In two weeks we've lost several large pine branches due to these guys. I would like to know what I can do to get rid of them before they cause more damage. We have a dog and I read that they can cause a lot of damage to dogs and people too, if you touch them.

Any help would be appreciated. Our contact information is for Portland/Tigard.

Thanks, Steve

Reporter
April 13, 2010, 9:24 a.m.

Hi Steve, we're looking into this for you via an expert at the Oregon Department of Agriculture. Is there any chance you have actual photos from your property? Could you get some and post them on this site? The reason I ask is that we do have native tent caterpillars and other species that mimic invasive species - it's always much easier and more reliable if we have a specimen in hand or a photo.

Lisa DeBruyckere
April 13, 2010, 10:01 a.m.

Steve, here's the response from Oregon's taxonomic and survey entomologist:
A photo would be valuable. Specimens in alcohol would be better. Many species of caterpillars are superficially similar to one another. This report almost certainly concerns a native species, the silver-spotted tiger moth, Lophocampa argentata. The larvae feed on many conifers, including pines, sometimes causing substantial defoliation to individual trees. Rarely does this damage extend throughout a stand. The larvae overwinter, so they are large and actively feeding at this time. They make loose webs of silk on the branches they are feeding on. The best treatment is to destroy infested branches or, if a tree is heavily infested, spraying with acephate-containing pesticides or Bacillus thuringiensis (Bt). The hairs of the caterpillars can be irritating (albeit not to the same degree as pine processionary caterpillars, which are not found in North America anyway), so minimizing exposure to webbing and caterpillars is prudent. I've received many reports of this insect this spring.

Lisa DeBruyckere
April 14, 2010, 1:36 a.m.

I've added a photo that was taken this weekend. I hope the photo helps to confirm that this is a native caterpillar, the silver-spotted tiger moth, and not an invasive insect. We have several trees covered with these caterpillars.

Thanks again for your help and assistance. Steve

Reporter
April 27, 2010, 3:32 a.m.

Hi Steve, Jim LaBonte with the Oregon Department of Agriculture reviewed your photo. This is what he said:
"I just reviewed the caterpillar photo. It is a perfect match for the larva of the silver spotted tiger moth. The control measures I recommended earlier would be appropriate for this insect. James LaBonte"

Thanks again for your report! Lisa DeBruyckere, Oregon Invasive Species Council Coordinator

Lisa DeBruyckere
April 28, 2010, 6:40 a.m.