US National Arboretum


Pest Management

Pest Management Tips: November

image of a ladybug  image ofvolutella stem blight on boxwood November is an excellent time to look over your landscape trees and shrubs and perform any necessary pruning chores. Remove any limb that crosses or rubs on another. Thin out areas that have gotten particularly dense; this will lessen the likelihood of disease development due to increased air flow, and allow for faster drying of moisture. Shrubs pruned as hedges can be particularly susceptible to stem and leaf diseases. Volutella stem blight on boxwood, usually seen as large areas of dead, straw colored leaves, can be discouraged by selective pruning this time of the year. Branch thinning, instead of foliage shearing, will improve air circulation and discourage the spread of this disease.

image of a ladybug   image of dead branches on azalea caused by botryosphaeria Generally, remove any dying or dead limbs, which can shelter insects and diseases. Brown branches on pines could be caused by tip moths or diplodia tip blight fungus. Removal of these infected branches will lessen the severity of the pest the following spring. Likewise, removing dead branches on azaleas and other ornamentals, caused by botryosphaeria, limits the spread of this disease. Dead branches due to a fireblight infection must also be removed. All cuts should be made several inches below the infected area, and pruning tools should be disinfected between pruning cuts. Research has shown that a 10% bleach solution (1 oz. household bleach in 9 oz. water) is the most effective disinfectant for fireblight and other pathogens. Remove any plant sap and debris from tools before disinfecting. A quick dip between cuts will suffice. Be careful with this solution, as it can damage clothing. Undiluted alcohol can also be effective, but tools must be soaked at least one minute for good results. It is suggested to use two or more pruners and let them soak in the alcohol between uses. Always clean, rinse, and oil metal pruning equipment when finished with pruning chores.

image of a ladybug   Asian ladybird beetles, Harmonia axyridis, can be annoying this time of year, as they seek a protected spot to spend the winter. They sometimes find their way inside and can congregate in large numbers. Ladybird beetles are beneficial insects, however; they consume aphids and other pests. If these beetles discover hiding places in your home, put a new bag in your vacuum cleaner, vacuum them up, and release them outside.

image of a ladybug    Other insects may find their way inside your home this time of year as they seek refuge from winter’s cold. To prevent boxelder bugs and others from entering your home, check your windows and doors for small openings. Caulk around leaky windows and place screens over attic and other vents.

image of a ladybug    image of ganoderma butt rotAutumn is a good time to look for fruiting structures of fungi that attack, weaken, and eventually kill ornamental trees. There are many types of fruiting structures, but they indicate that the tree may become a hazard. The fungal infection produces decay-causing enzymes, seriously weakening the wooden structure. One such disease, Ganoderma butt rot, has a shelf-like fruiting structure, which looks much like a pizza pie. Millions of spores are formed on the white underside of this shelf. When scratched, this underside turns brown and has the common name, “Artist’s Conk.” Infected trees may take several years to die, but this disease makes the tree very susceptible to toppling in a wind storm.

image of a ladybug    Adding fallen leaves to your compost pile is a great idea and is far easier than trying to bag up or cart off a large amount of leaves. Adding an organic fertilizer as a nitrogen source will hasten decomposition. Turn your pile once in a while to aerate. A properly decomposing pile will warm up to over 140 degrees Fahrenheit and effectively kill insects, diseases, and weed seeds that may be present. Next spring, you will be rewarded with leaf mold, an excellent soil amendment or mulching material.

Pest Management Tips Home

The best way to manage pests is to use a combination of chemical and non-chemical control. Only take action when the problem is serious enough to damage the plant. If we all use Integrated Pest Management (IPM), we can control pests in an environmentally conscious manner.

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Last Updated   June 11, 2009 2:54 PM

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