Location: Southern Horticultural Research Unit
2020 Annual Report
Objectives
1. Develop environmentally friendly strategies for the control of small fruit diseases based on chemical, biological, and/or cultural control by conducting basic and applied research on the epidemiology, pathogenesis, and genetics of small fruit pathogens and their hosts.
1.1. Assess the effect of supplemental lights (LED, UV-B) on anthracnose pathogen growth in culture and on infection of greenhouse grown strawberries.
1.2. Assess the use of cover crops to reduce root rot pathogen populations in blueberry fields.
1.3. Develop a protocol to identify anthracnose resistant strawberry seedlings using non-viable culture filtrates of the anthracnose fungi.
2. Expand the scope and efficacy of plant pathogen sanitation technologies at multiple disease management scales involving propagation, general sanitation, and seasonal irrigation water treatment for ornamental production systems.
2.1. Evaluate spatial distribution of bacteria causing bacterial gall of Loropetalum in commercial nurseries and its association with stem cuttings used for propagation.
2.2. Determine rate activity responses for major commercial disinfestants against bacterial, fungal and viral plant pathogens.
2.3. Develop integrated preventive and reactive disease management strategies to control Pseudomonas, Colletotrichum, and Phytophthora in propagation facilities.
2.4. Develop concentration-time (CT) rates with water quality and temperature as covariates for treatment of Phytophthora nicotianae in irrigation water.
2.5. Model the relationship of seasonal dispersal of Phytophthora zoospores in recycled irrigation water with plant disease symptom development and weather conditions.
3. Discover, test, and develop new conventional and organic controls for the Spotted Wing Drosophila (SWD) and develop improved bee-safe practices for their application.
3.1. Discover and test erythritol, its derivates, essential oils, and insect growth regulators (IGRs) for control against SWD and other serious horticultural insect pests.
3.2. Test for additive or synergistic activity from combinations of select compounds from sub-objective 3.1 with biopesticides.
3.3. Test health safety of compounds from sub-objectives 3.1 and 3.2 to honey bees and important native bee crop pollinators.
4. Develop new management and conservation techniques for honey bees and important wild native bee pollinators for small fruit, vegetable and ornamental crop production.
4.1. Collect cocoons from trap-nests for managing orchard bees and chimney bees as fruit pollinators.
4.2. Develop and implement a pollinator release program.
4.3. Assess effects of common and new insecticides on these and other native bee pollinators of horticultural food crops.
4.4. Assess the use of soybean cultivars as bee forage for native and honey bees during the summer dearth along the Gulf Coast.
Approach
Evaluate influence of multiple light spectra, including UV-B light, on strawberry plant growth and as a way to inhibit germination and growth of anthracnose pathogens, thereby reducing disease. Assess effect of rotational cover crops (legume, brassica and grass), fallow and chemical treatments on Phytophthora populations in the soil and on severity of root disease on blueberry in replanted fields. Develop plant screening protocols using non-viable filtrates with presumed toxins of anthracnose pathogens to identify anthracnose resistance in strawberry seedlings. Sample for and analysis for distribution patterns of the bacterial knot pathogen on Loropetalum nursery stock to develop strategies for propagating pathogen-free plants. Identify differences in pathogen sensitivities, substrate demand loads and environmental factors that favor and interfere with disinfestant activity for several disinfestant chemical classes. Evaluate what combination of disease control practices allow for minimum levels of integrated management needed to control several major pathogens in woody plant propagation. Identify water quality and environmental factors that require adjustment in disinfestant concentration exposure to maintain control of Phytophthora in irrigation water. Monitor Phytophthora levels in pond water, the resulting disease progress on woody plants irrigated with the pond water and correlate these with favorable environmental conditions. Investigate how chemical formulation affects the activity of sugar alcohol pesticides, essential oils, and insect growth regulators applied to different stages of the spotted-wing Drosophila (SWD) fly. Identify what combination of chemicals previously tested by this research unit provide maximum mortality of SWD. Evaluate health effects on honey bees, orchard bees, chimney bees, and southeastern blueberry bees exposed to the chemicals evaluated by this research unit for SWD control. Collect orchard bees and chimney bees from across the southern U.S., establish them by commercial blueberry fields in Mississippi, determine their suitability as a pollinator and develop colony rearing practices. Establish orchard bee and chimney bee colonies near cooperating blueberry fields and monitor seasonal dispersal behaviors. Evaluate health effects on bee pollinators exposed to various insecticides, then assay for gene activity, enzyme activity and protein profiles. Evaluate the bloom period of soybean cultivars planted at several dates and monitor the feeding activity and health of native and honey bees.
Progress Report
This new project replaced project #6062-21420-003-00D, "Production and Disease and Pest Management of Horticultural Crops." Please refer to project #6062-21430-003-00D for additional information.
ARS researchers in Poplarville, Mississippi, substantiated that erythritol is synergistic with a commercial microbial-based biopesticide (Grandevo®) by doubling the effectiveness against spotted-wing Drosophila fly in laboratory and field research.
An ARS researcher in Poplarville, Mississippi, established study with supplemental lighting to test the effect of LED light on strawberry growth and anthracnose disease suppression, caused by Colletotrichum gloeosporioides. Cover crop plots were established in a previous blueberry field with a history of Phytophthora root rot from which infected blueberry plants were removed.
Accomplishments
