From University of Maryland Extension:
Woolly Aphids. Steve Black is finding woolly aphids on [Hawthorn] Crataegus ‘Crusader’. These aphids produce a lot of white wax to cover their bodies. The populations are very noticeable at this time of year.
Control: Woolly aphids are pretty easy to control with most contact chemicals including insecticidal soap, horticultural oils, and neem oil. Look to see if predators such as syrphid fly larvae are present and feeding on the aphids. If enough of these predators are present on a plant and appear to be controlling the problem, it would be best to avoid any spraying at all and let the larvae
clean up the problem.
Oleander Aphids
Another common aphid found at this time of year is the oleander aphid on various species of Asclepias. Aphids are covering stems on several Asclepias incarnata plants here at the research center. The rain this week washed some of the aphids away, but plenty are still left on the plants. There were a few syrphid fly larvae present feeding on the aphids.
Control: Look for the different predators and parasites such as lady bird beetles, syrphid flies, assassin bugs and parasitic wasps that feed on aphids. This late in the season, control is not necessary.
Bees and Goldenrain Tree (Koelreuteria paniculata)
We received an interesting exchange of emails about bees and goldenrain tree on an entomology listserv list this week.
Juang-Horng ‘JC’ Chong, Ph.D., Clemson University, sent out an interesting inquiry about bees being killed by a golden raintree. Here are his question/observations:
Did anyone ever observe a large number of dead bumblebees associated with goldenrain tree? A good friend, who is also the executive director of a local botanical garden, informed me that the goldenrain tree/Chinese flame tree (Koelreuteria bipinnata) in the garden was in full bloom and killing bees. Last Friday, we counted about 48 dead bumblebees (species not identified) under the tree. At the time, hundreds of honeybees, bumblebees and other native bees were visiting the flowers; only bumblebees were found dead. Ignorant of the effects of goldenrain trees on bees and suspecting that the hive and bees might be poisoned before visiting the flowers, I suggested to my friend to clean up the ground and see what happens next. The ground was cleared on Tuesday.
Dead bumblebees were found on the ground on Tuesday afternoon (20) and Wednesday (42). The trees have never been treated with any insecticides, systemic or otherwise. I have not heard of a similar occurrence. I cannot confirm if something similar is happening in the neighborhood because those may be the only two goldenrain trees within a radius of 10 miles.
David Held, Auburn University, had this response:
What a cool observation. It is possible that the nectar of certain trees may have a narcotic or toxic effect on bees, although the two references that I have don’t include goldenrain tree but Sophora spp. In many instances, the toxic effect can be traced to yeasts associated with the nectar. I would guess that an intoxicated bee that wasn’t poisoned outright would die secondarily from desiccation on a hot summer day.
Here are the bee references for your interest.
P.G. Kevan, D. Eisikowitch, S. Fowle, and K. Thomas. 1988. J. Apic. Res. 27(1): 26-29. P.G. Clinch, T. Palmer-Jones, and I.W. Forster. 1972. N.Z. J Agric Res. 15:194-201. -alkaloids in the nectar inducing a narcotic effect on bees.
Contributors:
Stanton Gill, Extension Specialist, [email protected]
Paula Shrewsbury, Extension Specialist, [email protected]
Ginny Rosenkranz, Extension Educator, [email protected]
Chuck Schuster, Extension Educator, [email protected]
Brian Clark, Extension Educator, [email protected]
Andrew Ristvey, Extension Specialist, [email protected]
David Clement, Plant Pathologist,hgic.umd.edu
Karen Rane, Plant Pathologist, [email protected]
Kate O'Donnell says
Stink Bugs! What works? What doesn’t? We need fact-based information to rid our homes and yard of these pests. All contributors, please chime in. Thanks