Pest Management Tips: February
Unfortunately, the extended period of warm weather early last month, coupled with long periods of very cold temperatures, will cause some disappointment this summer. Some summer flowering shrubs will not flower as expected because their flower buds have been killed by low temperatures. Bigleaf hydrangea plants broke dormancy during the warm spell and their leaves began to unfurl from terminal buds. Flower buds, which formed early last fall, are susceptible to freezing once growth begins. Many buds froze completely late last month, so it is expected there will be many fewer flowers this summer. Side buds will grow and new leaves will be produced, but no flowers, unless you happen to grow the newer, reblooming types that produce flower buds on new growth.
Did you have problems with caterpillars feeding on your trees and shrubs last year? February is a good time to look for egg cases and destroy them before the eggs hatch in the spring. Tent caterpillars produce a ¾ to 1 ½ inch black egg mass containing several hundred eggs. They are deposited on twigs and small branches of apples, oaks, maples and many others. Pick these off and destroy them. Gypsy moth deposit egg masses on any flat surface. These egg masses are about 1 ½ inches long and covered with short orangey-yellow felt-like hairs. They can contain 600 – 1000 eggs, so the removal of even one mass can impact your landscape. Look for them on the bark of trees, branches, signs, sides of garages, and even patio furniture.
It will soon be time to start seeds indoors for your summer garden. Oftentimes, seedlings can be lost to a variety of damping off diseases. These fungal diseases cause seeds to rot away before they germinate or seedlings to collapse at the soil line and die. These diseases are hard to control once infection has begun, so prevention is the best strategy. Avoid using contaminated soil or containers and always use new, clean pots when starting seeds. Never use garden soil in your seeding mix, but instead look for bags of potting soil that are specifically designed for sowing seeds or mixes have been pasteurized. These mixes may say “steam sterilized” on the label, indicating the mix has been heated to 160 degrees F to kill any disease organism that may be present. Many professional growers will treat their seedling flats with a beneficial fungus, Trichoderma harzianum, which protects seedlings from damping off diseases. Trichoderma will colonize roots, making them stronger, and parasitize other fungi, including the damping off diseases. Look for this organic fungicide active ingredient, Trichoderma harzianum, in garden centers. It is mixed with water and applied to the soil.
Winter is a great time to reduce the bagworm population, decreasing damage next summer. Eggs of the bagworm moth survive the winter in bags left on the tree. These bag, which are 1 to 3 inches long and hang from the branches, are easy to spot, especially on deciduous trees including bald cypress. Check your evergreen conifers as well. Pick off the bags and throw them away. Each bag contains 500 to 1000 eggs, so removing even a few can significantly lessen the injury next year.
Forced air heat during winter resulting in very low indoor humidity can cause houseplants to suffer. Do not allow them to dry out, as they will be more susceptible to mite damage. These pests suck sap from leaves, which destroys the chlorophyll, resulting in yellow, stippled leaves. Heavy populations form silky webbing on the undersides of the leaves. Under favorable conditions, one generation time is only a couple of weeks, so populations can increase rapidly. Check for mites by holding a white sheet of paper underneath a branch and tap on the branch. Small, specks, the size of a period, will appear on the paper and begin to crawl around. A good spray of water will reduce a mite population. This shower will also reduce the dust accumulation on the leaves, which in turn, will increase photosynthesis.
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.
Last Updated June 11, 2009 3:01 PM
URL = http://www.usna.usda.gov/Gardens/pestmgmt/IPM_2008-02.html