Project Number: 8042-22000-288-03-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jul 1, 2018
End Date: Jun 30, 2019
Overall research objective is to gain knowledge necessary for sound pest and resistance management practices for CPB using alternative/selective insecticides including, but not limited to: Trident [Btt], Exirel [cyantraniliprole], and Blackhawk [spinosyn]). Objective 1: Investigate baseline geographic variability in tolerance of CPB to alternative insecticides in order to predict the rate at which resistance might develop (UMD/Hawthorne Lab). Objective 2: Determine field efficacy of alternative insecticides on CPB and potential non-target effects on natural enemies of CPB (ARS, VT, and UMD/Dively Lab Objective 3: Evaluate potential sub-lethal effects of alternative insecticides on CPB predators (ARS). Objective 4: Field assessment of alternative insecticides on biological control of CPB (ARS and VT).
Objective 1: Determine field efficacy of alternative insecticides on CPB and potential non-target effects on natural enemies of CPB: Conduct field evaluations of efficacy on CPB, and evaluate the residual toxicity of various selective insecticides for CPB (adults and larvae), spined soldier bug (adults and nymphs), spotted pink lady beetle (adults and larvae), and Lebia ground beetle (adults and larvae). These species are available at Beltsville, the first two already in laboratory rearing. Field plots will be arranged in a randomized block design with four replicates per treatment and CPB eggs, larvae, and adults will be monitored over time. Bioassays using excised leaves from these field experiments will be used to determine residual efficacy of materials on CPB and its predators 24 h, 7 d and 14 d after foliar application (ARS). Bioassays will be carried out using a method similar to that used in Wimer et. al. (2015). Objective 2: Evaluate potential sub-lethal effects of alternative insecticides on CPB predators: Assess mobility, feeding rates, longevity and fecundity of spined soldier bug, spotted pink lady beetle, and Lebia ground beetle after exposure to sublethal doses of various alternative insecticides (determined in Objective 1, materials provided by VT and UMD/Dively Lab). Mobility will be assessed by isolating pre-exposed predators to a 15 cm diameter Petri dish (with species-appropriate food source) where they will be observed over time using a video recording device and ImageJ to estimate distance traveled (Meijering et al. 2012). Feeding rates will be assessed using a method similar to Weber et al. (2008), where pre-exposed predators will be offered CPB larvae in order to determine their rate of prey consumption over 28 days. Longevity and fecundity will be determined by holding pairs of pre-exposed predators (with species-appropriate food source) and observing twice weekly for mortality and number of eggs laid over time. Objective 3: Field assessment of alternative insecticides on biological control of CPB: Compare CPB and natural enemy populations in potato managed with alternative insecticide rotations versus a conventional rotation in order to estimate biological control potential. Potato plots established in Virginia and Maryland (at least 4 plots, at least 0.25 acre in size) will be subdivided and randomly assigned a conventional pest management spray program (Huseth et al. 2014) or a spray program designed for conservation biocontrol (using only alternative insecticides). These subplots will be monitored for CPB and natural enemies weekly until harvest, after which yield will be assessed by estimating pounds of marketable potatoes per row/ft. Assessments of CPB density will be conducted by counting the number of small and large larvae found on 10 arbitrarily chosen potato stems in four locations of each subplot (Wimer et al. 2015). Timed observations will be conducted in four locations of each subplot to record daytime predator presence.