the next reporting period to accomplish the goals?This project was carried out over three years to assess the effect of lanternfly feeding on a perennial fruit crop (vineyard). This proposal supported the last two years of the project. The field part of the project was finalized this year, but we still have samples to analyze in the lab. In the next reporting period, we will present the results obtained from spotted lanternfly infestations on wine quality parameters. Additionally, we will present an estimation of spotted lanternfly management costs in vineyards after we finalize our growers' survey. We will integrate the effect of insect feeding on yield loss, plant health, juice chemistry, and management costs to suggest management thresholds in vineyards.

Impacts
What was accomplished under these goals? The spotted lanternfly is an invasive insect pest that has become a threat to grape production in the U.S. These insects must be managed to keep vineyards productive and in good health, but there is no knowledge of the number of insects per vine that should trigger management actions. During the second year of the project, we quantified the effects of spotted lanternfly feeding on grapevine yield and juice chemical characteristics that are important for flavor and quality; these included pH, sugar concentrations, acidity, concentration of phenolics, and tannins. Additionally, we quantified leaf and petiole mineral concentrations from grapevines infested with different insect numbers to determine if lanternfly feeding would affect plant nutrient uptake. Our results indicate that management efforts should be focused on controlling adult spotted lanternfly populations because these are more damaging than nymphs. Cabernet franc grapevines infested with lanternfly adults exhibited a decrease in yield that ranged from 4 to 58% during the second year of consecutive infestation. In the third year of consecutive insect infestation yield decreased from 5.3 to 79%. For Chardonnay, yield decreased between 3.7 and 55.25% in the second year and between 5.3% and 80.16% in the third year of consecutive insect infestation. Our preliminary estimations suggest that consecutive feeding for two months per season during two growing seasons (years) of one lanternfly adult per two plants is the maximum acceptable pest level that can be tolerated, given the cost of controlling the pest. These calculations will be improved as we collect more data from our growers' survey to determine the insect management costs. These results represent an extreme scenario of long-term pest feeding with no intervention and were calculated based on yield loss without accounting for reductions in juice quality.

Publications

  • Type: Peer Reviewed Journal Articles Status: Published Year Published: 2025 Citation: Pinto A.F., Eshenaur B.C., Acevedo F.E., Calixto, A.A., Centinari M., Gomez M.I. (2025). Assessing the potential economic impacts of spotted lanternfly (Lycorma delicauta, Hemiptera: Fulgoridae) infestations on grape production in New York State. Journal of integrated pest management 16 (1): 2; pmae039. https://doi.org/10.1093/jipm/pmae039


Progress 09/01/23 to 08/31/24

Outputs
Target Audience:The target audience of this project is grape growers, winery owners, extension personnel, scientists, and the general public. During the first year of this project, the PI participated in a variety of extension and outreach activities that reached 524 people who belong to these groups. Details of these activities are presented in this report under the "Other Products" section. Changes/Problems:We may need to request a no-cost extension of the grant to finish the remaining work, but the team will assess that in the upcoming months. What opportunities for training and professional development has the project provided?This project integrates knowledge of Entomology, plant physiology, and Food sciences. Everybody involved in the project has grown their expertise by working on this interdisciplinary team. Additionally, we have a graduate student of entomology, Sukhman Sigh associated with this project who has gained significant skills and knowledge in entomology, viticulture, and enology. How have the results been disseminated to communities of interest?The results of this project have been disseminated to grape growers and winery owners through in-person talks, workshops, and online webinars. The PI of the project has an extension appointment and has access to a listserv of grape growers and winery owners, the talks and workshop have been part of larger educational programs related to viticulture. Our audience has been informed of these educational opportunities using email, Facebook, and in-person invitations. Dissemination of the project's results to extension educators has been done by giving talks to already established annual training programs at Penn State University. Extension educators are contacted by email to make them aware of these training opportunities. Dissemination of information to scientists has been done by participating in regular spotted lanternfly meetings and workshops organized by USDA-Aphis and by associated scientists. Dissemination of results to the general public has been done by making digital educational content available online (talks and written articles) on our Penn State Extension Website. What do you plan to do during the next reporting period to accomplish the goals?This project needs to be carried out over several years to assess the effect of lanternfly feeding on a perennial fruit crop (vineyard). In the next reporting period, we will present the results obtained from spotted lanternfly infestations in the growing season of 2024. We will report effects on yield, pH, sugar concentrations, acidity, concentration of phenolics, tannins, and leaf/petiole mineral concentrations. Additionally, we will present an estimation of spotted lanternfly management costs in vineyards. We will integrate the effect of insect feeding on yield loss, plant health, juice chemistry, and management costs to suggest management thresholds in vineyards.

Impacts
What was accomplished under these goals? The spotted lanternfly is an invasive insect pest that has become a threat to grape production in the U.S. These insects must be managed to keep vineyards productive and in good health, but there is no knowledge of the number of insects per vine that should trigger management actions. During the first year of the project, we quantified the effects of spotted lanternfly feeding on grapevine yield and juice chemical characteristics that are important for flavor and quality; these included pH, sugar concentrations, acidity, concentration of phenolics, and tannins. Additionally, we quantified leaf and petiole mineral concentrations from grapevines infested with different insect numbers to determine if lanternfly feeding would affect plant nutrient uptake. Our results indicate that management efforts should be focused on controlling adult spotted lanternfly populations because these are more damaging than nymphs. Our preliminary data indicate that under our experimental conditions, grapevines can withstand feeding by up to 300 nymphs for about two months without major effects on plant health or juice quality. However, grapevines infested with more than 40 adults show a reduction in yield and juice quality characteristics. We need more data to calculate the appropriate number of insects that should trigger management actions, but this should be obtained in the following year of the project. These results are very important for grape growers, winery owners, and winemakers due to the direct effects of spotted lanternfly feeding on yield and grape juice quality.

Publications