The efficacy of fungicides and biocontrol agents for control of <i>Glomerella cingulata</i> on Satsuma mandarins

Abstract

Six products were tested for efficacy for control of anthracnose caused by Glomerella cingulata on Satsuma mandarins There were three conventional fungicides (folpet copper hydroxide and mancozeb) and three new biological control agents (Botryzen Serenade and an experimental product HR42) Botryzen is a saprophytic fungus that competitively colonises plant material also invaded by pathogenic fungi Serenade is a saprophytic bacterium (Bacillus subtilis) that produces a diffusable substance that inhibits fungal pathogens and HR42 is a saprophytic bacterium with a similar mode of action to Serenade Application of Serenade HR42 and mancozeb significantly (Plt;0005) reduced symptoms (speckles) ascribed to G cingulata Isolations of Bacillus subtilis from leaf discs of Serenadetreated trees showed that leaves were successfully colonised by this bacterium up to at least a week after application Blotches that could not be removed appeared on fruit treated with Botryzen and copper hydroxide For Botryzen this may have been due to interaction with a surfactant