Location: Temperate Tree Fruit and Vegetable Research
Project Number: 2092-22000-022-032-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Mar 1, 2023
End Date: Jul 15, 2025
Objective:
Objective 1. Identify generalist predators of potato psyllid and beet leafhopper occurring on non-crop host refuges.
Objective 2. Investigate overwinter predation on pear psylla, beet leafhopper, and potato psyllid.
Objective 3. Disseminate information about predators and biological control to growers and stakeholders and begin incorporating this information into pest forecast models.
Approach:
Objective 1: Non-crop hosts of potato psyllid and beet leafhopper will be sampled for predators spring, summer, and autumn in stands of matrimony vine, bittersweet nightshade, field bindweed, and longleaf groundcherry. Various annual hosts such as Datura and coyote tobacco will be sampled during summer as they germinate. Predators on beet leafhopper hosts will be collected from annual mustards in early spring, and kochia and Russian thistle from mid- to late-summer as they become available. Predators will be sampled using a D-vac insect collection device, or by using a standard beet sheet. In addition, plant clippings will be collected from each stand and extracted in Berlese funnels. Prey and predatory taxa will be sorted, counted, and identified. Predator specimens will be assayed for presence of target DNA (potato psyllid or beet leafhopper) using PCR. A subset of predators will be processed for directed sequencing to detect insect DNA from predators’ guts.
Objective 2: Pear psylla and predators will be collected in December, January, February, and March from conifer shelter plants. Predators will also be extracted from cardboard sleeves placed on pear trees in autumn. Predators, including spiders, will be extracted from leaf and detritus collections from below winter hosts of potato psyllid or beet leafhopper into preservative using Berlese funnels and then identified based on morphological traits. A real-time PCR assay with pear psylla-specific PCR primers will be used to detect the presence of pear psylla DNA in predator guts. A subset of predators will be processed for directed sequencing to obtain a more complete dietary history of the predators.
Objective 3: Predators and non-crop habitats will be ranked by importance and these rankings will be provided to growers through industry newsletters and websites. Descriptions and photographs of important natural enemies will be forwarded to Extension cooperators for dissemination to interested growers. Because many natural enemy species regularly move between crop and non-crop habitats, identifying important species and the plant sources of those species will help us communicate to growers which specific predators of psyllids and leafhoppers are likely to be present in their fields on an annual basis. We will also begin to assess whether estimated predation in these habitats can be incorporated into models used to predict pest pressure and phenology.
