Jerry Brust, IPM Vegetable Specialist, University of Maryland; jbrust@umd.edu
I have seen a great deal of stink bug damage to tomato fruit this year-more than usual (Fig. 1). The fruit has the characteristic white spots that when peeled back reveal spongy white areas. As the fruit turns red these white areas turn yellow (Fig. 1). When adults, or especially nymphs, feed on the fruit they create a star burst pattern in the surface of the fruit. I guess the surprise is that I have found very few if any Brown marmorated stink bugs (BMSB) in any of these tomato fields. Almost all of the stink bugs have been brown stink bugs (Euschistus spp), although lately (last 2 weeks) I have seen more green stink bugs. There have been very few reports or observations of BMSB being much of a problem so far this year in vegetables. Adult brown stink bugs are grayish-yellow to light brown with dark punctures on their back (Fig. 2). They DO NOT have two white spots on their antenna as do BMSB. Adults overwinter in woods, fence rows and under the bark of trees. A female oviposits a total of about 60 eggs over the summer. The nymphs, which are pale green, develop through five instars and require about one month for development. Because the adults are strong fliers they rapidly can move between hosts. Brown stink bugs are very difficult to scout for and often the only thing that is seen is the damage they cause to large green or ripening fruit. Stink bugs are difficult to control even when found as it takes several applications of insecticide to reduce their numbers (see the Commercial Vegetable Production guide for recommendations). Some of the most heavily fed upon fruit had very dark areas that when cut into appear as a dry rot (Fig. 3). What microorganisms are in this dry rot area is something we are looking into. It appears that our native stink bugs can inject microorganisms almost as readily as do BMSB when they feed.
Figure 1. Stink bug feeding on tomato, yellow areas when cut reveal spongy white cells
Figure 2. Brown stink bug, Euschistus, spp.
Figure 3. Internal dry rot caused by very heavy stink bug feeding