MANAGING BOTRYTIS-CINEREA ON TOMATOES IN GREENHOUSES IN THE MEDITERRANEAN

Nine experiments were carried out from 1989 to 1992 in Israel and in n orthern Italy in greenhouse-produced tomatoes infected with Botrytis c inera Pers., Fr. In Israel B. cinerea affected leaves, stems and fruit s (both rot and ghost spot symptoms were apparent). In Italy, the only symptom of the disease was fruit rot. Several fungicides, fungicide m ixtures and spraying programmes were applied. Some trials also include d a biological preparation based on Trichoderma harzianum isolates T39 and TF. Although a dicarboximide-resistant population of the pathogen existed in all greenhouses, dicarboximide fungicides (iprodione or pr ocymidone) applied alone suppressed the disease by 40-88%, as effectiv ely as its mixture with thiram, dichlofluanid or tebuconazole. Similar disease suppression was achieved by mixtures of tebuconazole + dichlo fluanid and carbendazim + diethofencarb. Trichoderma harzianum T39 alo ne reduced disease by 31-82% but in more than half of the cases the re duction was non-significant. Disease control achieved by the biocontro l preparations did not differ significantly (p = 0.05) from that achie ved by the chemical fungicides. Adequate control was achieved when the biocontrol and the chemical products were applied alternately althoug h the quantity of chemical sprays was reduced by one half. The consist ency among treatments in the various trials with respect to percent di sease control was greater in the T. harzianum-fungicide alternation tr eatments, than that in the T. harzianum or the fungicide treatments ap plied alone.