A. There are no insects that can kill a redbud in this manner (such as the peach tree borer to stone fruit trees). Certain fungi and viruses can kill a tree branch by branch over several seasons, but it would be apparent that this was happening. There are two likely causes for sudden death of a redbud:

1) Water shortage stress - PA had less ran than usual over the past few years with dry summers and little snowfall. One normally does not think about watering trees. The tree gets water from the feeder roots near the drip line (outer edge of the limbs). As the tree grows each year, this circle expands. The problem becomes worse if the circle expands into areas where there are other plants competing for water such as other trees or shrubs. This would be the case particularly with evergreens, which need water in the winter as well. Leaves would brown at the edges and drop which may have been overlooked if it happened in the fall, even if it was earlier than normal.

2) Verticillium Wilt - the chief cause of sudden death in many species of trees including redbud. It is a soilborne fungi that occurs randomly, perhaps in one square foot of your yard and nowhere else in the neighborhood. It should be considered permanent and untreatable. The fungi enters the tree through feeder roots when they grow into the infested soil or where a root may be damaged and quickly moves through the sapwood. Behavior is unpredictable. It often kills one branch or, as in your case, the whole tree quickly when it enters several roots. The disease often shows it's presence by a brown ring within a cross-section of the root or branch, but a diagnosis is only certain with a lab test.

When you dig up the tree, collect several root and branch sections from around the tree that are bigger than your thumb and around six inches long. Send them to:

The Department of Plant Pathology
Buckhout Laboratory
University Park, PA 16802

Explain the problem and tell them when the samples were cut. If the results are positive, do not replant a redbud tree. There are other trees that resist verticillium wilt such as crabapple tress and Bradford pears. (Kent S)

Q. I have petunias and other flowers that have potato bugs on them. They seem to be killing my flowers. What should I do?

A. Colorado Potato Beetles overwinter as an adult in the soil. These adults typically emerge in early May, find a host plant, and begin to feed and mate. Eggs are laid in early to late June and take about a week to hatch. The larvae feed for 2-3 weeks before dropping from the plant and burrowing into the gound to pupate. A second generation of adults emerge about a week later to begin the cycle all over again.

The recommended method for control in home landscapes is to handpick the adult beetles from the affected plants. The beetles can be dropped into a container of soapy water and discarded with the trash. Watch for bright orange-yellow egg clusters on the underside of leaves from early to late June and either smear them or discard the affected leaves. Also, watch for a second generation of adults in late July to early August. Using a deep layer of straw mulch has been noted to reduce infestation. Lastly, avoid planting petunias and other susceptible plants in the same spots year after year. Rotating the types of plants will help reduce infestation.

It is possible to use insecticides, but Colorado potato beetle possesses the ability to rapidly develop resistance. Rotating the use of different classes of insecticides helps. If you are interested in using insecticides, I can get information on recommended products. (Sue B)