Research Project: Integrated Approach to Manage the Pest Complex on Temperate Tree Fruits

Location: Temperate Tree Fruit and Vegetable Research

Project Number: 2092-22430-003-000-D
Project Type: In-House Appropriated

Start Date: Oct 26, 2020
End Date: Oct 25, 2025

Objective:
The long-term objective of this project is to provide the basic and applied information needed for the development and transfer of safe and environmentally sustainable tools or methods for management of arthropod pests of temperate tree fruits. Specifically, during the next five years we will focus on the following objectives: Objective 1: Develop and improve tools and approaches for early detection, prediction, and monitoring of arthropod pests and their natural enemies in temperate tree fruits. • Sub-objective 1A: Determine if pre-harvest commercial pear is an acceptable host for apple maggot fly. • Sub-objective 1B: Identify volatile attractants from pear trees for early detection of orchard-colonizing winterform pear psylla. • Sub-objective 1C: Identify the primary non-orchard habitats that are sources of orchard-colonizing winterform pear psylla. • Sub-objective 1D: Identify the thermal tolerances of brown marmorated stinkbug and Trissolcus japonicus to more accurately determine potential establishment and spread. • Sub-objective 1E: Identify non-crop plants that are sources of orchard-colonizing vectors of the X-disease Phytoplasma. Objective 2: Provide basic and applied information of the physiology, biochemistry, behavior, and landscape ecology of arthropod pests and their natural enemies necessary to develop new or improve existing integrated pest management strategies in temperate tree fruits. • Sub-objective 2A: Determine the thermal kinetics of apple maggot. • Sub-objective 2B: Determine functions of proteins key to codling moth reproduction, development, physiology, and behavior. • Sub-objective 2C: Determine extent of cryptic species diversity in minute pirate bug fauna of the western U.S. in both orchard and non-orchard habitats. • Sub-objective 2D: Examine non-target effects of herbicides on key natural enemies of arthropod pests of apple and pear. • Sub-objective 2E: Identify genes and proteins that are key to acquisition and transmission of X-disease Phytoplasma by leafhopper vectors. Sub-objective 2F: Identify plant-based volatile attractants or repellents of leafhopper vectors of X-disease Objective 3: Develop new or improved integrated management strategies to control arthropod pests in temperate tree fruits. • Sub-objective 3A: Improve control strategies for apple maggot in organic waste. • Sub-objective 3B: Develop pest management strategies for cherry fruit fly that incorporate newer and less toxic insecticides. • Sub-objective 3C: Model the relationship between estimated populations of Trechnites adults and rates of parasitism of pear psylla. • Sub-objective 3D: Develop management practices that increase the retention time of released natural enemies of arthropod pests of apple. • Sub-objective 3E: Develop new or improved management tools to control pathogens and vectors of little cherry disease.

Approach:
Objective 1. Sub-objective 1A: Behavioral and development bioassays will determine if pear is an acceptable host for apple maggot and whether pear fruit is a potential source for apple maggot introduction in export countries. Sub-objective 1B: Volatiles will be identified from pear trees using GC-MS, and electroantennogram, behavior assays, and field trials will determine whether isolated volatiles elicit responses from pear psylla. The resulting lure will be used to monitor pear psylla populations. Sub-objective 1C: Gut content analysis will be used to identify where pear psylla overwinter. Sub-objective 1D: Differential scanning calorimetry will be used to determine the thermal capacity of brown marmorated stink bug and its parasitoid, and to identify climates that are favorable to their establishment and spread. Objective 2. Sub-objective 2A: The thermal death kinetics of apple maggot will be determined using differential scanning calorimetry and micro-respiration. Results will be used to improve management of apple maggot in commercial composting facilities located in apple maggot free zones. Sub-objective 2B: Candidate codling moth genes will be silenced using CRISP-Cas9 and behavior assays will be used to identify the function of the silenced genes. Results will identify viable gene-targets for use in codling moth control. Sub-objective 2C: Morphology of Orius will be examined to identify diagnostic traits and possible new species, and a diagnostic key will be developed to identify species belonging to the group of important natural enemies. Sub-objective 2D: Standard laboratory bioassays will be used to examine the effects of herbicides and additives on mortality and fecundity of the key orchard predators Galendromus occidentalis, Amblydromella caudiglans, and the European earwig. Results of this study will allow growers to adapt orchard floor management strategies that conserve key natural enemies. Objective 3. Sub-objective 3A: Laboratory experiments will be conducted to determine whether 100% of apple maggot flies are killed by exposure to 55 degrees, the temperature found in commercial composting operations. Sub-objective 3B: Standard bioassays will be used to determine whether the insecticides tolfenpyrad, pyrifluquinazon, azadirachtin, and pyrethrins kill or reduce fecundity of cherry fruit fly and can be used as an alternative to spinosad as an attract and kill approach to fruit fly management. Sub-objective 3C: Adult populations of Trechnites will be monitored using traps and psylla parasitism rates will be monitored by dissection of psylla or by PCR and the relationship between adult populations of Trechnites and actual parasitism rates will be modeled to allow growers to incorporate biological control provided by Trechnites in psylla management practices. Sub-objective 3D: Field studies will be conducted in commercial apple orchards to test whether nutritional supplements including Typha spp. pollen or brine shrimp cysts increase the retention of released natural enemies, Orius insidiosus, Chrysoperla rufilabris, or Cryptolaemus montrouzieri. Results will improve augmentative biological control in commercial orchards.