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Control of Botrytis In Greenhouse Grown Tomatoes 2002 N. B. Shamiyeh, A. B. Smith, And C. W. Meister Interpretive Summary All plots treated with a fungicide had a lower disease rating for Botrytis than those in the untreated plots. Plots treated with BAS-510 had a lower Botrytis Disease rating than in plots treated with the other chemicals. Introduction Early Blight and Botrytis has continued to be an annual problem in tomato production both in field and Greenhouse in Tennessee. Tomatoes are widely grown in Tennessee and diseases which thrives under the extremely humid weather conditions of this state, present a major concern for growers. Therefore, six fungicide treatments were evaluated for control of Botrytis on greenhouse grown tomatoes at the University of Tennessee Plateau Experiment Station in Crossville in 2002. Tests have been conducted for several years to evaluate different disease management strategies which include; rate adjustments, chemical combinations and alternate use of certain chemicals. The major commercial control strategies for diseases control have been a preventative spray program with fungicide applications made on a seven day schedule depending on weather conditions. Botrytis disease development is dependent upon a very strict set of weather conditions. Cool, wet, cloudy conditions favor Late Blight development. Materials and Methods Six foliar applied fungicides were evaluated for control of Botrytis in the greenhouse on tomato at The University of Tennessee Plateau Experiment Station, Crossville. ‘Celebrity’ tomato plants were transplanted in 2 gallon pots in the greenhouse on 16 Aug. Standard weed and insect control practices were implemented during the growing season. Plots consisted of 4 plants /treatment and spaced 3 feet apart replicated 4 times in a Complete Random Design. Plot size was 12 X 2 feet and blocks were 6 feet apart. Infected Geranium plants with Botrytis were placed in the greenhouse adjacent to the healthy tomato plants on 8 Aug. Tomato plants were inoculated with a suspension of Botrytis spores using a quart spray bottle on 22 Aug. Fungicide applications were made on 29 Aug, 5 , 12, and 19 Sept. Applications were made using a 2.5 gal CO2 backpack sprayer calibrated to deliver 60 gal/A at 40 psi. Weekly disease ratings ranged from 0 (no disease incidence) to 10 (100% leaf necrotic and defoliated ). Due to the lateness of the infection, yields were not taken. All data were subjected to ANOVA. Results and Discussion All plots treated with fungicide had a lower disease severity than the untreated check plots. By the 3rd application, plots treated with Scala and BAS-510 had lower disease ratings than any other treatment. After the 4th application, there were no significant differences in disease control among treatments. The Bio-fungicides are promising in providing effective control as well as safety. Table 1. Botrytis Disease Ratings of Celebrity Tomato Receiving Various Bio- Fungicides at the University of Tennessee Plateau Experiment Station, Crossville, 2002.
1 Botrytis Disease Rating: 0= No lesions or Leaf Necrosis present; 10 = 100% of leaves have necrosis. | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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