The rainy, cool conditions that characterized the 2014 growing season have left their mark on several trees and shrubs. There is an unprecedented amount of foliar diseases in the landscape, some of which we don’t commonly see from year to year. Much of the disease organisms can be found in/on foliage that has dropped to the ground, waiting for next spring when they can infect new foliage again if the conditions are right. So, anything you can do to rake/blow/remove/mow fallen leaves away from affected plants can significantly reduce the incidence of disease next year.
Leafblowers are great for blowing dropped foliage and cuttings out of container production areas and are used routinely for IPM before plants are consolidated and cold frames covered with poly.
There was a lot of spruce spider mite (Oligonychus ununguis) injury this year, probably due to the fact that it was so cool and rainy, their favorite conditions. Spruce spider mites will feed on conifer foliage late into the fall and believe it not, a lot of injury can happen in the months leading up to Christmas. Adult spruce spider mites are tan brown and black with 8 legs, nymphs are smaller and paler while the tiny spherical eggs are red and cling tightly to foliage. We can find all life stages at this time. Monitor lower branches, this is where most of the feeding damage is done, on the east side of the tree. Shake branches vigorously over a sheet of white paper (on a clip board) and count mites to assess populations. More than 5-10 mites per branch test may indicated significantly damaging populations.
Several miticides are registered for spruce spider mite in the nursery (Floramite, Kanemite, Shuttle). Insecticidal soap and horticultural oil is registered for spruce spider mites in the landscape. Good coverage on inner canopy is vital to management of mites. Place water sensitive paper inside the canopy, where the mites are, and assess the cards for good coverage after spraying.