Control of diseases and aflatoxin occurences with proper cultural and disease management practices in peanut growing

This survey was done on 7 farmer fields and an experimental area in Osmaniye district in 2010-2011. This study concerned the diseases affecting local peanuts and the role played by various fertilization metods on the occurence of these diseases, aflatoxin production and the yield of the crops. In all survey areas crown rot (Aspergillus niger), stem rot (Sclerotium rolfsii) and leaf spot disease (Cercosporidium personatum) were observed. The most disease occurence and severity between them ranged for the stem rot %14.7-36.0 and %7.0-19.0, respectively. Infected plants were found to have the following fungi: S. rolfsii (%17.0-30.0), Aspergillus spp. (%18.0-29.0), Rhizoctoniasolani (%7.8-28.0), Fusarium spp. (%7.0-20.0). Plants ready for harvest, during drying and pre-post storage were found to infested with the fungi: Aspergillus spp. (%11.7-39.0), Fusarium spp. (%13.0-35.0), Rhizoctonia solani (%2.0-18.0), Macrophomina phaseolina (%1.0-24.0), Penicillium sp. (%3.0-9.0) and Rhizopus stolonifer (%1.0-57.0). In the identification of Aspergillus and Fusariumspecies; A. niger, A. flavus, F. solani, F. oxysporum, F. sambicinum and F. semitectum were determined. Toxins analysis of 96 separate samples from various parts of the experimental area, revelated no presence of aflatoxin, but 42 samples taken from survey fields and 23 samples from the storage places had less than 10 ppb aflatoxin, while 5 storage samples had afltoxin levels in excess of 10 ppb. Plant samples taken from the experimental and survey areas in flowering, post flowering and harvest periods, all had N levels near the minumum critical level. K levels of them were generally insufficient while P, Ca, Mg, S, Zn, Fe, Cu and Mn levels were within the accepted range. NC 7 type seeds produced 250.0-348.5 kg/da and Halis Bey seeds produced 485.0-525.0 kg/da. Test results with the experimental and survey areas soils and plants displayed insufficent potassium and minimal levels of nitrogen from a variety of causes, providing ideal conditions for the development of fungal diseases. The occurance of fungal diseases are also affected by cultural factors such as deep-plowing of soil, weed control, filling of soil onto plant crown, rotations, irrigations. The presence of aflatoxin was found to be more prevalent in storage period than drying and post harvest periods. Proper fertilization to provide sufficient nutrient concentrations, would result in healtier plants with a greater yield. Keywords: Peanut, plant disease, aflatoxin, nutrition deficiency