Diagnosis and Management of a New Disease of Cucurbits in Oregon

Winter squash is grown in the Willamette Valley of Oregon for fresh market sales and as a processing crop for pie filling and confectionary seed. However, a soilborne disease is reducing yield and quality of both fresh market and processing squash. The overarching goal of this project is to increase the economically viable production of winter squash and confectionary seed. This project will work towards that goal by diagnosing squash wilt and root and crown rot, identifying resistant/tolerant varieties, and evaluating the efficacy of crop rotation and available pesticides.

This project will engage project and other farmers throughout the course of the project. Field trials will be conducted on participating farm fields. Field tours will be conducted each fall. Project findings will be presented at the N. Willamette Hort Society Vegetable and Organic Days, the Oregon Processed Vegetable Annual Meeting, and the OSU Small Farms Conference. Farmers and buyers will interact with whole and cut squash at interactive conference booths each winter.

Objective 1) Engage project farmers in project development, delivery, evaluation, and outreach

Year 1. Discuss project plans with project farmers.

Years 1-2: Project farmers host field trials and participate in outreach events (presentations, conference booths)

Year 2: Farmers and collaborators discuss and evaluate project for final report (February 2017)

Results: Farmers are engaged in project development, delivery, evaluation, and outreach.

Objective 2) Identify causal agents of squash wilt and root and crown rot

Years 1 and 2: Isolate fungi from diseased plants. Evaluate pathogenicity of isolates on Golden Delicious in greenhouse and field trials. 

Results: Causal agents of squash wilt and root/crown rot are identified.

Objective 3: Identify squash cultivars with resistance or tolerance to squash root and crown rot/wilt, as well as good yield and long shelf life

Years 1-2?. Variety trials will be conducted on farms with known history of wilt and crown/root rot to Identify tolerant and resistant varieties. Varieities will be evaluated for disease susceptibility, yield, and storability.

Results: Resistant and tolerant varieties are identified and their potential yield and storability described.

Objective 4: Evaluate the efficacy of crop rotation

Years 1-2: Squash crops planted to fields of varied squash cropping histories will be scouted for root and crown rot and vascular discoloration and those data related to field cropping history.

Results: Efficacy of rotation and required rotation length are described.

Objective 5: Evaluate the efficacy of available pesticides and their interactions with herbicides

Years 1-2: Fungicide and herbicide field trials will be conducted in Golden Delicious fields of known soilborne disease history.

Results: Efficacy of pesticides and any interactions with herbicides are described.