Integrated Botrytis cinerea Management in Southeastern Spanish Greenhouses

A strategy for integrated biological and chemical control of Botrytis cinerea in unheated tomato greenhouses in southeastern Spain was tested. The biocontrol agent used was a commercial preparation developed from an isolate of Trichoderma harzianum T39 (Trichodex ). Decisions concerning whether to spray the biocontrol agent or a fungicide were made based on a future weather disease warning system called BOTMAN implemented as follows: no spraying when slow or no disease progress was expected; use of a chemical fungicide when an outbreak of epidemics was expected; in all other cases, application of Trichoderma harzianum T39 was recommended. A 4-day weather forecast provided by the Eastern Andalusian Weather Forecast Service was used for predictions. The integrated strategy was compared with weekly applications of fungicides in two experiments conducted over 1998–99 and 1999–2000. Reduction of disease incidence was obtained only with the fungicide-only treatment in the 1998–99 experiment (55%, P<0.05). Application of BOTMAN gave high disease risk only in 2 dates or times in that experiment, so fungicides were only applied twice. For the remaining 12 dates or times, Trichodex was sprayed. In the second experiment, application of BOTMAN gave moderate risk all the weeks and Trichodex was applied nine times. In this experiment, disease level did not differ significantly (P<0.05) from untreated plot. The reasons for failure of BOTMAN in Spanish conditions were discussed