Farm Advisor, Lynn Wunderlich searches for Gill's mealybug.
Mealybugs in Grapes
Mealybugs are tiny insects taxonomically placed in the Order Hemiptera; they are related to aphids and scale insects and are an important group worldwide for the damage they can do to agriculture crops.
- Mealybugs feed on plant phloem from many parts, often producing copious amounts of honeydew, which is often the first noticed sign of a mealybug presence.
Mealybug Honeydew on Grape Leaf. - Some species have the ability to transmit plant disease, such as leafroll virus.
- Mealybugs generally have flattened, elongated oval bodies that are covered by a powdery white wax. Species can be distinguished by the presence and length of body and anal filaments.
In the foothills, we have several mealybug species found in grapes. Growers who think they may have mealybugs should contact Lynn Wunderlich, UCCE Farm Advisor in El Dorado and Amador Counties at 530-621-5505 for identification and more information.
Mealybugs on bark
Click here for larger image of honeydew on grape leaf.
Click here for larger mealybug image.
General mealybug information:
Which mealybug is it, why should you care? By Lucia G. Varela, Rhonda J. Smith, Mark Battany, and Walt Bentley, University of California Cooperative Extension.
Practical Winery & Vineyard, January/February, 2006.
A good primer on distinguishing Grape, Obscure and Vine mealybug based on monitoring studies conducted in the North Coast, including timing for control.
Field identification of mealybugs on grapes. By Gillian Watson, CDFA taxonomist.
A handy picture id. guide to identifying the major species.
U.C. IPM website on mealybugs in grapes (Gill's mealybug is not yet included here. Contact Lynn for pesticide information updates.)
Sampling Program for Grape Mealybugs Improves Pest Management By Chris A. Geiger, Kent M. Daane, Walter J. Bentley, Glenn Y. Yokota, and Lee A. Martin. California Agriculture, May-June 2001.
Information on grape mealybug monitoring study with information on distribution of mealybugs on the vine at different times of the year, affecting management decisions.
Gill's mealybug
Gill's mealybug (Ferrisia gilli Gullan) - is an important mealybug recently established in El Dorado County. It is found on pistachios in the Southern San Joaquin Valley but is not known to be widespread on grapes in other areas of the state. It is a relatively large mealybug with a lot of fine waxy filaments on the adult stage, making it fairly easy to identify with a hand lens.
Gill's mealybug was misidentified as the "Striped mealybug" for several years until gene sequencing was conducted by P. J. Gullan and D. A. Downie to distinguish it. Striped mealybug does exist in California, mainly hosting on ornamentals. Ray Gill, retired taxonomist at CDFA, noted the differences between Striped and the Gill's mealybug, and Gills's mealybug, Ferrisia gilli, is named in his honor. Gill's mealybug is the correct common name for the mealybug found on grapes in El Dorado and, in order to avoid further confusion, "Striped mealybug" should not be used to refer to this insect.
Gill's mealybug has not been intensively studied in grapes so there is little known on its biology. We do not know the entire host range for this mealybug in the foothills or environmental requirements for it's growth. Studies are being planned for the 2008 growing season which will include grower cooperation and networking in order to understand and manage this mealybug.
Gill's vs. Grape Mealybug picture sheet.
A one page picture sheet showing the differences between adult Grape and Gill's mealybug.
A New Pest Species of the Mealybug Genus Ferrisia Fullaway (Hemiptera: Pseudococcidae) from the United States. By P.J. Gullan, D.A. Downie, and S.A. Steffan, 2003, Annals of the Entomological Society of America, Vo. 96, no. 6.
The scientific journal article describing Gill's mealybug morphology.
Ferrisia gilli Gullan, A Potential Pest of Grapes in California By Kris Godfrey, California Department of Food and Agriculture and David Haviland, UC Cooperative Extension, Kern County
Vine mealybug
Vine mealybug has been found in parts of Amador County but has not yet been found in El Dorado County. There is however a risk for it to become extablished in the foothills.
Vine mealybug link to Napa County website
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