NC County Extension Agents Practice Cucurbit Disease Identification Techniques

— Written By Mary Lorscheider and last updated by

As part of NC State University Department of Plant Pathology and Entomology’s annual agent training each July, the Vegetable Pathology Lab at NC State University conducted disease identification workshops for county extension agents in both the lab and field. The workshops focused on the identification of cucurbit and other crop pathogens. When disease strikes, time is of the essence for disease identification and the implementation of control measures. County agents provide a grower’s initial contact with Cooperative Extension and connect cucurbit producers with the Vegetable Pathology Extension specialist and the Plant Disease and Insect Clinic.

The goal of the Vegetable Pathology Lab at NC State University is to deliver science-based management strategies to North Carolina growers. County agents are an integral connection between the growers and University Vegetable Pathology specialists who have become partners in research, discovery, and innovation that are important for the state’s agricultural and economic health.

During the July 2019 Annual agent training, the NC State University Department of Entomology and Plant Pathology’s Vegetable Pathology Lab shared disease diagnostic techniques for cucurbit pathogens including Gummy Stem blight, Downy Mildew, and Phytophthora with county Extension agents from across NC. On the first day, agents practiced their diagnostic skills at the Central Crops Research Station in Clayton, NC on cucurbit crops inoculated with pathogens. County Extension personnel networked with specialists, members of the Quesada Lab and fellow agents. On the second day of training, the group visited the Plant Disease and Insect Clinic and then practiced disease diagnostic techniques in a lab equipped with microscopes and the basic instruments recommended for disease diagnostics.

agents in watermelon field

Agents walk the plots at field sites and make notes on signs and symptoms of disease. Vegetable pathologists and entomologists are available for any questions that the Agents might have.

Agents touring watermelon field

Watermelon plants exhibiting symptoms of Cucurbit Downy Mildew and Gummy Stem blight were on site for County Extension Agents to practice their diagnostic skills on.

disease symptoms on leaf

Examples of disease symptoms were present on the leaves of several cucurbit species.

Lab members in the field

Lab leader, Dr. Lina Quesada along with research assistants and plant pathology students Mike Adams, Hunter Collins, Andres Salcedo, Savithri Purayannur, Jeff Standish, Kim D’Arcangelo, Madison Stahr, Camilo Parada, and Sammi Wong presented information about vegetable diseases, their life cycles, and disease management strategies.

samples on tables

Agents visited the NC State Plant Disease and Insect Clinic where grower’s samples are sent after initial diagnosis in the field. The diagnostic lab saves records of disease diagnoses’ in a database.

plant disease clinic lab

The Plant Disease and Insect Clinic uses advanced techniques to confirm initial disease diagnosis.

close up view of slide mount preperation

County agents practice slide mount techniques.

diagnostic tools

Basic supplies for plant disease diagnostics include hand lenses, microscopes, scalpel, water bottles, tape, knives, dissecting needles, scissors, glass slides, coverslips, plastic bags, glass beakers, and hand lenses.

test strip next to a diseased watermelon

A quick field test for Phytophthora is available for agents to make an initial diagnosis in the field.

using a smartphone to take a picture through the microscope

Extension Agents learned techniques for confirmation of their initial diagnosis in the county. Agents can photograph images of disease organisms through their microscope with a smartphone and then send the image to specialists.