STUDIES ON SURVEYING NEMATODES, HOST SUITAPILITY AND CONTROL OF Meloidogyne incognita ON GRAPEVINE BY CERTAIN COMPOUNDS WITH REFERENCE TO NEMATODE INVESTATION AND YIELD.

Percentage of frequency occurrence, population density and prominence value were determined for the plant  parasitic nematodes associated with some grape varieties in Behira governorate. Data revealed that stunt nematodes Tylenchorhynchus spp. and the rootKnot nematode Meloidogyne spp. were found with highest prominence value on Flame, King-Ruby, Perlette, Superior and Thompson varieties as compared to other nematode genera. Host suitability of varieties Early Superior, Flame, King Ruby, Perlette, Superior and Thompson to infection of root- knot nematode  M. incognita was tested under greenhouse conditions. The varieties Early Superior, Flame and Superior were rated as susceptible hosts. The relationship of grapevine yield to M. incognita  densities was studied. Five grapevine varieties were tested to carry out the experiment in South Tahrir. Association between  M. incognitadensities and yield was variable, even when the vines were separated according to vigor of vines, varieties and yield. The highest density of M. incognita was associated with the medium yield while the low densities of M. incognita associated with the low production of all varieties except Thompson variety. The result showed that the high production trees were more infected than low production trees in the same variety as shown with King Ruby and Flame. Biological treatments i.e. Diple 2x, EM1 and mycorrhyzal fungi (Glomus spp.) as well as certain organic soil  amendments namely chopped garlic cloves, (Allium sativum) and dried powdered leaves and stems of liquor ice (Glycyrrhiza globra L.) and chamomile (Matricari chamomile) were examined for controlling M. incognita infecting Superior variety. Results indicted that all treatments showed significant effect in reduction of galling and reproduction of M. incognitaon grapevine as compared to untreated trees. However the application of chopped garlic cloves at the rate of 80 gm/ tree gave the highest reduction in galling and reproduction of  M. incognitawas followed by mycorrhyzl fungi (Glomus spp.) at the rate of 1ml/ 100ml water as compared to control treatment while the least effect was recorded with dried powder of chamomile plant at the rate of  40 gm / tree . The most tested treatments significantly reduced nematode reproduction of M. incognitain soil and roots of grapevine cv. Superior compared to the untreated check.