Submitted to: National Research and Action Plan for Silver Leaf Whitefly
Publication Type: Abstract Only
Publication Acceptance Date: 12/21/1999
Publication Date: N/A
Technical Abstract: APHIS studies effectiveness of exotic species of Eretmocerus from Pakistan, Spain, United Arab Emirates & Ethiopia, to augment limited parasitism by native U.S. Eretmocerus. Assessment of these studies requires identification of parasitizing Eretmocerus. Small size & similar morphology make identification of adults difficult & early-stage larvae within the whitefly nearly impossible to detect & distinguish. We characterized satellite DNA sequences from 2 foreign species, E. mundus (Spain) & E. hyati (Pakistan), & one native U.S. species, E. eremicus. Also developed a DNA probe for the greenhouse biocontrol agent, Encarsia formosa. Each characterized sequence comprised 1-3% of the genome. Lengths of repeat units in each sequence: E. mundus (#3), 172 bp; E. mundus (#7), 348 bp; E. hyati, 251 bp; E. eremicus, 144 bp; & E. formosa, 33 bp. DNA probes from E. eremicus & E. formosa are specific and the probe from E. hyati is nearly specific (3% cross reaction with E. emiratus). E. mundus probe hybridizes with genome of all foreign species tested, but not with E. eremicus or E. tejanus; thus, it is useful for differentiating between foreign & native U.S. species of Eretmocerus. DNA probes were successfully evaluated for detection of parasitism in whitefly nymphs from cotton fields where Eretmocerus sp. (Ethiopia) had been released.