Garden Help Desk: Aphids cause problems for various plants | News, Sports, Jobs
When black currant aphids feed on current leaves, they can cause sucking, bending, and discoloration. (Courtesy photo)
Like many other aphid species, black currant aphids can produce a winged generation. (Courtesy photo)
Woolly elm aphids leave their hosts in serviceberry and in late summer and fly to elm trees where they lay their eggs in bark crevices to overwinter. (Courtesy photo)
Woolly elm aphids produce a generation when it is time to migrate from their spring host to their summer host (serviceberry), and then again in the fall to return to elms for the winter. (Courtesy photo)
Woolly elm aphids abound at the base of Zelkova. (Courtesy photo)
I planted a lake red currant bush this spring. I thought he was just having a hard time establishing himself, but I finally took a closer look at him, then looked at a fact sheet about the expansion, and I think I both aphids and currant flies. I have attached some photos. Does this sound like the problem? Is there something I need to do this time of year?
It looks like black currant aphids, but dark winged insects look more like winged aphids than black currant fruit flies. This is the time of year when aphids produce a generation of winged aphids which mate and lay eggs to overwinter on the stems.
There are some things you can do to reduce your aphid problem in the next year. Next spring, when the buds start to swell (but before the leaves come out), spray your bush with a spray of dormant oil. This will suffocate many overwintering eggs.
During the growing season each year, don’t wait to see aphid damage on your gooseberry bush. Instead, explore the bush at least 2-3 times a week for aphids. Check the underside of the leaves and at the first sign of aphids start using control measures.
Many times aphids can be controlled by watering them with heavy sprays of water several times a week. If that doesn’t work, applying insecticidal soap every week or two for several weeks should help. Insecticidal soap only works on contact, so full coverage is important, especially on the underside of the leaves.
The tender, lush growth is attractive to aphids. To reduce the risk of aphids on your gooseberry bush:
- Avoid over-fertilizing – a moderate application of nitrogen in the spring will suffice.
- Avoid overwatering – a deep soaking once a week in the summer, and less often in the spring and fall, is sufficient for your currant.
- Remove all suckers at the base of your bush each season to eliminate those attractive feeding sites
- Prune away excess overcrowded growth in your currant’s canopy to reduce humidity in the bush and discourage aphids.
We have a bug invasion. There are millions of bugs around the base of our trees in our front yard and in the air and on the bark, but I haven’t seen them preying on the leaves. I would like to know if these are dangerous for our trees and how to control them.
These look like woolly elm aphids. Aphids’ bodies have a waxy coating that can make them appear cottony or dark. You see them on your trees because zelkovas are members of the elm family.
Woolly elm aphids spend early spring on elms, then move off in mid-summer to spend the summer on their alternate host, serviceberry. In the fall, a generation of woolly winged elm aphids is produced, and this generation returns to the elms to lay eggs that will overwinter and hatch in the spring.
The woolly elm aphid feeds on serviceberry roots during the summer and the feeding can damage the roots and affect plant vigor. The spring aphid that feeds on elms, including zelkovas, can be unsightly, causing leaves to warp or curl, but it usually does not affect the health of elms.
You have a few control options if you want to reduce their population.
- You can water them with heavy sprays of water every day for a few weeks. It won’t kill all aphids, but it will reduce their numbers and won’t involve chemicals if that’s your preference.
- You can spray them with insecticidal soap if you want to reduce damage to beneficial insects that may be on the tree. Spray about once a week for a few weeks or until you only see a few aphids. Insecticidal soap only works on contact, so full coverage is important.
- You can spray the trees with permethrin or another pyrethroid. It will also kill all other insects, including beneficial insects, on the trees. Read the label on the product and follow the directions carefully.