SURVEY OF VIRUSES ASSOCIATED WITH FIELD-GROWN SWEET MELON (Cucumis melo L.) IN GOMBE STATE, NORTH EAST NIGERIA.

Abstract

A survey of farmers’ fields of sweet melon (Cucumis melo L.) showing virus - like symptoms was carried out to determine the incidence and severity of viruses associated with the crop in three local government areas of Gombe State, North east Nigeria in 2014 and 2015. A total of1440 leaf samples from 72 farmers’ fields were collected. The leaf samples were indexed for Melon necrotic spot virus (MNSV),Cucurbits chlorotic yellows virus (CCYV), Cucurbits yellow stunting disorder virus (CYSDV), Zucchini yellow mosaic virus (ZYMV),Cucumber mosaic virus (CMV) and Watermelon mosaic virus (WMV)using Double antibody sandwich enzyme- linked immuno-sorbent assay (DAS- ELISA). Plants from all the fields surveyed exhibited typical virus disease symptoms such as, chlorosis, necrosis, yellowing, mottling, leaf curling, mosaic and vein banding. The most prevalent virus symptom observed in the surveyed fields was mosaic followed by yellowing, leaf curling while necrosis recorded the least virus disease symptom. Virus disease symptom severity recorded, ranged between 2(mild) and 5(severe). Among the six viruses detected on the surveyed leaf samples by ELISA, ZYMV was the most prevalent in both dry and rainy seasons, in all the three local government areas. It occurred in 11 out of 12(97.5%), followed by CMV, WMV, CYDV and CCYDV with mean percentage occurrence of 83.3%, 63.6%and33.3% respectively, of the locations. MNSV was the least encountered virus with mean percentage incidence of 25.0%. Zucchini yellow mosaic virus, CMV, WMV, (Potyvirus), CYDV and CCYDV Nigerian Journal of Plant Protection (NJPP) Vol. 32, No 1 June 201888(Crinivirus) were detected for the first time on sweet melon in Northeast Nigeria.