Spring has sprung and with it come some tiny bugs that cause problems. The Eastern tent caterpillar has been active on flowering crabapple trees and the Sandhill plum. Not to be outdone, the European pine sawfly is present. It likes to eat Mugo pines. It will also feast on Scotch, Austrian, ponderosa, Virginia and eastern white pine.
Neither bug will kill the tree on which it has started to feed. Tent caterpillars create a web-like home in your trees; they will complete their feeding in mid-May. If you plan to remove the tent, the best time is during naptime between mid-morning and mid-afternoon. If you remove the tent any other time, foraging caterpillars will be out feeding and not inside the tent. You will have only made them homeless and mad. They will continue to eat your tree.
Don't prune the tree where the tent is attached -- this will only leave a hole in the canopy. After the tent caterpillars have finished feeding and have moved back into the debris and soil around your tree, the tree will put on new leaves in two to three weeks.
If you want to eradicate tent caterpillars you can use an insecticidal spray of Dursban or Sevin. Spray the area around where the caterpillars have been feeding, as this will be their next area to attack. It is not necessary to spray the entire tree.
European pine sawflies may not kill your tree either, but they will eat the pine needles and, unlike leaves, once the needles are gone, they are gone for good. The sawflies feed on old needles and heavily infested trees will have a "poodle-look"-- poofy terminal growth at the end of the branches, while the branch itself is needleless.
The needles around infested terminals will look light and withered and will stand out in stark contrast to normal healthy green terminals. Infested terminals can be selectively pruned out or you can try to control the sawflies using insecticides like Dursban or Sevin.
--The Garden Calendar is sponsored by K-State Research and Extension-Douglas County and written this week by Master Gardener Bill Padgett. For more information call the Master Gardener Hotline, 843-7058, from 1 p.m. to 4 p.m., Monday through Friday.