Oh my gosh! The other day the tomatoes looked so fabulous, and they were almost ripe. Today, they have little pockmarks and bad spots and are yellow and streaked. Some of the tomatoes are soggy and rotten. What happened?
Stink bugs might well be the culprit.
There are more than 200 varieties of this versatile feeder that feasts on a wide variety of produce from berries to pears to beans. Their favorite food, it seems, is tomatoes. (One of this pest’s cousins is the squash bug.)
The stink bug is a chameleon and changes color to blend into what ever it is sucking on. I even had one that was purple as it was feeding on my blueberries! They are reddish-brown when they feed on raspberries and they leave an off-taste on the fruit. But usually they are green or light brown.
They feed with a piercing, sucking mouthpart that causes the whitish-yellow corky spots underneath the skin of the fruit. The stink bug has a shield-shaped body about a 1/2-inch long. They emit an offensive odor when you handle them.
Stinkbugs can fly from plant to plant and can run very fast when you try to catch them. They drop to the ground and hide in debris.
Nearby weeds harbor the bugs both over the winter as well as during the growing season. Weeding your garden plot carefully, and not placing your garden near an untended area or where old boards and debris are stacked will get rid of the breeding places for this bug.
Planting flowers that attract beneficial bugs that feed on the eggs and the immature stink bugs also will help. Alyssum and plants in the parsley family attract lots of beneficials. I always leave a carrot and a parsley plant to over-winter and bloom the next season to attract the good guys. If you use an insecticide, you will kill any beneficials at the same time you are trying to kill the stinkbugs. If the stink bugs have a place to hide, your insecticide will not be effective.
Because it provides great hiding and breeding places, mulch can be detrimental around tomatoes as well as squash plants if your garden has an infestation of these pests.
You will recall how often I suggest an early-morning walk around the garden with your cup of coffee or a late-afternoon amble with an adult beverage. Daily assessment of the garden prevents insect populations from exploding out-of-control because you can catch and kill the first invaders. Often, when it gets hotter, the bugs migrate to your garden looking for moisture — especially the succulent ripening tomatoes.
The weapon of choice is a bucket of soapy water with a tablespoon of vegetable oil added in. Put on your garden gloves and handpick the stinkbugs and drop them in the bucket. If you are brave and ruthless, just smoosh the bugs between your glove-covered fingers. Shake the tomato plants and many of the bugs will fall off. Kill them. Don’t leave overripe fruit on the tomato plant; it is just an attractant for the bugs.
Look under the leaves near the veins for the whitish-pinkish cluster of eggs. Little roundish immature bugs may also be clustered near the barrel-shaped eggs. Either pick the leaf or wipe off all the eggs and youngsters into the bucket of water. Check for eggs in plants around the edge of the garden, especially in weedy areas. Sagebrush and arborvitae hedges are vectors that are home bases for stink bugs.
If the infestation is severe this year and many of the tomatoes are damaged, you need to think about next year. This fall, clean up debris and weeds and get rid of them because this could be the host for the over wintering adults.
Then next year, just as it gets warm at the end of June and as the tomatoes begin to ripen, start the daily search-and-destroy mission.
Good luck. Some years have more of the insects than other years. A good idea is to create a neighborhood watch so all of your neighboring gardeners are also doing their best to control stink bugs by eliminating weeds as well as the adults on the tomatoes.
A WSU Master Gardeners of Chelan County column appears weekly in the At Home section. Bonnie Orr is one of three columnists featured.