Mutualism between a phytopathogenic fungus (Botrytis cinerea) and a vineyard pest (Lobesia botrana). Positive effects on insect development and oviposition behaviour

In vineyards, larvae of the grape berry moth (Lobesia botrana) favour the development of the grey mould fungus Botrytis cinerea. To study the possibility of a mutualistic relationship between these organisms, we investigated the effects of the fungus on the development and oviposition behaviour of the insect. Larvae were reared on whole plants infected or uninfected with the fungus, or on an artificial diet containing either infected grape berries or the mycelium. The presence of the fungus consistently led to a reduction in the duration of insect development (4-6 d) and mortality (20-67 %). The fecundity increased from 12 to 76 %. Moreover, the fact that the females laid eggs preferentially on fungus-infected grape berries confirms the mutualistic association between these organisms. The fungus alone contributed to the positive effects. We showed the existence of a mutualistic relationship between the two organisms which are both damaging to vineyards. ((C) Academie des sciences / Elsevier, Paris).