At the U.S. National Arboretum we manage our pests with a
program called Integrated Pest Management (IPM).  IPM means
using a combination of methods to control and prevent pests.  Here
are some tips with a variety of control methods to help you start
your own IPM program.
 

    Check your pines for brown tips or die back. This can be caused by Nantucket pine tip moth larva. The caterpillar burrows into the terminal, causing the growing tip to die. This insect winters in the terminal, so removing the tips will reduce this year’s population. A second generation also occurs in June, so removing dead tips through spring will help control this pest.

    It’s still not too late to add compost to your vegetable garden pot. Adding organic matter increases drainage and water retention and also makes nutrients available for your summer vegetables.

    Watch for eriophyid mites on hemlock and white pines (especially dwarf cultivars). These extremely small, wedge-shaped mites are a translucent, straw, or orangey-yellow color. They can do considerable damage to the leaves of hemlock and pine. Hemlock leaves will turn yellow-green then olive green. For both hemlock and pine, heavy infestations will cause major needle drop. Tap a branch over a white sheet of paper. Check for this pest on the paper with a strong magnifying glass (20x). If present in large numbers, treat infected plants with a 2% horticultural spray.

    Another pest of hemlocks is woolly adelgids. These small, aphid-like insects are covered with a white “wool” which is quite 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 March and April. Tap an infected branch over a sheet of white paper and with the aid of magnifying glass, check for this crawling stage. A 2% horticultural oil spray or insecticidal soap will control crawlers.

    Don’t let those little weed seedlings grow into big, nasty, hard-to-control weeds. Seedlings can be easily pulled out or removed with a hoe. Don’t procrastinate until the weeds are too large to pull or have set an abundant crop of weed seeds.

    Spruce spider mites are a major pest of conifers in many parts of the country. They attack spruce, hemlocks, junipers, arborvitae, cryptomeria, and many other species. If you own Dwarf Alberta Spruce, you most likely will have spruce mites at some time. They are most active in the cooler months of spring and again in the fall. A complete generation can occur in about two and a half weeks, so the population can rapidly build. Feeding on the needles, they cause the needles to have a gray or stippled appearance. Young plants with heavy infestations can die; older plants can die after repeated attacks. Spruce mites are larger than eriophyid mites, so when you tap an infected branch over white paper, black specks are visible. After tapping, if you see more than 20 mites, treat with horticultural oil.

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.