Morphological and Molecular Diagnosis of Root-Knot Nematodes on Okra with Evaluation of the Efficacy of Olive, Sesame and Garlic Extract for Disease Control

Abstract

This study aimed to isolate and diagnose root knot nematodes on the okra plant based on the phenotypic diagnosis according to the perineal pattern and the polymerase chain reaction (PCR) method, and toevaluate the efficiency of olive stock, sesame, garlic extract, and the chemical pesticide Voual 24 SL in controlling the disease. The phenotypic diagnosis based on the perineal pattern showed that the diagnosed nematodes belong to Meliodogyen Incognita. The results of the Molecular diagnosis (PCR) were also confirmed by using the initiator Mel F/R to detect the S rDNA18 gene. The results of the partial diagnosis showed isolateion belonged to the nematode M. Incognita. A new Iraqi isolate was recorded in the global gene bank under number a (MW737418.1). The results of applying the following treatments Voual 24 SL, garlic extract, olive stock and sesame meal showed a reduction in complexity index and improvement in growth characteristics and plant yield. The Voual 24 SL pesticide and garlic extract treatment recorded a reduction in complexity index of 1.49, 1.83 and the highest plant height and plant yield recorded by the garlic extract treatment was 54.66 cm. The highest weight of wet roots was recorded in the treatment of sesame meal, which was 13.45 gm.