Directed Fungicide Application for White Mold Control on Peanut.

White mold, caused by Sclerotium rolfsii Sacc., is a major disease affecting peanut production in the southeastern US. Effective control entails delivery of fungicides at the site of infection located at the crown of plants at the stem-soil interface. Directed fungicide application to control white mold on peanut has not been investigated, but may result in more effective control at lower spray volumes. The objective of this study was to evaluate a directed spray program for white mold control during peanut production. A 2 x 2 x 2 factorial experiment in a randomized complete block design with four replications was implemented in Jay, FL in 2016 and 2017. Factors evaluated were spray method (broadcast and directed), nozzle type – spray volume (hollow cone – 47 l ha^-1 and wide angle flat fan – 189 l ha^-1), and fungicide (Convoy® and Priaxor®). A non-treated control was also included. Plots (13.7 m²) were inoculated at peanut cracking to ensure high disease pressure. Fungicide treatments were imposed 60 and 90 days after planting. White mold scoring occurred every two weeks following fungicide application. In 2016, directed application of Priaxor® at 189 l ha^-1 resulted in lower white mold incidence compared to directed and banded applications of Convoy® at both spray volumes. However, these treatment differences were not observed in 2017. Directed application of both fungicides at 47 l ha^-1 produced similar peanut yields to plots where fungicides were broadcasted at 189 l ha^-1. These preliminary results provide some evidence that directed application of fungicides can reduce white mold incidence on peanut, and that peanut yield is not reduced by directed spraying at lower volumes.