I have heard there are 2 types of tent caterpillar. one harmful one not harmful how do we tell them apart? thanks
Have a look at this I think it gives all the information you need. Tent Caterpillars - NYS Dept. of Environmental Conservation
Do you have photos of your current concern (close-up and far away showing plant (shrub/tree) being chewed)
@anon125 yes it is a long read, but it gives you the photos to ID. For me your pictures show an infestation and defoliation, but not a positive identification. At this time of the year the damage is cosmetic at the moment, but I see a few more nests, this can cause almost total loss of leaves to a tree very quickly. But again, I am not convinced that this is new. There are arborist's / tree surgeons that will climb trees and remove and destroy these nests, so this is something to be considered. Far too dangerous to do yourself, if you don't have the equipment or experience. Others may have better ideas.
I don't think it is that important to know the specific identity of the tent caterpillars we are seeing quite frequently these days in the Oceanside area. There are definitely more this year than last. When you've lived long enough on the BC Lower Mainland or here on the Island, you will have observed that tent caterpillar infestations go in cycles. (I remember one particularly bad year when my sister lived on Galiano Island in a cottage surrounded by alders being kept awake at night by the sound of thousands of caterpillars munching on thousands of leaves.) The one consolation is that they seldom, if ever, actually kill the trees they feed on. Here is an excerpt from a Wikipedia article that talks about tent caterpillar cycles: Tent caterpillars exhibit boom-or-bust population dynamics. The most notorious of the outbreak species is the forest tent caterpillar. During outbreaks, the caterpillars can become so abundant that they are capable of completely defoliating tens of thousands of acres of forest. Even though these outbreaks do not follow true cycles in the sense that they occur at regular intervals, some particularly prone regions have recorded outbreaks every ten years or so. Caterpillars rarely remain in outbreak numbers for more than two to three years. Factors which bring outbreaks to a close include parasitoids and disease. In some cases populations collapse because caterpillars starve to death either because trees are completely defoliated before the caterpillars are fully grown or because the quality of host leaves declines to the point where they are no longer palatable. Defoliated trees typically refoliate after caterpillar attacks and experience no lasting damage. In some cases, however, trees or parts of trees may be killed after several seasons of repeated defoliation.
we will call a professional tree trimmer to remove it, maybe without lopping branches. thanks everyone for your kind help
When did the tent caterpillar houses become visible? It looks like they are working for the power utility line company — keeping the tree out of the wires :)