Archives for May 2013

Disease severity values (DSVs) for early blight, septoria leaf spot, and tomato anthracnose development are determined daily based on leaf wetness (due to rainfall, dew) and air temperature.

On a daily basis DSV values can range from 0 to 4 where 0 = no chance for disease development to 4 = high chance for disease development.
DSVs are accumulated during the production season.

Fungicide applications are based on an individually determined DSV threshold. The first fungicide application for the control of these three diseases is not warranted until 35 DSVs have accumulated from your transplanting date. After that, growers can base fungicide applications on different DSV thresholds.

Filed Under: Disease Forecasting

May 23, 2013 A.Wyenandt, W.Kline, and J.Ingerson-Mahar

Potato Disease Forecasting Report 5-24-13

Potato Disease Forecasting Report 5-24-13 – Click to Download

Welcome to the new potato report for 2013! As always, we will be tracking DSVs for Late blight development and calculating P-days for initiating the first early blight fungicide application. Remember the threshold for P-days is 300! Once 300 P-days is reached for your location early blight fungicide applications should be initiated.

Filed Under: Disease Forecasting

May 23, 2013 Peter Oudemans

Management of Phytophthora Root and Runner Rot in Cranberry

by Peter V. Oudemans, Extension Specialist
and Anne DeMarsay, Post Doctoral Researcher

Vines affected by Phytophthora Root and Runner Rot will decline from the root system up. Accurate diagnosis is important and may require identification by a trained plant pathologist.
Key factors for effective management include:

Identification of the pathogen

Soil drainage rates

Soil drainage uniformity

Irrigation uniformity

Irrigation volume

Timing of fungicide applications

Download the full article

Filed Under: Cranberry

May 23, 2013 Andy Wyenandt

Vegetable Briefs 5-24-13

Cucurbit downy mildew was reported on cucumber as far north as Southern Georgia this past week.
Crown rot and leather rot (fruit rot) caused by Phytophthora spp. were found on strawberry this past week.
Bacterial problems in strawberry, parsley, and lettuce were reported this past week. With the rain and windy weather predicted over the next few days conditions will be ideal for the bacterial diseases.
No late blight has been reported in the region to date.

Filed Under: Vegetable Crops