وضعیت آلودگی نسبت به نماتد ریشه گرهی در مزارع فلفل استان گیلان

Root knot nematodes (Meloidogyne spp.) are the limiting factors of cultivating agricultural products, including pepper. In order to evaluate the status of nematode’s infection, the pepper fileds of Guilan province were surveyed during 2016-2017 and their geographical distribution, infection rate and severity were assessed. To identify the species, the female posterior body rigion (Perineal pattern), morphology and morphometry of second-stage juveniles were used. The results indicated that root knot nematode is widespread in some of the pepper fields of Guilan province. The symptoms included stunting, yellowing, wilting of aerial parts and also the presence of gall on the roots. The appearance of these symptoms can lead to significant reductions in plant growth, delay in flowering and reduction in yields. M. incognita was determined as the dominate species in this study. Among the 40 surveyed fileds, 15 samples were recognized as infected samples. This indicates 37.5 % occurrence of nematode infection in this province. The disease severity in different regions was not the same amounts. and the population of second-generation larvae varied from 50 to 560 in 250 g of soil.The number of gall in infected roots was variable from 1 to 35 galls/g of roots and the population of second-stage juveniles varied from 50 to 560 in 250 g of soil. The average number of gall in infected roots was 27 galls/g of roots and the average of second-stage juveniles was 280 in 250 g of soil. Contamination with nematodes was recorded in Astaneh Ashrafieh, Lahijan, Langrood and Rudsar. Among them, Astaneh Ashrafieh had the highest rate of incidence (54.53%) and severity (92.9%). While, the least percentage of infection with the 15% incidence and 2.68% severity was observed in Langrood.