Compatibility between biopesticides used to control grey mould, powdery mildew and whitefly on tomato

Botrytis cinerea, Oidium neolycopersici and Bemisia tabaci are among the most important pests encountered on tomato in greenhouses. In order to limit their development, biological methods of control have been elaborated. To protect pruning wounds against B. cinerea at crop level, the fungus Microdochium dimerum has shown a high efficacy. The formulated plant extract from the giant knotweed Reynoutria sachalinensis (Milsana) has shown a high efficacy to control powdery mildew of tomato. The myco-insecticide based on Lecanicillium muscarium (Mycotal) appears to be a promising biological control agent against whiteflies. The use of these products in a context of integrated protection of tomato requires that their efficacy is not altered when applied together. The objective of the present study was then to evaluate the compatibility of M. dimerum and plant extract with L. muscarium and vice versa. Compatibility tests were conducted on potted plants in controlled conditions. Mycotal had no significant effect on the susceptibility of tomato to either B. cinerea or O.. neolycopersici, and neither M. dimerum nor Milsana had any effect on the susceptibility of tomato to infestation by B. tabaci. The efficacy of Mycotal was not altered by application of M. dimerum or Milsana, and the efficacy of M. dimerum and Milsana remained unaffected by application of Mycotal. These results suggest that these biological products could be used together to intervene in tomato greenhouses. (C) 2008 Elsevier Inc. All rights reserved.