Recipient Organization
UNIVERSITY OF GEORGIA
200 D.W. BROOKS DR
ATHENS,GA 30602-5016
Performing Department
Entomology
Non Technical Summary
Pecan growers face new insect and mite pests each year. Effective control methods will developed for these emerging problems so that the pecan trees will retained their productivity. Insect and mite pest populations become tolerant to existence chemical controls and new chemical controls will be developed through research to find efficacious alternatives to insecticides and miticides that are losing efficacy. Biological controls, including host plant resistance are fast becoming effective alternatives for inset and mite control in pecan and research will develop methods for conservation of the biocontrol agents and evaluation of HPR in pecan cultivars. Field research with randomized and controlled experiments are the most effective method for finding new control methods for pecan insects and mites as none of the pests can be reared in the lab and field populations of the insects and mites at the experiment station farms have the same tolerance and/or susceptibility to chemical and biological controls. This project outlines the field research methods needed to find new and efficacious controls of pecan insect and mite pests.
Animal Health Component
75%
Research Effort Categories
Basic
25%
Applied
75%
Developmental
(N/A)
Goals / Objectives
1. Improve monitoring methods for pecan arthropod pests.2. Improve biological and chemical control methods for pecan arthropod pests.3. Develop decision tools for accurate spray timing for growers.
Project Methods
Obj. 1: Aphids and Aphidophaga - Fan traps will be developed to collect aphids and aphidophagous insects from the tree canopy by pulling samples of air from the heights of 20 feet through a fine meshed screen. The construction and early results of the fan traps has been reported in the previous pecan Hatch project. The traps will be tested and reconstructed for use in pecan orchards over the next five seasons to improve the ease of the collection of samples and waterproofing and portability. Small solar powered fan-light traps will be tested in the tree canopy for their effectiveness in collecting aphids and aphidophagous insects. Prionus root borers - Pheromone traps for prionus root borers will be improved by adding a solar-powered LED light to the trap.Obj. 2: Insect and Mite Controls: Biological Control - Ant repellents (methyl anthranillate, methyl myristate and methyl carbitol) and insecticide treated baits will be evaluated in replicated field trials to enhance natural enemies in the intercrops by removing ants from the plants. The intercrops crops - crimson clover, hairy vetch and joint vetch - will be sown in the fall to provide alternate prey aphids for the predators in the spring. Red imported fire ant and argentine ant protect the alternate prey aphid colonies and actively remove predators from the aphid colonies. Repellents will be evaluated on potted plants in the greenhouse and in the pecan orchard by setting out aphid infested plants in ant infested areas of the orchard with and without repellents. Direct observations will be taken of behavior of ants, aphids and aphidophagous insects will be recorded by the established methods. Ant control will be evaluated in a field trial with "Ants Present" and "Ants Controlled" as main plots and with intercrops as subplots with four replications in a split black design. Ants will be controlled in the "Ants Controlled" main plots with insecticide treated baits and mound drenches with carbaryl. Subplot treatments are: 1. mowed sod; 2. crimson clover; 3. hairy vetch; 4. crimson clover + hairy vetch; 5. joint vetch. Abundance of ants, aphids and aphidophagous insects will be evaluated from field samples of intercrops and pecan trees.Insect and Mite Controls: Chemical Control - New chemical controls will be evaluated as treatments and compared to standard materials and a non-treated control in robust, randomized, replicated field trials to determine the impact of each treatment on insect control, non-target pests and beneficial insects and pecan nut yield and quality for newly registered insecticides on pecan. As examples, Sivanto is a systemic insecticide and can be applied as a foliar spray or as a soil drench, shank or drip application and not one of these methods has been tested for efficacy in pecan. OSII and ABBA Ultra are two new materials that integrate well with natural enemies and costs are quite variable from a $6 to $27 per spray per acre The research will be conducted at orchards of the Coastal Plain Experiment Station and cooperating pecan