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2023 WA Tree Fruit Research Commission Grant Awards for Apple Crop Protection

Washington Tree Fruit Research Commission logo

Date: March 2023

Authors: Paige Beuhler and Ines Hanrahan

The WA Tree Fruit Research Commission approved $121,457 to help fund five (5) new Apple Crop Protection projects for 2023.

2023 New Apple Crop Protection Project Details

Project Title: Crop Protection Product Efficacy Testing for Codling Moth- Laboratory

Organization (s): Washington State University

PI (s): Curtiss, R.; Nottingham, L.; Northfield, T.

Total Funding Amount for All Years: $80,000

Length: 2 Years

Codling moth, the most important pest of apples worldwide, continues to need new tools for management. Mating disruption, the cornerstone of management programs, does not work without the integration of supplemental control measures. The ongoing struggle between growers and pests requires constant research to develop and test new solutions that effectively tip the scales in the growers’ favor. This project aims to establish a codling moth colony which will be available for use in new crop product testing, lab-test current and new conventional and organic materials and strategies’ effectiveness as CM control tactics, supply moths to researchers and companies to sustain outside funding, and update extension resources to include new product information.

Project Title: Phase 3: New Biocontrol Strains Against Fire Blight

PI (s): Doty, S.; DuPont, T.

Total Funding Amount for All Years: $30,072

Length: 2 Years

Since fire blight remains to be a major concern for the Washington State apple and pear industries and there is a strong demand for more effective control strains. In Phase 1 of this project, the team successfully isolated 40 new microbial strains with in vitro activity against E. amylovora. In Phase 2, they selected three strains for field trials in Wenatchee with one of these strains, 4RDLA, reducing fire blight infections as well as two products already used within the industry, Blossom Protect (organic) or Firewall (conventional). For this newly funded Phase 3 project, the team plans to repeat the field trial with 4RDLA and two new strains, #42 and #90,  that inhibited the growth of E. amylovora in vitro. They will then genome sequence and analyze #42 and #90, as well as two additional strains for subsequent testing. Finally, the team will repeat the field trial with strains  #42 and #91 if they perform well or test the additional sequenced strains.

Project Title: Functional Peptides as New Tools for the Control of Fire Blight

Organization (s): Washington State University

PI (s): Sabe, A.; DuPont, T.

Total Funding Amount for All Years: $29,994

Length:  2 Years

Current fire blight management relies on prevention of blossom infections with antibiotics and biopesticides and mineral compounds such as copper. Recent work has developed a novel approach using peptides for the control of plant diseases. Peptides are fragments of proteins with different activity characteristics, and some of them show more than one mode of action, for example antimicrobial activity and plant defense induction. These functional peptides have an advantage over other products, as they provide various modes of action in only one application.

The objective of this grant is to test the novel compound bifunctional peptide BP178, and its optimization for the control of fire blight infections in the field. The team will first determine the efficacy of the bifunctional peptide BP178 in controlling fire blight by means of (i) evaluating flower cluster infections weekly for three weeks starting from when symptoms become visible, (ii) enumerating the population levels of E. amylovora 1, 4, 7 and 11 days after inoculation, and (iii) evaluating the severity of shoot blight infections by measuring the length of the canker. They will then evaluate fruit marking, and then compare to the results obtained using either streptomycin (antimicrobial activity), Actigard (induction of plant resistance) or water (non-treated control).

Project Title: Pesticide Residues of Washington Apples

Organization (s): WTFRC

PI (s): Schmidt, T.

Total Funding Amount for All Years: $20,475

Length: 3 Years


With steadily increasing crop sizes, Northwest tree fruit producers are increasingly reliant on foreign markets to purchase their products at good prices. Current estimates are that Washington exports approximately 30% of its apple crop. Even though compliance with domestic regulations set by the US Environmental Protection Agency (EPA) regarding pesticide residues on fruit is rarely a concern for growers following application guidelines described on product labels, most foreign markets set their own Maximum Residue Levels (MRLs) for the same chemicals which are often more restrictive than EPA tolerances. As such, apple growers need information about residues left by each pesticide they use to determine if they need to modify their use patterns for those products to guard against potential violations of MRLs in those export markets. This project aims to determine chemical residues left by commonly applied pesticides on commercially grown Washington apples, and to then report the results broadly to the Washington apple industry in a timely manner.

Project Title: New Products for the Prevention and Control of Shoot Trauma Blight

Organization (s): Washington State University

PI (s): Santander, R.; Zhao, Y.; Sabe, A.; DuPont, T.

Total Funding Amount for All Years: $80,869

Length: 2 Years

Few tools are available to prevent shoot blight infections, especially after hail and wind damage (trauma blight). When such events are forecasted, streptomycin is used to protect young tender tissue from fire blight pathogen infection. Young susceptible trees of high-value cultivars may need repeated applications of copper to prevent wound-induced shoot blight. However, antibiotics and copper-based compounds rarely confer full protection, and their use has some drawbacks. This project aims to screen new compounds to prevent and control trauma blight caused by the fire blight pathogen. Products under consideration are biodegradable, pose low or no toxicity to humans, and have shown interesting bactericidal and/or plant defense-inducing properties in studies with other pathogens or plant models. The team will in vitro screen for antibacterial activity, dosage, and potential additive and/or synergistic effects in different products (e.g., soluble chitosan derivatives, rhamnolipids, lauric acid, caprylic acid) or mixtures with already used antimicrobials (essential oils, streptomycin, copper), elaborate a methodology to screen materials for shoot blight prevention and control, mimicking natural infection conditions after wind and hail damage, and finally evaluate in planta efficacy of products and/or product combinations in both greenhouse and field conditions.


Paige Beuhler (Administrative Officer):, 509 665 8271 ext. 2

Ines Hanrahan (Executive Director):; 509 669 0267

Washington State University