Polyoxin D and Other Biopesticides Reduce Gummy Stem Blight But Not Anthracnose on Melon Seedlings

Abstract

Biopesticides may be useful to prevent fungal foliar diseases on cucurbit seedlings in greenhouses because of the short re-entry intervals, normally 4 h. Bacillus subtilis QST 713 (Serenade ASO), root extract of Reynoutria sachalinensis (Regalia), hydrogen dioxide (Oxidate), paraffinic oil (JMS Stylet Oil), polyoxin D (Oso), and 92% edible fish oil + 5% sesame oil (Organocide) were evaluated against gummy stem blight on muskmelon seedlings and anthracnose on watermelon seedlings. Polyoxin D applied alone, B. subtilis QST 713 followed by polyoxin D, and R. sachalinensis extract followed by B. subtilis QST 713 reduced the severity of gummy stem blight and were as effective as mancozeb. None of the biopesticides applied alone or sequentially were effective against anthracnose. Polyoxin D could be used to prevent outbreaks of gummy stem blight on watermelon and muskmelon seedlings grown for use as transplants. Accepted for publication 1 July 2016. Published 4 August 2016.