growers. The orchard at the Southeast Branch Station at Midville, GA and the Ponder Farm in Tifton will have the replicated field trials with 4 plots per replication and two 80' trees per replication at Midville and four 30' trees per replication at Ponder Farm. The target pest at the Midville Farm are middle to late season nut pests. Chemicals supplied by industry cooperators will be compared for efficacy to grower standard controls when applied to large demonstration plots on commercial orchards and evaluated post-treatment for insect injury. Chemical industry partners will supply additional support with funding and/or spray materials for the trials. Similar trials with new insecticides will be conducted each summer over the duration of the project with different materials in similar plot layouts. All the new insecticides/miticides can be applied to the foliage with air-blast sprayers and any difference in the application costs will be due to the number of sprays and the spray volume needed for control. Evaluations will measured season-long with counts of insect and mite population levels and injury levels and damage to the nut production and nut quality at harvest. Insects and mites are monitored at each site one time per week throughout the season with lea samples, light traps, weevil traps and pheromone-baited traps. Sprays are applied when the target pest is found at a significant population level and then treatments are evaluated by sampling the foliage and pecan nuts for insects, mites and injury after the sprays are applied.Pecan nut yield and quality are measured in all trees in November and December. The results are then interpreted to compare the economy of each treatment by weighing efficacy and impact on yield and quality against the costs of the control methods. All sprays will be applied with the same sprayer at both locations and at the same spray volume (100 gal/acre), pressure (180 psi at the pump), and tractor speed (1.9 mph) for all treatments. Both locations have drip irrigation so that one treatment of Sivanto at the maximum labelled rate applied to the soil drench adjacent to the irrigation emitters will be tested against the foliar sprays targeted against black and yellow pecan aphids. The plots at the farms will be maintained with conventional fertilizers, herbicides and mowing and fungicides so that the differences between the plots can be attributed to the insecticide/miticides treatments. A nontreated check is the first treatment (CHCK). Two standard treatments are applied. Standard 1 (STD1) is a combination of Portal plus Beleaf for foliage pest control. Standard 2 (STD2) is Intrepid alone in early season and Intrepid plus Mustang Max in late season. The target pests for each treatment are: prevention of aphids and mites for chitosan (OSII); all nut pests for Gladiator (GLAD); aphids for Sivanto (SIVEA and SIVSP); mites for abermectin (ABBA); pecan nut casebearer and hickory shuckworm for Intrepid Edge (INTED). Chitosan is applied ever three weeks as a preventative treatment. Emitter adjacent application of Sivanto is applied in mid-May as a systemic preventative treatment for aphid control. All other treatments spray timing will depend on the results of the weekly scouting reports. Economic analysis outlined in a previous paper (Dutcher et al 2006) will be used to develop decision tools for growers for the selection of treatments based on costs and efficacy. Time table the research is as follows: April 2015 - start chitosan regimen; May, 2015 - INTED and STD2 for PNC, SIVEA for aphids; June-Sept, 2015 scout, spray and evaluate all treatments; Aug-Sept, 2015 - multiple pecan weevil, stink bug hickory shuckworm sprays of GLAD, STD2 and CHCK at Midville Farm.Obj. 3 Decision Tools - Pecan nut casebearer pheromone baited traps will be monitored one time per week from April 1 to June 15 along with nut inspections for injury and catkin samples for predatory and parasitoid insects to correlate with daily degree day accumulations at 4 locations from Thomasville, Tifton, Cordele and Perry, GA over five seasons to formulate a model to determine the treatment date based on weather and predator levels. The predators and parasitoids will be identified and the relative abundances will be compared across the sampling sites and related to pecan nut casebearer injury. Hickory shuckworm light traps will be run and pecans will be sampled for oviposition injury and nut drop at the same 4 locations from May 15 to Aug. 15 each week and daily at Tift Co. to determine the flight activity and occurrence times for injury and nut drop of the summer population over five seasons.