Integrated Management for Botrytis Control in Rose.

Rose is one of the main exporting crops in Colombia. Botrytis is one of the most important diseases affecting quality of the rose and it is usually handled by the application of chemical fungicides. We have developed an integrated approach to manage the disease, which includes balanced soil and nutrient management, and the application of a microbial inoculant, to both soil and plant. The study was performed in a rose block of the variety Vendela, susceptible to Botrytis cinerea. The baseline for the block included a detailed mapping of the main soil chemical properties as well as the plant nutrient content. The historical incidence of Botrytis within the block was also mapped. A cluster analysis on plant nutrient content and soil properties was performed and related to disease presence. Three treatments were evaluated with three replications (beds): 1) Chemical control (actual management, by calendar), 2) integrated (alternating microbial inoculant, twice a week, every 15 days, and chemical, once every fifteen days), 3) biological (microbial inoculant once a week, every week). The microbial inoculant consisted on a bacterial consortium with different functions. The inoculant was applied at 2.5% (v/v) and its original concentration was 1 x 10(8) UFC/ml. The incidence and severity of the disease was evaluated weekly. Besides during the experiment, the biomass of the crop was estimated by using a NDVI obtained with the OptRx active sensor (AgLeader Technologies). Results indicated a strong association between the historical incidence of Botrytis with the clusters made from plant and soil nutrient content. Clusters with high nutrient levels tended to have botrytis incidence. Significant differences were observed among treatments. The application of microbial inoculant along with adjusted nutrient rates and organic matter application shows promise for the integrated control of botrytis in rose.