SAFE CONTROL OF SOIL BORNE PATHOGENS OF BELL PEPPER PLANTS UNDER PLASTIC-HOUSE CONDITIONS

The experiments were conducted at the farm of Al-Alamia located at Nubaria- Egypt, in plastic houses (6m x 45m) where solanaceous crops have been grown as monoculture, and aimed to evaluate the soil solarization in combination with benefit microorganisms for controlling the pepper soil borne pathogens and weeds under plastic-house condition. Supplementation of organic matter in plastic-houses resulted in noticeable increase in fungal, bacterial and nematode counts. However, the population densities of total fungi,Fusaria, total bacteria, spore former bacteria, actinomycetes and nematodes after 15 and 30 days in the solarized plastic-houses were drastically reduced as compared tonon solarized control soil. This reduction was gradually increased depended on the time of sampling (after 15 days of transparent polyethylene mulching or after 30 days). Soil solarization reduced sharply free nitrogen fixers, 30 days after treatment the elimination of the Azotobacter spp. and Azospirillum spp. from soil was recorded. However, the free nitrogen fixers were found to be recolonized after one month from transplanting the seedling pepper plants in non solarized and solarized soil, so artificial inoculation of pepper seedlings with strains of Azotobacter sp. and Azospirillum sp., were resulted great root colonization of plants than in non-solarized soil. Also, all annual weeds have been controlled with soil solarization which gave the best weed control treatment. On the other hand, solarization had pronounced effect on seedling establishment occurred in solarized plastic-houses. Increasing more than 30% in establishment of pepper seedling were recorded between the solarized and non-solarized plastic-houses which mulched with black sheets after three weeks of pepper transplanting.  The percentage of Phytophthora spp. isolated from the infected pepper seedlings were very high compared with other fungi, it was 49% of total isolated fungi after one week of transplanting. However, soil solarization increased pepper plant height and number of branches per plant as compared with non-solarized soil without black mulching or with black mulching. The pepper yield per plastic house up to 7 months increased with soil solarization by about 216 Kg, 18.3% over non solarized with black mulching, and 155 Kg, 12.4% over non solarized without mulching.