may be active a little earlier this year due to the unusually mild winter season we have been experiencing. Some of the first pests of the year to appear on your plants in the garden and landscaped beds are the eriophyid mite, which likes to dine on hemlocks and white pines, the wooly adelgid which also prefers hemlocks, and Spruce spider mites also become active in March. They favor conifers: arborvitae, firs, spruce, junipers, and pines. By checking your plants early for signs of infestation, you just may save yourself time and money replacing the plant and keeping the infestation from spreading. Look for these three early arrivals now that you are spending a little more time in the garden beds with the weather getting nicer.
March weather can go from one extreme to the other, Cold arctic air and wet rainy weather suddenly becomes warm and sunny. Look for eriophyid mites on hemlocks and on white pines. These very small, wedge-shaped mites are translucent, and/or orange / yellow colored and can do considerable damage to the leaves of hemlocks and pines. The leaves of the Hemlock with turn yellow-green then olive green as the hemlock rust mite feeds upon them.
On white pine, expecially the dwarfs, the mite can be found at the base of the needle. Pull the needles apart to find this small mite. Needles with turn yellow then brown, For both species of tree, heavy infestations may often cause a major needle drop. tap a branch over a white sheet of paper and check for the pest with a magnifying glass. If present in large numbers treat immediately.
Another pest of hemlocks is woolly adelgids. These small, aphid-like insects are covered with a white “wool” which is easily visible. Look for little tufts of cotton on the base on individual needles. The adelgid feeds on the sap of the needle, causing it to turn grey or olive green, and then fall off. Heavy infestations over a few years can kill the tree. New juvenile adelgids, called crawlers, hatch in spring over a long period. Tap an infected branch over a sheet of white paper and with the aid of magnifying glass, check for this crawling stage.
Spruce spider mites also become active this month. They favor conifers: arborvitae, firs, spruce, junipers, and pines. They can be one of the most destructive pests of ornamental conifers. They feed on the underside of needles, causing the yellow, stippled appearance. On hemlock, spruce spider mites can cause the bottom half of needles to turn white. Silky webbing may be present, and needles eventually turn brown and fall off. Use a white sheet of paper and tap on a small branch. These mites will easily be spotted on the paper as red or blackish moving specks.