Efficacy of some biotic and abiotic treatments in controlling Alternariasolani the causal of tomato early blight disease in vitro and in vivo

Early blight of tomato caused by Alternariasolaniis one of the most common foliar diseases of tomato. Fivetested Trichoderma isolates were most effective in reducing growth of A. solani(As-3) than the tested Bacillus isolates. The highest reduction% was recorded with Trichodermaaureoviride-I(T-1) followed by Trichodermaaureoviride-II (T-2), Bacillussubtilis-I (B-24) and Bacillusamyloliquefaciens-II(B-19). Spraying plants with any of the tested antagonists before inoculation with A. solani under greenhouse conditions decreased the early blight disease severity (DS) by 15.1 to 45.3% compared with the infected control treatment with the pathogen only which recorded 93.4% of DS%. Bacillus amyloliquefaciens-II (B-19),T. virens (T-11)and T. harzianum-II (T-13) were the most effective for controlling early blight disease at 21-day post inoculation. All plant oils reduced the growth of A. solani isolate (As-3) with superiority of the high concentrations. The highest decreased % in growth of A. solani occurred with the 6.0% concentration. Among the five plant oils, cinnamon was the most effective followed by cloves then marjoram, while garlic was the least effective. Moreover, all oils at 3% concentration were moderately effective in controlling the disease. Clove and marjoram oil were the most effective in decreasing the infection at 21-day post inoculation with the pathogen while, garlic oil was the least effective. All tested chemical inducers reduced the growth of A. solani(As-3) on PDA plates. The high concentration 400 mM of sodium bicarbonate and potassium hydrogen carbonate was the most effective. Salicylic acid at 3 and 5mM was more effective in reducing the growth of isolate As-3 compared with the same concentrations of ascorbic acid. Spraying plants with the tested chemical inducers against early blight disease caused by A. solani(As-3) was moderately effective in controlling the infection. All tested chemical inducers controlled the early blight infection where the recorded DS% was ranged between 30.1 to 45.4% at 21day post inoculation with A. solani(As-3). Spraying tomato plants with salicylic acid was the most effective treatment in controlling A. solani (As-3) infection compared with the other chemical inducers.