Location: Crop Improvement and Protection Research
Project Number: 2038-30400-001-000-D
Project Type: In-House Appropriated
Start Date: Oct 1, 2025
End Date: Sep 30, 2030
Objective:
Objective 1: Develop new treatments based on controlled atmosphere, sulfur dioxide fumigation, and new insecticidal organic volatile compounds as fumigants for control of postharvest pests on fresh and stored products.
Sub-objective 1.A: Determine effects of ultralow oxygen treatment on mortality of spotted wing drosophila in cherries and blueberries.
Sub-objective 1.B: Develop sulfur dioxide fumigation treatments for control of postharvest pests on fresh and stored products.
Sub-objective 1.C: Determine effective chlorobenzene fumigation treatments against stored product pests.
Sub-objective 1.D: Determine safe and effective chlorobenzene fumigation treatments for postharvest pest control on fresh commodities.
Objective 2: Develop improved knowledge of soil microbial communities, and strategies to reduce pest and disease pressure as alternatives to soil fumigants.
Sub-objective 2.A: Determine effect of metallic nanoparticle application rate on plant pathogen fitness and plant growth.
Sub-objective 2.B: Effect of metallic nanoparticle application on soilborne diseases, soil and crop microbiomes, and crop health.
Approach:
Sub-objective 1A: Ultralow oxygen (ULO) treatments will be evaluated for efficacy against spotted wing drosophila eggs and larvae in blueberries and cherries. Infested blueberries and cherries with eggs and larvae will be exposed to ULO treatments with different O2 levels (50-500 ppm) for 2-4 days at a low temperature. Treated and untreated fruits with eggs and larvae will be reared to pupae and adults to determine efficacy of ULO treatments. Other options including SO2 fumigation will be considered if ULO treatment alone does not achieved effective control of the pest.
Sub-objective 1B: Large-scale laboratory SO2 fumigation treatments of 350-400 kg wheat grains will be conducted to demonstrate efficacy of SO2 fumigation against stored product insects and determine parameters for developing commercial scale SO2 fumigation trials. Then, commercial scale SO2 fumigation trials will be conducted to demonstrate commercial feasibility and efficacy.
Sub-objective 1C: Ham mites and navel orangeworm will be subjected to chlorobenzene fumigation to develop alternative treatments. Different life stages of the two pests will be fumigated in small scale fumigations to determine effective treatments against all the life stages. Large scale tests will be conducted to verify efficacy.
Sub-objective 1D: Chlorobenzene fumigation will be conducted against western flower thrips and false spider mites on fresh products to determine efficacy against the pests and safety to fresh product quality. Both species will be fumigated at a low temperature with different doses to chlorobenzene in jars for 24-48 h to determine effective treatments. Selected effective treatments will be conducted in larger scale fumigations with pests and fresh products to verify efficacy and evaluate possible impact on postharvest quality of fresh products. After fumigation, fresh products will be stored for 2-4 weeks and then evaluated for postharvest visual quality.
Sub-objective 2A: Bulk and nanoparticle copper oxides will be tested for effects on the plant pathogens Verticillium dahliae and Fusarium oxysporum and effects on growth of strawberry and lettuce plants. Multiple concentrations of copper oxide will be evaluated to identify the optimal dose that reduces pathogen growth and has no negative effect on crop growth. Inhibitory effects on pathogens will be determined based on in-vitro inhibition of radial growth on standard microbiological growth media. Effects on crop growth will be determined by applying different concentrations of copper oxide to plants and measuring fresh and dry weight at crop maturity.
Sub-objective 2B: The optimal dose of copper oxides identified in Sub-objective 2A will be applied on lettuce and strawberry plants grown in pathogen contaminated soil to evaluate impacts on soilborne diseases and crop microbiomes in greenhouse. Disease severity will be measured on a weekly basis and crop microbiomes will be characterized using next-generation sequencing of rhizosphere soil and plant DNA. Relationships between, disease severity, copper oxide application, and changes in crop microbiomes will be determined using univeriate and multivariate statistical methods.