I hope everyone is recovering from Sandy. As we start to leave fall and head into winter you may think your tree and shrub pest problems are over – well, think again! Yes, it’s true that most insect and disease problems are long gone by the time November and December roll around, but not all. Some problems are just getting started and for other conditions winter is the best time to treat them.
Scale insects can be a treated in the fall and winter. Many species of scale insects overwinter under a waxy coating for self-protection. They do not move during this stage in their lifestyle, but many will continue to feed if temperatures remain warm enough.
Spider Mites can also be a problem in the fall and winter. Some species are actually more active in colder weather – and these are usually referred to as cool season mites. Eriophyid mites and the Spruce Spider Mite both fall into this category. You should check all needle bearing plants, especially spruce and pine, for the presence of spider mites. Warm days – over 45 degrees following a period of cold weather is enough to “wake up” these pests and cause them to start feeding. This can often happen on plants near reflected heat and sun such as along roadways, at the corners of buildings and near windows.
The Hemlock Wooly Adelgid is another insect pest that will do damage during the winter. As with the above pests, late fall treatments and warm day inspections are the best approach.
Spend some time this fall with an Arborist and go look at your trees and make a plan for their health.