We’ve learned through the IPM Research Group that by the time we actually see harmful insects or the havoc wreaked by diseases, it is difficult tocontrol the pest, In order to be most effective and to minimize the amount of control substance needed, we prefer to nip pest problems “in the bud”we time our control applications based on predictable cycles of nature and on the habits of the pests in the past-before they get out of hand. For example, we’ve learned that an application of dormant oil in March is the best treatment for controlling the hemlock woolly adelgid – before the eggs can hatch! (This is also true of mites, aphids, and scale insects.) However, the white cottony sacs that appear at the base of hemlock needles can be treated in late June through July and also in September through October, but those treatments can be more risky to beneficial predators.

Another insect known as elongate hemlock scale frequently appears on samples of hemlock that customers bring to us; we also observe it when monitoring customers’ properties. This insect causes hemlock trees to lose needles and can eventually kill them. Although many customers are willing to prune out webs of tent caterpillars and webworms themselves, they prefer to have us take care of the adelgids and scales on their hemlocks. We use horticultural oils and soaps to control them.

Two examples of problematic diseases are dogwood anthracnose and crabapple scab. These diseases affect dogwoods and flowering crabapples, respectively, as the trees leaf out, but this is several weeks after the ideal time to control the disease. Usually the treatments begin when the leaf bud breaks and continues for every two to three weeks throughout spring.

Each year Gary’s Tree & Shrubbery Service mails proposals to our customers for tree and shrub care applications for the upcoming year. Many of these suggestions are based on evidence of pests during the previous year. An early response to this proposal allows us to order supplies and plan our work schedule efficiently. It also reassures you that we will be out to take care of your trees and shrubs before pests get the better of your plants.