Project Overview
Commodities
- Vegetables: cucurbits
Practices
- Education and Training: on-farm/ranch research
- Pest Management: integrated pest management, prevention
Proposal abstract:
Pseudoperonospora cubensis is an oomycete pathogen that causes cucurbit downy mildew (CDM) on a wide range of cucurbitaceous hosts. CDM results in significant crop losses in the US annually, and it is a major disease limiting cucurbit production. The pathogen has two genetic clades that have differences in host preference and fungicide sensitivity. This pathogen is dispersed via air currents and it is mainly managed with weekly fungicide applications since complete host resistance is not commercially available. Contact fungicides are applied weekly while CDM site-specific fungicide applications are only initiated once the disease is detected in a neighboring state due to their higher cost. A challenge in CDM management is cost-effective fungicide use and prevention of fungicide resistance for site-specific fungicides. To reduce fungicide application costs and improve outcomes, we propose a CDM monitoring system that relies on mobile spore trapping combined with molecular tests for pathogen clade detection and fungicide resistance monitoring. Our system will quickly sample large fields to detect the pathogen prior to disease onset, which will reduce the number of applications for site-specific fungicides. Our qPCR molecular tests will inform: 1) which host to spray based on clade detection and host preference, 2) which fungicides are not effective due to detection of fungicide resistance mutations. Our CDM biosurveillance system will empower growers with real-time weekly information of airborne inoculum levels to best utilize site-specific fungicides for CDM management while preventing fungicide resistance.
Project objectives from proposal:
1. Determine if a vacuum and a roto-rod spore trap can detect pathogen spores before any disease can be observed on crop leaves.
-Expected outcome #1: Results will help assess which trap type is best at capturing P. cubensis sporangia.
2. Determine which vehicle type (drone, rover, stationary) is most effective for pathogen spore sampling with vacuum and roto-rod spore traps.
-Expected outcome #2: Results will serve to address which vehicle-trap combination is better to use for a future biosurveillance system in large commercial fields.
3. Determine the occurrence of clade, Oxysterol binding protein inhibition (OSBPI), Carboxylic Acid Amide (CAA) and Quinone outside Inhibitor (QoI) fungicide resistance in spore trap samples to establish fungicide resistance patterns in the populations of the pathogen (P. cubensis).
-Expected Outcome #3: Results will serve to establish which products are not effective for CDM management.