Peranan strain pineapple mealybug wilt associated virusdan kutu putih dalam menginduksi gejala layu pada tanaman nanas

Abstract

ARTA JUNITA HUTAHAYAN. The Role of Pineapple Mealybug Wiltassociated Virus Strain and Mealybug (Dysmicoccus spp.) in Inducing Wilt Symptom on Pineapple Plants. Dibimbing oleh GEDE SUASTIKA dan SOBIR Indonesia is a tropic country which have potential to produce exotic fruits like pineapple. Pineapple is very important fruit for world trade. Indonesia is the third largest pineapple tin exporter after Philippine and Thailand. The main problem in pineapple cultivation is wilt disease. Mealybug wilt of pineapple (MWP) is currently present in pineapple-growing areas of West Java, Indonesia. MWP is characterized by severe tip dieback, downward curling, reddening, and wilting of the leaves which can lead to total collapse of the plant. Mealybug feeding on the pineapple plant has been associated with MWP symptom. Furthermore, flexuous rod-shaped virus particles, designated Pineapple mealybug wilt-associated virus (PMWaV) have been isolated from both symptomatic and asymptomatic pineapple plants. PMWaV is actually a complex of at least two different viruses, PMWaV-1 and PMWaV-2 that are transmitted by mealybug. The objectives of this research are to study the role of PMWaV isolates infection and mealybug feeding in inducing wilt symptom on pineapple plants, and to study the incidence of MWP in pineapple-growing areas of Indonesia. Survey for MWP were conducted in pineapple production areas of East Java (Blitar), West Java (Subang and Bogor), and North Sumatera (Simalungun). The incidence of the disease in all of the areas surveyed were found to be ranging from 50% to 90%. These results indicated that MWP has already spread widely in pineapple-growing areas of Indonesia. Transmission of PMWaV from infected pineapple plant to the pineapple test plants using mealybugs Dysmicoccus spp. under greenhouse condition were successfully conducted. The symptoms on the test plants were the same as that on naturally infected plants. The plants inoculated with virus and colonized by mealybug produce more severe symptoms than the plants inoculated with virus only. This indicated that PMWaV infection and mealybug feeding play important role in inducing wilt symptom. But, some pineapple plants surveyed on the field showing MWP symptoms without colonized by mealybug. This finding suggested that PMWaV likely to be the most important causal agent of the MWP, and mealybug feeding making the symptom more severe.