This caterpillar is sometimes called “orange dog” and is the immature stage of the giant swallowtail butterfly.

Courtesy of Peter Warren

I am finding kissing bugs in my house. Is there any way to prevent them from getting in and biting us?

A: Kissing bugs (aka conenose bugs or assassin bugs) are predator insects that nest with packrats. The first step would be to reduce the packrat habitat near your home. A well-managed landscape is much less likely to harbor rodents. It is difficult to prevent insects from entering your home entirely. Kissing bugs are big enough that you can prevent entry much of the time by making sure all windows and door screens are in good repair and there are no obvious gaps.

We noticed one of our mesquites has tons of hardened sap tubes along the length of the trunk. Does a wood boring insect, or just rapid growth, cause this?

A: Spring is a very active time for sap to be flowing. Sometimes we see sap leaking from branches where there are breaks in the bark from injuries or rapid growth due to good growing conditions. Taking a close look at the area where sap is leaking may reveal cracks in the bark or exit holes from boring insects. Pruning wounds are also a source of sap. Making sure you are properly irrigating and fertilizing your trees can help moderate the growth cracks. In the spring, summer and fall, mesquites should be irrigated every two or three weeks to a depth of 24 to 36 inches. In the winter they do not need irrigation. Keep in mind the absorbing roots are out near the edge of the crown of the tree so place your emitters in that area.

I planted a palo verde tree early this year and I am supporting it with three stakes. How long do I need to leave the stakes up?

A: Tree stakes are a very appropriate for newly planted trees for the first year they are in the ground. After one year remove the stakes and ties to prevent damage where they are attached to the tree. It is important to make sure the trees are not staked too high; half way up is about right. Make sure there is some wiggle room in the ties so the tree can develop its own support; too tight is no good for the tree.

My citrus tree has small caterpillars that look like bird poop eating the leaves. What can I spray to get rid of them?

A: These caterpillars are sometimes referred to as “orange dog” and they are the immature stage of the giant swallowtail butterfly. Mature citrus trees can easily withstand losing a few leaves to these caterpillars so you don’t need to spray anything. Plus, you get the beautiful butterflies if you leave them alone. If you have a large infestation or you simply can’t tolerate them, Bt (Bacillus thuringiensis) is a good organic solution that should be sprayed on the leaves in the spring when the larvae are still young enough to be affected.

Peter Warren is the urban horticulture agent for the Pima County Cooperative Extension at the University of Arizona. He works with landscape professionals, urban farmers and homeowners to promote integrated pest management and best management practices for desert horticulture in southern Arizona. Questions can be sent to .