Translator Disclaimer
1 February 2001 Seasonal Movement and Distribution of the Grape Mealybug (Homoptera: Pseudococcidae): Developing a Sampling Program for San Joaquin Valley Vineyards
Author Affiliations +
Abstract

The grape mealybug, Pseudococcus maritimus (Ehrhorn), is an important pest of table grapes in California’s San Joaquin Valley. The mealybug causes direct damage by infesting grape bunches, resulting in very low economic injury levels. To develop a sampling program to help growers predict damage and make control decisions, we destructively sampled six entire grapevines each month to determine mealybug abundance and within-vine distribution. These absolute counts were then used to evaluate several relative sampling methods: sticky tape barriers on canes, excised spur samples, standard-sized pieces of bark, timed counts, and nondestructive counts on spurs. At midseason we sampled additional vines to correlate mealybug numbers with economic damage at harvest. Finally, mealybug life stages and natural enemies were recorded throughout the study. Timed 5-min counts show the strongest correlation with total mealybug numbers, and a simple count of mealybugs on three spurs per vine at midseason is the best predictor of economic damage. Mealybugs completed ≈2.5 generations in 1998. Comparison to data on mealybug development suggests that exceptionally long growing seasons could exacerbate infestations by allowing the completion of a third generation. No mealybugs were found on bunches before early August, when second-generation crawlers moved out of the bark. Grape bunches that touched old wood had significantly higher damage and mealybug densities. The majority of mealybugs were always found in protected locations (under the bark of the trunk, spurs or canes), indicating the need for chemical or biological controls that can penetrate these refugia.

Chris A. Geiger and Kent M. Daane "Seasonal Movement and Distribution of the Grape Mealybug (Homoptera: Pseudococcidae): Developing a Sampling Program for San Joaquin Valley Vineyards," Journal of Economic Entomology 94(1), 291-301, (1 February 2001). https://doi.org/10.1603/0022-0493-94.1.291
Received: 6 December 1999; Accepted: 1 August 2000; Published: 1 February 2001
JOURNAL ARTICLE
11 PAGES

This article is only available to subscribers.
It is not available for individual sale.
+ SAVE TO MY LIBRARY

SHARE
ARTICLE IMPACT
RIGHTS & PERMISSIONS
Get copyright permission
Back to Top