|Johnson, Marshall - UC RIVERSIDE|
|Morgan, David - CDFA, RIVERSIDE, CA|
|Morse, Joseph - UC RIVERSIDE|
Submitted to: Biological Control
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 29, 2009
Publication Date: October 1, 2009
Citation: Krugner, R., Johnson, M.W., Morgan, D.J., Morse, J.G. 2009. Production of Anagrus epos Girault (Hymenoptera: Mymaridae) on Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae) eggs. Biological Control. 51(1):122-129. Interpretive Summary: Anagrus epos is a natural enemy candidate for a biological control program targeting the glassy-winged sharpshooter (GWSS), Homalodisca vitripennis, in California. GWSS was first detected in California in 1990 and rapidly became responsible for spreading the bacterium Xylella fastidiosa among vineyards in California. Xylella fastidiosa causes Pierce’s Disease in grapes, which is one of the most economically important crops in California. Current management of the disease includes use of biological control agents to reduce GWSS populations in citrus groves, urban areas, and vineyards. Anagrus epos was recently imported to California, however, little is known about its biology or ecology when using GWSS eggs as a host. We report results from a series of laboratory assays revealing several aspects of A. epos biology that can be used to determine its potential as a natural enemy of GWSS when it is mass-produced and field released by insectary facilities. Studies on GWSS egg age preference for oviposition showed that A. epos females attacked all egg ages (1 to 8 days old), but preferred younger eggs (1 to 5 days old). At constant temperature, development from egg to adult ranged from 20 to 35 days and up to 14 A. epos adults emerged from each GWSS egg. Longevity studies showed that, if provided with honey and water, honey only, water only, or no food or water, adults lived on average 8.2, 4.7, 2.6, and 1.6 days, respectively. Understanding the basic biology and ecology of A. epos will allow greater numbers of parasitoids to be mass produced and released in California to potentially suppress GWSS populations and limit spread of X. fastidiosa to susceptible crops.
Technical Abstract: Anagrus epos Girault (Hymenoptera: Mymaridae) is a natural enemy candidate for a classical biological control program targeting the glassy-winged sharpshooter (GWSS), Homalodisca vitripennis (Germar) (Hemiptera: Cicadellidae), in California. Little is known about A. epos biology or ecology when using GWSS eggs as a host. Here, we report the results of laboratory studies that describe host age preference for oviposition, longevity of A. epos adults provided with different food sources, and developmental rates at six different constant temperature regimes. Anagrus epos is a gregarious parasitoid in GWSS eggs, with up to 14 adults emerging from each GWSS egg. In choice and no-choice tests for oviposition, A. epos females successfully parasitized all developmental ages of GWSS eggs (1 to 8 days old). In choice tests, parasitism rates were significantly higher in 1, 3, 4, and 5 day old GWSS eggs than in 2, 6, 7, and 8 day old eggs. If provided with honey and water, honey only, water only, or no food or water, A. epos females lived on average 8.2, 4.7, 2.6, and 1.6 days, respectively. Anagrus epos required 294.1 degree-days, above a lower temperature threshold of 12.4°C, to develop from egg to adult (eclosion). Our results provide baseline information useful in the development of an efficient parasitoid mass rearing program for A. epos release and evaluation in California.