Host Plant Preference of Liriomyza sativae (Diptera: Agromyzidae) Populations Infesting Green Onion in Hawaii

Abstract

Liriomyza sativae Blanchard was the only agromyzid leafminer species reared from foliage of green onion, Allium cepa L. var.‘aggregatum’, collected at two commercial farms in the Waianae area of Oahu, HI. Mean weekly densities of live leafminers reached levels > 13 larvae per leaf with mean seasonal densities of total mines as high as 20.6. In laboratory-conducted host plant-preference (choice and no-choice) tests, adult female L. sativae colonized from the Waianae and Hawaii Kai areas of Oahu exhibited significantly greater host feeding and ovipositional preferences for foliage of ‘Henderson’ bush lima bean, Phaseoluslimensis var. limenanus L. H. Bailey, compared to ‘multiplier’ onion. In no-choice tests, Waianae L. sativae reared on onion and bush lima bean deposited significantly more eggs in onion compared with bean-reared Hawaii Kai L. sativae. However, when given a choice between onion and bean, preferences of bean-reared Waianae L. sativae were not significantly different from Hawaii Kai L. sativae. Onion-reared L. sativae preferred onion significantly more than bean-reared L. sativae when provided a choice of the two host plants. Green onion has not been reported previously as a common host of L. sativae. Based on differences in feeding and ovipositional preferences of Waianae L. sativae compared with Hawaii Kai L. sativae, it was concluded that Waianae populations of L. sativae had broadened their host range to include green onion. Factors conducive to host plant expansion of L. sativae populations in the Waianae area of Oahu are discussed.