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Efficacy of organic treatments for managing tomato foliar and soilborne diseases in WV

Rahman Mahfuz: West Virginia University

<div>Early blight, Septoria leaf spot and soilborne wilt diseases of tomato cause significant yield losses on in WV every year. Many small growers in the state do not want to use harsh chemicals. This study determined the efficacy of early blight (EB) resistant varieties, Mountain Fresh Plus F1 (MF+) and Juliet F1 together with the treatments of ‘Brandywine’ by 1) Kocide-started at pre-bloom on a seven-day schedule; 2) Regalia + Kocide alternated by week starting at pre-bloom; 3) Kocide at first symptom appearance (seven-day interval afterwards); 4) Serenade and 5) Actinovate on a seven-day schedule starting at pre-bloom; and 6) Non-treated control at the WVU certified organic farm in a RCB design with four replications. All treatments except Actinovate and Kocide (on symptom appearance) significantly (P≤ 0.04) reduced EB severity compared to the non-treated control. Another study was conducted with heirloom tomato ‘Mortgage Lifter’ to investigate the efficacy of bio-fumigants, biological antagonists, and resistant rootstock in managing wilt disease. Thirty-five DAP, grafted (on resistant rootstock “Maxifort”) tomato plants showed significantly higher plant vigor compared with non-treated check. All treatments had significantly lower symptomatic leaves than that of non-treated check. Cumulative harvests for six weeks showed that yield from all treatments were significantly (P<0.001) higher compared with non-treated check. Grafted plants produced 20 lb tomatoes/plant compared with only 11 lbs by non-treated check. Results suggest that organically acceptable methods can reduce both foliar and soilborne diseases if applied on time, and provide significant yield advantage to heirloom tomatoes.</div>