UC Riverside

The Eucalyptus gall wasp, Ophelimus maskelli, is a significant pest in areas throughout

the world. Heavy galling significantly weakens trees as well as causing early defoliation leading

to premature death. Eucalyptus species are grown all over the world for various uses including

fuel and paper making. The plants are especially prized in plantations for their rapid growth and

development. O. maskelli was recently discovered in southern California along with two

associated parasitoid wasps. Closterocerus chamaeleon is a known parasitoid of O. maskelli and

has been intentionally introduced in areas of Israel as well as throughout the Mediterranean for

use as a biological control agent. The second parasitoid wasp, Selitrichodes neseri, has been

intentionally introduced in South Africa as a biological control agent for another Eucalyptus gall

wasp, Leptocybe invasa. Phenologies of each species in southern California are recorded and

discussed using two different collection methods. Comparisons are made between species,

inland and coastal populations of southern California, and populations in Israel. Morphological,

molecular, and ecological data are combined in the description of a new strain of S. neseri in

southern California. Our studies discuss ecological relationships between these three wasp

species as well as provide a groundwork for further research involving the adjustment of

invasive species to a new environment.