Effect of biotherapic of Alternaria solani on the early blight of tomato-plant and the in vitro development of the fungus

Abstract

Background: homeopathy is a means permitted in organic agriculture to control disease and plagues; biotherapics are a practical means for farmers to intervene on the health of plants in agro-ecological systems of production. Tomato-plants can be affected by several diseases, one of the most significant ones in Brazil is early blight, caused by fungus Alternaria solani, due to the damage it causes and its wide distribution in the country. Aims: to establish whether a biotherapic of A. solani may interfere on the in vitro development of the fungus and whether it affects the severity of early blight on tomato-plants in greenhouse. Methods: the effect of the biotherapic on the fungus was evaluated through the percentage of germinated spores under microscope and the growth of colonies in a culture medium. Treatments used were: biotherapic 26cH, 27cH, 28cH, 29cH and 30cH; sterilized distilled water; and diluted and agitated hydroalcoholic solution. The effect of the biotherapic on the development of disease was evaluated in 4 experiments in greenhouse. Plants were kept in vases and subjected to artificial inoculation of the fungus after the application of treatments. Evaluation of disease was carried out through diagrammatic scale. Results: no treatment affected the germination of spores or the development of fungus colonies in the culture medium. In the first test, treatment 26cH differed from water in Tukey’s test at 5% but did not differed from diluted and agitated hydroalcoholic solution. In the second test, treatments 27cH and 28cH showed significant difference from both water and hydroalcoholic solution with an average control of disease of 57% and 62% respectively. The other 2 tests did nor exhibit any significant effect. Conclusions: there was no direct effect of the biotherapic on the fungus, but there was an effect on the severity of the disease. Factors affecting the efficiency of the biotherapic must be better understood before it can be recommended to farmers for the management of early blight in tomato-plants.

Research Advances in Preparation, Stability, Application, and Possible Risks of Nanoselenium: Focus on Food and Food-Related Fields

“…Early blight is a disease caused by Alternaria solani, which seriously affects tomatoes and other solanaceous plants. 98 It can cause defoliation of plants in leaves and necrosis of stems and fruits in serious cases, leading to plant death. 99 Quiterio-Gutieŕrez et al 100 applied nanoselenium and nanocopper (10 mg/L SeNPs + 50 mg/L CuNPs) to treat tomato early blight, and the results showed that the severity of the tomato infected with bacteria was reduced by 6%.…”

“…In addition, SeNPs can maintain the composition and integrity of the thylakoid membrane. Early blight is a disease caused by Alternaria solani, which seriously affects tomatoes and other solanaceous plants . It can cause defoliation of plants in leaves and necrosis of stems and fruits in serious cases, leading to plant death .…”

Efficacy of certain chemical Fungicides and Biofungicides on early blight disease in tomato under field conditions

“…Alternaria leaf blight is an important disease of tropical and sub-tropical areas (Yashwant et al, 2017). Alternaria solani usually infect solanaceous crops including potato, tomato, eggplant and pepper (Carneiro et al, 2010).This fungus causes infection on leaves, stem, petiole, twig and fruits as well as leads to the defoliation, drying of twigs and premature fruit drop which ultimately reduce the yield 30 to 65 % in various states (Basu, 1974;Datar and Mayee, 1981;Kamble et al, 2009;Saha and Das, 2013). The disease, if favored by high temperature and humidity (crowded plantation, high rainfall and extended period of leaf wetness from dew) and plants are more susceptible to the blight infection during fruiting period (Momel and Pemezny, 2006).…”