Submitted to: BARC Poster Day
Publication Type: Abstract Only
Publication Acceptance Date: April 1, 2000
Publication Date: N/A
Technical Abstract: Encarsia formosa, a larval endoparasitoid of several whitefly species, is a valuable biological control agent for greenhouse whiteflies. Since 1926, it has been successfully used to control this pest in greenhouses. In order to develop an in vitro system for mass rearing this wasp, host-parasitoid interactions between E. formosa and its whitefly host must be elucidated. The existence of this wasp has been known for 80 years, however little information is available concerning the regulation of its development or that of its host. E. formosa is able to parasitize and complete development in all four instars of the greenhouse whitefly. Parasitoid development was significantly slower when 1st and 2nd instar hosts were parasitized than when 3rd and 4th instars were parasitized. We found that embryonic development was considerably longer in hosts parasitized as 1st or 2nd instars than in hosts parasitized as 3rd or 4th instars. Regardless of host instar parasitized, the parasitoid molt to the 3rd instar was never observed until the greenhouse whitefly reached stage-5 of the 4th instar. Host instar parasitized did not significantly affect the dimensions of E. formosa, percent adult emergence, or adult head width. E. formosa adults had a significantly longer life span when 3rd and 4th instar greenhouse whiteflies were parasitized than when 1st and 2nd instars were parasitized. The adult parasitoid emergence was more synchronous when 3rd or 4th instar hosts were parasitized than when 1st and 2nd instar hosts. This is the first study to track E. formosa's growth and development in hosts parasitized as different instars and to examine the effects of host developmental stage on parasitoid maturation.