Evaluation of Japanese weed melon against the whitefly Bemisia tabaci (Gennadius) Middle East-Asia minor 1 (MEAM-1)

The whitefly Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) Middle East-Asia Minor 1, MEAM 1 (biotype B) is one of the most serious pests of cultivar melons, Cucumis melo L. (Cucurbitales: Cucurbitaceae), because it feeds on them and transmits disease viruses. We found that the Japanese weed melon JP 82,415 (JMG-16), derived from Megi-Jima Island in the Seto Inland Sea, Kagawa Prefecture, Japan, showed a very low preference for adult B. tabaci than other melons during cultivation in a greenhouse. In this study, we evaluated the resistance of JP 82,415 using choice tests, host-plant suitability tests, and trichome density. We compared it with that of a musk melon cultivar, Earl's favorite Harukei 3. Choice tests showed that B. tabaci has a lower preference for JP 82,415 than Earl's. Host-plant suitability tests showed that the number of F1 adults of JP 82,415 was small. JP 82,415 had fewer trichomes on the abaxial sides of the leaves, only about one-third as many as Earl's. The low density of trichomes may explain the non-preference of B. tabaci for JP 82,415. Thus, JP 82,415 is a promising novel material for developing melons resistant to B. tabaci.