Biocontrol of grey mould by Ulocladium atrum applied at different flower and fruit stages of strawberry
Pedro Boff, Jürgen Köhl, Matthijs Gerlagh and Joop de Kraker
BioControl 47 (2): 193-206. 2002.
2002
บทคัดย่อ
Biocontrol of grey mould by Ulocladium atrum applied at different flower and fruit stages of strawberryGrey mould is an important disease ofstrawberries resulting from flower and fruitinfection by Botrytis cinerea Pers. Thesaprophytic fungus Ulocladium atrumPreuss is a promising biological controlagent for control of B. cinerea instrawberry and other crops. The objective ofthis research was to determine the efficacy of U. atrum to control grey mould by asingle application of a spore suspension (2 ×106 conidia/ml) at different flowerand fruit development stages. Four experimentswere carried out in 1999, two under natural andtwo under enhanced inoculum levels of B.cinerea. In each experiment, flowers and youngfruits in six distinct stages of developmentwere sprayed with either water or U.atrum suspension. U. atrum suppressedB. cinerea sporulation on petals by 15 to54%. one to four days after spraying, U.atrum was present on less than 30% of stamensand did not affect the incidence of B.cinerea on these flower parts. The efficacy ofthe U. atrumsprays in controlling greymould was low to moderate, and resulted onaverage in a reduction of 21% in diseaseincidence on ripe fruits. Low control efficacywas probably due to poor coverage with orcolonisation of stamens by U. atrumspores, and a relatively low level ofsuppression of the colonisation of flower partsby B. cinerea. Significant reductions ofgrey mould in comparison to the control (p£ 0.10; on average 41% reduction) werefound most frequently when the antagonist wasintroduced at late flowering or early fruitstages. Therefore, these are the most suitablestages to apply U. atrum. Further studiesare needed to improve the spray coverage andpersistence of U. atrum inoculum.