Role of Chemicals for Plant Resistance, Trichoderma Bioagents and Cow Whey Milk in Combination on Management of Tomato Powdery Mildew

The tested inducer resistance chemicals (IRCs) Bion, chitosan, and salicylic acid, Trichoderma strains ,i.e. T. album, T. hamatum, T.koningii ,T. harzianum and T.viride. and cow milk ,i.e. full cream, skim and whey resulted in significant reduction to the germinated conidia of Leveillula taurica ( anamorph Oidiopsis taurica,) with control treatment. This reduction was gradually increased by increasing the tested concentration.

In field experiments during 2016 and 2017 growing seasons at Dakahlia governorat, Egypt, spraying of tomato plants with the tested IRC Bion , the bioagents T.koningii and T.harzianum and cow whey milk , each alone or in different combinations, resulted in significant reduction to the severity of the disease with significant increase to the produced fruit yield . Furthermore, spraying of any of these compounds alone was of less effect in this regard compared with spraying of their combinations. However, the fungicide Sumi-8 was the superior treatment in this regard, being 3.2 % disease severity and fruit yield 185 kg. / plot (42 m2) followed by the mixture of the three treatments, being 4.0 % disease severity and fruit yield 181 kg. / plot (42 m2).

There were considerable increase in chlorophyll a, chlorophyll b and carotenoids as well as free and total ascorbic acid (vitamin-C) due to the tested treatments, i.e. both bioagents, BTH and cow whey milk in tomato plants under the natural infection by powdery mildew in comparison with those of untreated plants. BTH was the best treatment for minimizing the reduction in photosynthesis pigments as well as free and total ascorbic acid in plants infected by the disease compared with un-infected plants by the causal fungus (control). 

Keywords: Tomato, ascorbic acid, cow milk, inducer resistance chemicals, photosynthesis pigments, powdery mildew and Sumi-8, Trichoderma spp.