Backyard Gardener: Stink bugs and woolly adelgids

Hello Mid-Ohio Valley Farmers and Gardeners! Rain and cool weather have hit the Valley this week, almost feeling like an early fall. Labor Day is coming soon, marking the end of summer. The moisture has definitely kept all of our pasture and hayfields green and growing but has been a challenge for farmers trying to make hay.

As summer fades I hope many gardeners are planting fall crops to be harvested in late fall and early winter including lettuce, spinach, carrots and kale and many cole crop such as kale, cabbage, broccoli and Brussels sprouts. Many of these vegetables will improve in flavor with cooler weather or a few light frosts.

The tomato harvest continues and this week I am discussing stink bug damage on this crop. Many tomato growers are seeing stink bug damage this summer. The Brown Marmorated Stink Bug can present a challenge to both backyard gardeners as well as commercial growers. Even low populations can produce noticeable damage to tomatoes rendering them unmarketable or very unappealing to be eaten even by home gardeners.

Both nymphs and adults use their piercing-sucking mouthparts to puncture the epidermis and extract plant juices from tomatoes. On green tomatoes, the damage may appear as whitish spots with indistinct borders. Although the spots may only measure 1/16 – 1/2″ in diameter, they can merge to affect large areas of the fruit. On ripe tomatoes, the damage appears as hazy golden yellow spots. Stink bug damage may be superficial with little impact on the tomato flesh. While damaged tomatoes are still edible, their unsightly appearance reduces their marketability. However, heavy feeding may produce areas with whitish, spongy tissue, and feeding sites can initiate infections causing fruit to be discarded. Heavy damage can occur before gardeners realize they have a significant bug problem due to the sudden appearance of damage to ripening tomatoes.

There’s also a challenge with a limited number of insecticides labeled for use on ripening tomatoes. You must always read and follow label directions paying particular attention to the time between the application and the harvest of vegetables called the “harvest interval.”

Do not use traps thinking they will protect your vegetables. Research conducted by the University of Maryland showed they actually invite more bugs to the tomatoes. Furthermore, if you’re growing tomatoes on the patio or deck, keep the outside lights turned off at night. They only attract insects to your plants.

I also want to mention a danger to many of our local forests, properties and homes, the hemlock wooly adelgid. This tiny insect is posing a large threat in West Virginia. The hemlock woolly adelgid is a small, aphid-like insect native o Asia, which threatens he health and sustainability Eastern and Carolina hemlock trees and has the potential to upset entire wildlife habitats.

Adelgids appear on hemlock branches and look like tiny cotton balls, averaging approximately 1/16 inch in length because of the white, wool-like substance they produce over their bodies. They feed at the base of hemlock needles and drain the sap causing the needles to fall off, which eventually leads to premature death of the tree.

The insect was first reported in the eastern United States in 1951. Areas along the Appalachian Mountains have experienced significant mortality of eastern hemlock due to this devastating insect.

West Virginia’s state parks and forests will be at risk for severe damage if they are not controlled. The insects can be spread by birds and other animals. Frequently checking hemlocks for infestations is essential to prevent adelgid populations from building to damaging levels.

Larger trees can be treated with a systemic product that is absorbed by a plant and moved throughout its tissues. Systemic insecticides can be applied as a soil drench, soil injection or tree injection.

Contact me at the Wood County WVU Extension Office at 304-424-1960 with questions. Good Luck and Happy Gardening!