Mating Disruption of Vine Mealybug in California Vineyards

The vine mealybug (VMB), Planococcus ficus, is a new key pest in California vineyards.
It was introduced into the Coachella Valley in 1994 and, by late 1990s, the pest was
found further north in California?s San Joaquin Valley (SJV). Currently, well-established
VMB populations are found in Riverside, Sacramento, Kern, and Fresno counties; and
new VMB infestations have been found in the North Coast and Central Coast regions.
Insecticides provide control, but are often costly and disrupt IPM programs for other
vineyard pests. To develop more sustainable control, we have been investigating develop
of a mating disruption program, based on the VMB sex pheromone. In both the 2003 and
2004 trials, we showed a reduction in pheromone trap catches in the pheromone-treated
plots. No differences were found between treatments if looking at the densities of VMB
using three minute counts on vines, during 2003, but overall differences were displayed
during 2004. We showed in both 2003 and 2004 that pheromone treatments performed
better in plots with lower VMB infestation levels. In 2003 trials, we found reduced crop
loss in four of five pheromone-treated plots (compared to control plots). During 2004, all
pheromone?treated plots had reduced crop loss. One reason for the reduced VMB
density may be a reduction in egg production, which was recorded in all pheromonetreated
plots (compared to the controls) in 2003 and 2004 trials. We also investigated the
VMB male flight periods for time of day and temperatures. Results show that male flight
is typically early in the morning, when temperatures are below 90°F, this information will
be used to improve the timing of pheromone application. To better understand the
mechanism of mating disruption on VMB population density, we isolated females (no
mating) and reared these specimens to the adult stage. An ovisac and crawlers were
produced, but there was lower egg production and more male VMB production. One
problem encountered was the longevity of sprayed pheromones, and we are working with
commercial operations to improve this aspect of the mating disruption program.
Information from the two season?s work indicates that mating disruption using
formulated pheromone sprays shows promise. In coordinated studies, we continued our
investigations of VMB sex pheromone for monitoring populations. For example, we
showed no significant impact between different commercially available lures or the effect
of trap color on the number of adult male VMB.