INFLUENCE OF GROWING SWEET PEPPER IN COMPACTED RICE STRAW BALES COMPARED WITH NATURAL SOIL, ON INFECTION WITH PATHOGENIC FUNGI AND NEMATODES UNDER GREENHOUSE CONDITIONS

Rice straw bales could be used as a growing media for cultivation of vegetable crops instead of soil. The present study, which is considered the first in this respect in Egypt, aimed to evaluate the effect of using rice straw bales as a medium for cultivation of pepper on the disease infection by root pathogens. The cultivation of sweet pepper seedling cv.4408 F1 hybrid on rice straw bales was carried out in two locations: in El-Ismailia Gover-norate (Abo-Swear and El-Ferdan Districts), under plastic net greenhouse conditions during 7-10 May. 2007. In the first location, Abo-Swear, the disease incidence of root rot, wilt and root knot nematodes in sweet pepper plants grown in rice straw bales reached 1.1, 0.85 and 0.0% respectively. However, the corresponding figures for sweet pepper plants grown in natural soil under the same conditions were 14.8, 21.9 and 33.2%, respectively. The same trend was observed in the second location El-Ferdan district. Determination of pathogenic nematodes in rice straw bales and natural soil re-vealed the presence of 80 juvenile (J2) of Meloido-gyne spp. and 120 juvenile (J2) of Tylenchorhyn-chus sp. per 250 g natural soil. However, the path-ogenic nematodes were absent in rice straw bales. Isolation trials from naturally root –rotted and wilted pepper plants grown in natural soil and compacted rice straw bales under plastic net house conditions indicated that both Fusarium oxysporum Schlecht and Rhizoctonia solani kuhn were the most fre-quent isolated fungi . Other associated fungi be-longing to the genera Pythium, Sclerotiom, Tricho-derma and Rhizopus showed the lowest frequen-cy. Pathogenicity of the most frequent isolated fungi was proved and showed that pepper plants were attacked by F. oxysporum and R. solani. Pepper grown in rice bales showed better growth and increased fruit number and weight compared with those grown in natural soil. The pH around the roots in straw bales ranged from 6.3 to 6.6 which pored to be a slightly acidic substrate. However, the pH around roots in the natural soil ranged from 7.4 to 8.5, alkaline soil. So, sowing in rice straw can solve the conditions of alkalinity and salinity in rhizosphere of pepper plants. On the other hand, plants grown in rice bales recorded lower E.C. (1.75 Mmohs cm-1) value around the roots com-pared with the natural soil (2.55 Mmohs cm-1) at the end of the experiment. On the basis of the above results, it could be recommended that using rice straw bales as a growing media in replacing naturally infested soil, can improve the production of pepper under greenhouse conditions for expor-tation. Also, avoiding the serious environmental air pollution called the "Black Cloud" when disposed about 5 million tons of rice straw every year by burning.