Lavae of some kind

Asked July 11, 2015, 6:00 PM EDT

We have these black head, white body larvae coming onto our composite deck. The are coming from between the boards and laying on top of the deck boards. For the past two days I have collected about twenty of them. The fact is that the deck is about 10 feet above the ground. How are they getting there and where are the coming from? What can I do the kill they and make sure that they don't return next years?

Dauphin County Pennsylvania

4 Responses

It looks like a weevil larva to me. Weevils are a type of beetle. Do you have any trees that overhang the deck?

No, we do not have any trees that overhang the house. They come up from between the 1/8 inch space deck boards and somehow just lay on top of the board. The deck is about 10 feet above the ground. So far I have remove about 40 larva in the past several days.

See the attached picture of the deck boards, picture was taken last year.


I am stumped on this one. What is below the deck? Has anything such as bird seed or grain been spilled on the deck?

I was looking at some questions that had previously been sent in regarding insects, and noticed that your hadn't been successfully answered. The insect in your photo is the larval stage of a paper wasp in the genus Polistes. These wasps make the small open comb nests that you might see under the eaves of your house, under your deck or perhaps up in trees. Normally these larvae stick inside the cells in the nest hanging downward. If the nest is damaged or they die during development, they eventually will fall out onto the ground. So I suspect that you have some of these paper wasp nests under the eaves or your house or on a tree limb over the deck area where you are finding these. These larvae are harmless, and the wasps themselves generally don't bother anyone unless the nests themselves are disturbed.