1. CDFA Home
  2. Pierce's Disease Control Program
  3. Research Updates

Pierce's Disease
Research Updates

piercesdisease.cdfa.ca.gov

What is Pierce's Disease?

Pierce's Disease is a bacterial infection, which is spread by bugs that feed on grapevines, particularly the "glassy winged sharpshooter." Grapevines that become infected with PD can quickly become sick and die.

glassy-winged sharpshooter

IS THE GLASSY-WINGED SHARPSHOOTER PARASITOID GONATOCERUS ASHMEADI (HYMENOPTERA: MYMARIDAE) ONE SPECIES

  • Author(s): Hoddle, Mark; Stouthamer, R; Triapitsyn, Serguei; Vickerman, Danel;
  • Abstract: Gonatocerus ashmeadi Girault is a common and seemingly widespread egg parasitoid of glassy-winged sharpshooter (GWSS). Location records for G. ashmeadi indicate its natural range to be Florida, Louisiana, northeastern Mexico, Mississippi, North Carolina, eastern Texas (which coincides with the presumed native range of GWSS), and southern and central California (the adventive range of GWSS). Gonatocerus ashmeadi was collected from eggs of the native smoke-tree sharpshooter, Homalodisca lacerta (Fowler), as well as from GWSS eggs before G. ashmeadi releases began as part of an organized biological control program in CA. Gonatocerus ashmeadi is currently being imported from different areas within the natural range of GWSS and released in California with the assumption that this is one species and not a complex of morphologically indistinct sibling species. Species identifications have been made using light microscopy to determine the presence of key morphological features for G. ashmeadi. Light microscopy has failed to reveal any differences between different G. ashmeadi populations except for some specimens from central and southern Tamaulipas and San Luis Potos, Mexico (Triapitsyn et al. 2002). Due to the minute size of adult Gonatocerus parasitoids (1.2-1.7 mm in length), their taxonomic identification is very difficult without careful and costly preparation, which involves mounting on microscopic slides. The morphological characters that are used for differentiating between closely related Gonatocerus spp. can be variable and thus species limits are often difficult to assess without supporting data from biological and molecular data. The purpose of work proposed here is to determine whether G. ashmeadi in the native range of GWSS is one species or a complex of cryptic species that cant be separated on the basis of currently employed morphological characters. We intend to use three approaches to determine the species identity of different G. ashmeadi populations.
  • Publication Date: Dec 2002
  • Journal: 2002 Pierce's Disease Research Symposium

Navigation

Actions

Researcher Login

Sponsors