الفهرس 
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Abstract
Occurrence % (Relative frequency) of different nematode genera associated with grapevines planted in sandy soils at Samalot district, Minia Governorate was determined during 2018 season. The total number of the collected samples were 120 samples. Root knot nematode represented in 108 samples, with an incidence rate of 90%.Spirale nematode Helicotylenchus spp. outperform all with a 100% incidence rate. Needle nematode Longidorus spp. as well as lance nematode Hoplolaimus aegypti were almost equal in incidence, 56.7% and 53.3%, respectively, while lesion nematodes and citrus nematodes showed a frequency of 80% and 90% in the samples, respectively. The lowest occurrence rate was the dagger nematode Xiphinema sp., recording an occurrence rate of 33.3%. In clay loam soil root knot nematode represented by 63.3 % from the total samples (120 samples) by 29.7 % reduction than in sandy soil. Spiral nematodes were found in 80% of the total samples by reduction 20% than in sandy soil. Needle nematodes recorded relative frequency of 30% by up to 47% less than its presence in sandy soil. Lesion nematode was present in 36.7% of the total samples, with a rate of 54.1% lower than that in sandy soil. The incidence of citrus nematodes in the total samples was approximately 83.3% in clay soil, compared to its occurrence in the total sandy soil samples at 90.0%, with a slight decrease rate of 7.4%. Lance nematode presented in 30 % of the total samples in clay loam soil versus 53.3 % in sandy soil by declining rate of 43.7 %. Dagger nematode was found in 10% from the total samples collected from clay loam soils in comparing to 33.3 % occurrence percentages in sandy soils. That mean reduction occurred by 70.0% .
Relative densities and relative biomass of nematode genera associated with grapevines cultivated in sandy soil during 2018 season in Minia Governorate show that the number of root-knot nematodes in 120 samples was 12,806 out of the total number of all nematode genera (45041), with a percentage of 28%, and the number of spiral nematodes was 16339, with a percentage of 36%. For needle nematodes and spear nematodes, their relative density values were close, recording 7% and 6%, respectively Also, the lesion nematode and the citrus nematode were close in their relative densities, recording 10% and 11%, respectively. The lowest relative density 2 % was recorded by the dagger nematode. The estimated relative biomass were 83.29, 0.325, 9.840, 0.117, 1.806, 1.809 and 5.408 with root-knot, spiral, needle, lesion, citrus, lance and digger nematodes, respectively. The importance of each nematode genus was calculated by summing the frequency, proportions, relative density, and relative biomass of each nematode genus. The results showed that the highest importance values were recorded with the root-knot nematode, then the needle nematode, followed by the dagger nematode, with values of 84.46, 10.48, and 5.758, respectively. Other nematode importance in descending order were 2.816, 1.685 and 1.017 with citrus, spiral and lesion nematodes, respectively
Samples obtained in the same season 2018 from clay loam soils contained the same nematode genera but with different relative densities. These relative densities were 0.26, 0.20, 0.11, 0.13, 0.11, 0.09 and 0.10 for Meloidogyne spp., Helicotylenchus pseudorobustus. ,Longidorus sp. Prtylenchus thornei, Tylenchulus semipenetrance, Hoplolaimus aegypti and Xiphinema sp., respectively. These results revealed the superiority of Meloidogyne spp. and the retardation of Hoplolaimus aegypt. The estimated importance values of the detected nematode genera revealed excel of Meloidogyne spp. that recorded importance value of 84.18 and retardation of Pratylenchus thornei (0.617)..
Occurrence of plant parasitic nematodes associated with grapevines in fruiting period at Samalot district, Minia Governorate was detected in sandy and clay loam soils during 2019. Occurrence percentages of all detected nematode genera in sandy soil were high than other recorded in clay loam soils.. The more occurred nematode genera was Helicotylenchus in both sandy and clay loam soils. The least frequency in samples was dagger nematode, Xiphinema sp. By calculating the relative density and relative biomass of the nematode genera present in vineyards in sandy soil during the 2019 season, the results showed the superiority of Helicotylenchus pseudorobustus in its relative density (0.35), while the highest value of relative biomass (83.29) was recorded with Meloidogyne spp. The estimated importance values of nematode genera associated with grapevines in sandy soil during 2019 revealed the excel of Meloidogyne spp. recording importance value of 84.55 versus the least value of importance ,1.097 with Pratylenchus thornei.
As for relative densities of nematode genera in clay loam soil during 2019, root- knot nematode surpassed other genera in relative density it recorded 0.28 followed by spiral nematodes (0.22) while, citrus and lance nematodes were retarded and recorded relative frequency of 0.09. from data obtained previously the importance value indicate to the high importance value of Meloidogyne spp. recording 84.14 and less importance value was with Pratylechus thornei .