MANAGING BOTRYTIS-CINEREA ON TOMATOES IN GREENHOUSES IN THE MEDITERRANEAN

Nine experiments were carried out from 1989 to 1992 in Israel and in northern Italy in greenhouse-produced tomatoes infected with Botrytis cinera Pers., Fr. In Israel B. cinerea affected leaves, stems and fruits (both rot and ghost spot symptoms were apparent). In Italy, the only symptom of the disease was fruit rot. Several fungicides, fungicide mixtures and spraying programmes were applied. Some trials also included 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 procymidone) applied alone suppressed the disease by 40-88%, as effectively as its mixture with thiram, dichlofluanid or tebuconazole. Similar disease suppression was achieved by mixtures of tebuconazole + dichlofluanid and carbendazim + diethofencarb. Trichoderma harzianum T39 alone reduced disease by 31-82% but in more than half of the cases the reduction was non-significant. Disease control achieved by the biocontrol preparations did not differ significantly (p = 0.05) from that achieved by the chemical fungicides. Adequate control was achieved when the biocontrol and the chemical products were applied alternately although the quantity of chemical sprays was reduced by one half. The consistency among treatments in the various trials with respect to percent disease control was greater in the T. harzianum-fungicide alternation treatments, than that in the T. harzianum or the fungicide treatments applied alone.