N. B. Shamiyeh , A. B. Smith, and C. W. Meister

All treated plots had significantly lower disease ratings and less % Culls than the untreated check. Powdery Mildew was the predominant diseases.

Squash production in Tennessee is threatened by a wide variety of fungal pathogens that attack foliage and fruit. One common problem with, especially with late planting, is powdery mildew, most commonly caused by Sphaerotheca fuliginea. This trial was designed to evaluate the efficacy of certain bio-pesticides for control of powdery mildew on squash. These chemicals are very safe and goes on fast track for registration.

Four foliar fungicide treatments were compared to an untreated check for control of powdery mildew. Fertilization consisted of 400 lb of 15-15-15 applied broadcast and disc incorporated on 3 May. Transplants of ‘Dixie’ were transplanted on 10 May. Plot size was a single row, 10ft long and 5ft wide containing 5 hills of squash. Treatments were replicated 4 times in a randomized complete block design. Weed and insect control were maintained in the conventional manner during the growing season. Fungicide applications were made on 11, 17, 27 July and 1 Aug using a Solo backpack mist blower at 136gal of solution per acre. Disease ratings ( 0-10 with 0 being no disease symptoms showing and 10 being 100% of the plants showing symptoms) were made on 3, 11, 17, 25 Jul and 1 Aug. Plots were hand harvested four times and yield were added together for total of the four pickings. All data were analyzed by ANOVA.

All Plots treated with fungicides had lower disease ratings for powdery mildew than the untreated check plots. Plots treated with Seranade had a higher disease rating for Powder Mildew than the other fungicide treatments but lower than the untreated plots, and produced more % squash culls than the untreated check plots ( Table 1 ).

Table 1. Powdery mildew ratings of squash receiving various fungicide treatments at The University of Tennessee Plateau Experiment Station, Crossville, 2001.

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This research represents one season's data and does not constitute recommendations.  After sufficient data is collected over the appropriate number of seasons, final recommendations will be made through research and extension publications.