Location: Application Technology Research
Project Number: 5082-21000-001-048-A
Project Type: Cooperative Agreement
Start Date: Sep 1, 2021
End Date: Jul 31, 2025
Cooperator will conduct research to address the following objectives: 1) Predict the risk of infestations in orchard and nursery crop systems through improved understanding of AB biology and ecology, 2) Implement comprehensive management strategies, and 3) Transfer research-based information to stakeholders.
To address objective 1, flood and drought stress will be imposed on experimental trees. Drought and flood conditions will be maintained for 21 d and beetle attacks on each tree will be quantified every 3 d. Stems from attacked trees will be returned to laboratories at the end of the experiment and stored at 4°C until dissection. Adults, brood (i.e., eggs, larvae, pupae), and presence of fungal gardens will be quantified to assess colonization success. Tissue samples will also be taken to quantify ethanol in stem tissues. Objective 1 will also be addressed by inoculating apple trees with fire blight to assess the influence of infection on ethanol production and ambrosia beetles. Count data of attacks, specimens, and fungal gardens will be determined. Similarly, experiments will be conducted to assess the acquisition and transmission of fire blight by ambrosia beetles. Surface sterilized lab reared beetles will be exposed in vials to filter paper discs treated with a highly virulent strain of fire blight. Fire blight acquisition on the beetle cuticle will be determined. Transmission assays will also be conducted to determine if beetles can transmit fire blight to healthy trees. Objective 1 will also be addressed using tree and trap surveys on a biweekly schedule from early spring through fall to gain insight into the diversity of auxiliary fungi associated with ambrosia beetles and their galleries. To address objective 2, cooperators will test conventional and alternative insecticides under field conditions. Cooperators will conduct rapid screening in two tiers to identify novel and previously untested products with efficacy comparable to permethrin and bifenthrin (currently the most effective insecticides). Attacks on each bolt will be counted for 21 d after deployment. Afterwards, bolts will be returned to participating labs for temporary storage until being dissected to identify and quantify beetle, brood, and the presence/absence of fungal gardens. Repellents will also be tested against as part of objective 2. In particular, repellent compounds and delivery methods will be screened for efficacy using cored, ethanol-filled bolts. Pouch-style emitters will be hung next to bolts vs. an impregnated wax-based paste applied on bolt surfaces. Bolts will be deployed for 14 d, and then dissected to compare ambrosia beetle attacks and species recovered. The most effective repellent compound(s), and optimal lures will be integrated to test their capability to reduce attacks on trees representing the three crop types. Trees will be irrigated with ethanol to ensure their attractiveness to ambrosia beetles. Objective 3 will also be addressed by testing plant defense elicitors for inhibiting ambrosia beetle attacks and/or colonization using potted species/cultivars of apple, pecan, and dogwood under flood stress regimes. Following the field experiment, trees will be dissected to identify and quantify adult and brood ambrosia beetles within the galleries. To address objective 3, cooperators will conduct traditional in-person meetings, web-based approaches (blogs,YouTube, social media), and outreach publications.