MUTUALISM BETWEEN A PHYTOPATHOGENIC FUNGUS (BOTRYTIS-CINEREA) AND A VINEYARD PEST (LOBESIA-BOTRANA) - POSITIVE EFFECTS ON INSECT DEVELOPMENT AND OVIPOSITION BEHAVIOR

In vineyards, larvae of the grape berry moth (Lobesia botrana) favour the development of the grey mould fungus Botrytis cinerea. To study th e possibility of a mutualistic relationship between these organisms, w e investigated the effects of the fungus on the development and ovipos ition behaviour of the insect. Larvae were reared on whole plants infe cted or uninfected with the fungus, or on an artificial diet containin g either infected grape berries or the mycelium. The presence of the f ungus consistently led to a reduction in the duration of insect develo pment (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 betwee n the two organisms which are both damaging to vineyards. ((C) Academi e des sciences / Elsevier, Paris).