Biology of meloidogyne incognita on its host plants and resulted biochemical alterations
2011
Mahfoud, N.A.
The life cycle of Meloidogyne incognita on tomato, sunflower, pepper, cowpea, okra and soybean was studied under two different temperatures. The nematode required 28 days at 32+-5 °c to develop and produce 2nd stage juveniles of the next generation on tomato, okra, pepper and cowpea, 21 days on sunflower, 35 days on soybean. At lower temperature (20:i: 5 °C), however, it required 35 days in tomato, sunflower, okra, soybean, 42 days in cowpea and 49 days in pepper. Concerning the effect of organic and inorganic fertilizers and nemacur 10% G on M incognita reproductively on tomato, all treatments significantly reduced nemato'de build up and ameliorated tomato growth. The nematicide, neem (dry leaves) and compost 1, 3 at high doses (5 glpot) gave the best results. Nematode infection reduced root content of total soluble sugars, increased amino acids, total phenol and tannins but the opposite was the case in all treatments. In shoots, nematode infection reduced soluble sugars, total carbohydrates and total amino acids and all treatments recompensed such reduction. Nematode infection impaired tomato up take of N, P and K but treating plants with organic and inorganic fertilizers provoked their up take. All treatments increased antioxidant substances in tomato (shoot and root) comparing to healthy and untreated infected plants but decreased oxidant substances. Sandy soil was more favorable to nematode infection and reproduction than loamy soil regardless of host plant. Reduction in plant growth due to nematode infection was more pronounced in sandy soil. Biochemical alterations in tomato, sunflower and cowpea resulted from nematode infection in relation to soil type indicated that shoots content of total soluble sugars and N, P, K reduced in sandy soil, but total phenols increased in infected roots. Tannins and reducing sugars decreased in infected roots in loamy soil.
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