ผลของไนโตรเจนและแมงกานีสร่วมกับ Bacillus subtilis สายพันธุ์ SM1 ต่อ Rigidoporus microporus สายพันธุ์ NK6 สาเหตุโรครากขาว ของยางพารา (Hevea brasiliensis)

Abstract

The southern soils have high development with easy loss of nutrients, especially nitrogen. Most rubber planting areas are acidic soils. Consequently, there is a high solubility of manganese to dissolve beyond the standard. Currently, areas of rubber (Hevea brasiliensis) plantation have increased continuously and neglected proper fertilizers in accordance with the recommendations, cause white root disease of para rubber (Rigidoporus microporus). Bacillus subtilis has been reported as antagonistic to a variety of plant pathogens. The objective of this work was to study the effect of nitrogen and manganese with Bacillus subtilis SM1 strain for inhibiting Rigidoporus microporus NK6 strain and fertilization application with B. subtilis strain SM1 for control white root disease of para rubber (Rigidoporus microporus NK6 strain). The study consisted of two parts. Part 1: Test in the laboratory with 3 factors, nitrogen [(NH4)2SO4], manganese (MnSO4) and a combination of nitrogen and manganese at 5 levels. Part 2: The study investigated the effects of fertilizer with soil test and those which were fertilized with 20-8-20 (control, B. subtilis, R. microporus and B. subtilis + R. microporus). The results of in the combination environment of nitrogen or manganese or nitrogen with manganese, still B. subtilis SM1 strain was able to grow indifferently at all concentration. The increasing of nitrogen levels or nitrogen combined with manganese results a decrease in growth of R. microporus NK6 strain mycelium. Manganese at a concentration more than 0.056 molar decreased the growth of mycelium. With nitrogen or manganese or nitrogen-manganese combination in various concentrations was also inhibited the growth of R. microporus NK6 strain mycelium by more than 80 percent, such as rough mycelium, uneven fiber sizes, distorted growth and distend end of mycelium. Moreover, fertilizer with soil test and those which were fertilized with 20-8-20 and a combination of B. subtilis SM1 strain reduced the incidence of white root rot fungal disease 42-100 percent. Fertilizer application based on soil testing with B. subtilis SM1 strain increased shoot system and stem diameter for rubber. Nitrogen and manganese with B. subtilis SM1 strain was also inhibited the growth of R. microporus NK6 strain mycelium. Fertilizer application based on soil testing with B. subtilis SM1 strain reduced the incidence of white root rot fungal disease by more than 97 percent. There should be further develop to be in formulation.