With a few days of some warmer temperatures the past couple of weeks, you may be thinking about your landscape and trees. How did your coniferous trees make it through the winter? If you have trees that have been damaged by wind or or they are just over grown, it would be wise to prune them if you haven’t already. If you have had problems with your trees in the past with insects and/or diseases, it is important to evaluate them this spring to see if they look healthy.
The last few years have been very hard on a number of coniferous trees. Dry and hot weather and sometimes the addition of other disease and insect problems put a lot of stress on the trees and some didn’t survive. The variability in temperatures and rapid drop to cold temperatures can damage some trees, plus the combination of cold temperatures and strong winds have also taken their toll on some smaller coniferous trees. If you have not yet checked your trees out this spring, you should check evergreens for off color or dried and brown spots. Sometimes through the winter evergreens, especially different types of shrubs will get some winter burn and will need to be pruned. Spruce trees can also be affected by insects, such as the spruce spider mite or the disease Rhizosphaera needle cast. I have had a number of calls over the years about these spruce tree issues. In recent years, the disease Sirococcus shoot blight has been showing up in some younger spruce trees in the area. Keep a close eye on young trees this spring and keep them watered to reduce stress on them. Treatment with a pesticide may be warranted for control of these insects or diseases. A couple of pine tree diseases that are common in the area are Dothistroma needle blight and Sphaeropsis tip blight. Both of these diseases have been identified in the area and unlike pine wilt, these diseases can be controlled with fungicides.
I mentioned the spruce spider mite earlier, but the two spotted spider mite has been causing problems here on evergreens and ornamentals for several years. Symptoms of this pest usually show up in summer when it is hot. If the infestation is severe, insecticidal soap or horticultural oil may be used for control. These are just a few of potential tree pests we need to be aware of in coniferous trees. We have a guide that provides control measures for several pests and also individual guides that discuss specific control of pests. If you have further questions on tree problems, feel free to contact your local extension office or me, Gary Lesoing at University of Nebraska Extension in Nemaha County at the courthouse at 1824 ‘N’ St. in Auburn (402) 274-4755, (402) 274-9639 (cell) or email firstname.lastname@example.org.