Every year it seems there is a new “pest du jour” to combat. In Napa County, we've had the olive fruit fly, glassy-winged sharpshooter, European grapevine moth and vine mealybug. Now we have the brown marmorated stink bug (Halyomorpha halys) or BMSB.
Last fall, several Napa County Master Gardeners volunteered to participate in a survey conducted by the Kent Daane Research Laboratory at U.C. Berkeley. The researchers were patrolling Napa County for the stink bug, an invasive pest, and needed diversified gardens that contained vegetable and fruit crops as well as some fruiting and ornamental trees. I volunteered to participate.
The lab's representative dutifully showed up every week to inspect my garden and a pheromone trap that had been placed in one of my trees. The initial survey lasted about six weeks and uncovered no sign of the BMSB. So far, so good. In May, the survey resumed with the placement of another pheromone trap and more weekly inspections.
In early June, I was sitting at my desk when I noticed Greg Clark, Napa's Agricultural Commissioner, poking around in my trees. I thought it was unusual for Greg to be making house calls, so I wandered outside to see why I was being honored with a personal visit. The reason was not good. Researchers had found evidence of Napa County's first BMSB in the pheromone trap in front of my house.
Being the home of the first BMSB in Napa County is a dubious distinction to say the least. I had heard of the little critter but did not know much about it. Nor did I know what to do now that it had been discovered in proximity to my vegetable garden, fruit trees and vineyard.
So far I have learned the following:
- It is not a “little critter.” At maturity it is 5/8 inch long.
- Crop damage by BMSB can be severe as one bug can feed on many fruits. Adults and nymphs suck juices from fruit and seeds, creating pockmarks and distortions that make the harvest unmarketable. Damaged flesh under the skin turns hard and pithy. BMSB damages tree fruits, berries, grapes, legumes, vegetables and shade trees.
- Management options are limited. Chemical and biological controls require further testing. Hand picking may be the best control. I'm sure my wife won't mind patrolling the garden and fruit trees and hand picking BMSBs.
- On the positive side, the bugs are not harmful to people, pets or structures. They do not bite, sting, suck blood or spread disease.
The Agricultural Commissioner's office has hung more pheromone traps around my property, and visiting the traps daily is now part of my routine. To make matters worse, these good people discovered evidence of the vine mealybug in my vineyard when they were checking the BMSB traps recently.
With the 20 or so yellow sticky traps I've placed in my olive trees to monitor fruit fly activity, it looks like I've been visited by the pest version of Typhoid Mary. Any day now, I'm expecting four people wearing masks and protective clothing and carrying large spray guns—the Pestbusters—to show up and take care of these problems.
[Ed: The photos show the egg clusters and the bugs, along with the kind of damage they do to the crops Napa County gardeners grow.]
Tree Walk: Join U. C. Master Gardeners of Napa County for a free guided tree walk through Fuller Park in Napa. Registration is recommended as space is limited. Meet at Fuller Park, corner of Jefferson and Oak Streets. Online registration or call 707-253-4221. Trees to Know in Napa Valley will be available for $15. Cash or check payable to UC Regents. Sorry, we are unable to process credit cards.
Workshop: The U. C. Master Gardeners of Napa County will host a workshop on “Growing Fall and Winter Vegetables” on Saturday, August 13, from 9:30 a.m. to 11:30 a.m., at the University of California Cooperative Extension, 1710 Soscol Avenue, Napa. Discover the joy of harvesting vegetables from your own garden in fall, winter and early spring. Topics will include timing, watering, fertilizing, managing pests and harvesting. On-line registration (credit card only). Mail-in/Walk-in registration (cash or check only).
Master Gardeners are volunteers who help the University of California reach the gardening public with home gardening information. U. C. Master Gardeners of Napa County ( http://ucanr.edu/ucmgnapa/) are available to answer gardening questions in person or by phone, Monday, Wednesday and Friday, 9 a.m. to Noon, at the U. C. Cooperative Extension office, 1710 Soscol Avenue, Suite 4, Napa, 707-253-4143, or from outside City of Napa toll-free at 877-279-3065. Or e-mail your garden questions by following the guidelines on our web site. Click on Napa, then on Have Garden Questions? Find us on Facebook under UC Master Gardeners of Napa County.