Peanut Disease Update

Recent warm, wet weather has been optimal for both plant growth and fungal disease development in peanut and other crops. Early planted peanut in southeastern Virginia is near the R3 (beginning pod) stage, so it is almost time to make the first fungicide application for leaf spot. The first spray can be delayed until two weeks after R3 on Bailey. Last effective spray dates for leaf spot can be found on the Virginia Peanut-Cotton Infonet website.

Sclerotinia blight risk in based on temperature, rainfall/humidity, and crop growth. Temperature and rainfall have been conducive for Sclerotinia blight, but Sclerotinia risk is considered low to moderate prior to canopy closure. However, rapid growth of the peanut crop in some fields has resulted in thick canopies that provide the moist micro-climate necessary for disease development. Thus, now is the time to start scouting for Sclerotinia blight in peanut fields, especially if vines are within six inches of touching. If the wet weather continues, Sclerotinia blight risk is expected to be high within the next couple of weeks.