Saturday, July 20, 2013

Pest News for Week of July 22nd


From: Steve Frank, Extension Entomologist

Mimosa Webworms

In Raleigh we are seeing the initial webbing created by mimosa webworms. These are annual pests of mimosa trees which many people including me consider pests in their own right. However, if you are one of the many folks who love mimosa trees sans messy caterpillar webbing then it is time for action. The best way to prevent heavy infestations and extensive webbing is to prune out the nest when they are small (now). Moths overwinter as adults so reducing the abundance of caterpillars in your tree could help reduce infestations next year. Most insecticides available for caterpillar control will also control mimosa webworm, but remember that contact is difficult since they live in water proof bags so rely on stomach poisons for best control.

More information on caterpillars can be found at:


From: Mike Waldvogel, Extension Entomology

Mosquito-borne Diseases

On July 4, I sent an e-mail about the rains increasing some pest problems. Some problems are nuisance pests (such as millipedes), but others such as mosquitoes pose a greater problem particularly with the possibility of diseases such as  Eastern Equine Encephalitis (EEE), LaCrosse Encephalitis, and West Nile Virus. As I suggested in that e-mail, it would be prudent for horse owners to get their animals vaccinated.    

Some of you may have already seen yesterday's reports that Brunswick County had its first confirmed equine fatality from EEE ( 

Despite the name, the disease affects not just horses but people as well. Unlike some other disease-causing viruses of medical importance, you can't get EEE from contact with an infected person or horse.  Mosquitoes become infected when they bite an infected bird and those mosquito species then feed on other birds thus increasing the reservoir of virus in the bird population during the course of the summer. Other mosquito species that bite these same birds act as "bridges" by dining again on horses or people who now become infected.  
Children and the elderly are the biggest concern and so we need to urge our clients to take appropriate protective measures and use insect repellents (see We still recommend the usual measures of emptying rain-filled containers and other objects as well as unclogging gutters, drainage ditches, etc. However, mosquitoes that can transmit EEE will also breed in floodwaters and salt marshes and for that reason personal protection is critical. Many of these mosquitoes are active at dawn and dusk and so altering are activity times can help (but are not a guarantee against mosquito bites). Again, we also urge horse owners to consult with the veterinarian about vaccinating their animals against these mosquito-borne diseases.

I would also add that people with dogs that spend a great deal of time outdoors need to make sure they are keeping up their pet's monthly heartworm medications since some of the same mosquito species that are increasing in numbers can also transmit dog heartworm.  

For more information contact your local Cooperative Extension Center and ask for the Commercial Horticulture Agent.