ISHS Acta Horticulturae 808: II International Symposium on Tomato Diseases
EVALUATION OF TREATMENTS FOR MANAGING FOLIAR DISEASES IN ORGANICALLY-PRODUCED TOMATO |
| Author: | M.T. McGrath |
| Keywords: | compost tea, organic, powdery mildew, bacterial speck, Septoria leaf spot |
| Abstract:
Four experiments were conducted under field conditions in 2003-2006 to evaluate treatments applied to foliage for diseases in tomato grown for fresh-market consumption. Diseases were powdery mildew, Septoria leaf spot, bacterial speck, and leaf mold. Incidence and severity of these naturally-occurring diseases were not detectably affected by preventively applying a bacterial-dominant compost tea and/or a biofungicide (Bacillus subtilis formulated as Sonata) starting about 30 days after transplanting or by switching after disease detection from compost tea to a copper fungicide (Champion) and a mineral oil (JMS Stylet-oil). Compost tea was applied once to twice a week. Tomatoes were transplanted no-till into a hairy vetch-rye mulch. Plants were staked and trellised to obtain an up-right growth habit. All treatments were made with a back-pack sprayer with hand-held boom. Hairy vetch, which is known to activate defense genes in tomato, did not affect disease occurrence when used as a mulch in this production system based on a comparison with tomatoes grown in bare-ground in 2005 when leaf mold predominated. A citrus acid product that reportedly promotes plant health, AgriLife, suppressed leaf mold in 2005 and powdery mildew in 2006. Champion also controlled powdery mildew. Neither product was effective for Septoria leaf spot. None of the treatments increased yield of ripe fruit. | |
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