Ornamental Crops IPM E-newsletter, 2010
For Summer 2010
Program Status: The NYS IPM program is still active. Although the program was funded at a reduced level by the state, we are still able to provide research and education for IPM in ornamental crops. We thank all of you who expressed concern and took time to write letters in support of our program. For more information on our program and the funding status, see this letter from our Program Director.
In this Issue:
- Balsam Woolly Adelgid: A tiny, but damaging insect
- Fall is Lady Beetle Season: Too much of a good thing
- Greenhouse IPM “In-Depth” Hands-On Workshops
Elizabeth Lamb, NYS IPM Program
The balsam woolly adelgid (Adelges piceae) is a small (less than 1mm) aphid-like insect that feeds on true firs (Abies species). Fraser, noble, and balsam firs are particularly sensitive to attack. It is one of the few insect pests that will actually kill the trees and even low populations can make trees unsaleable.
At low populations, the insects can be difficult to detect. An early sign of damage on some trees are swellings near the ends of twigs at the bud and branch nodes. The balsam woolly adelgid has sucking mouthparts that are inserted through the bark to feed and through which they inject a chemical that promotes plant growth. The excess growth produces the swellings, called ‘gouting’, which can result in stunted needle and twig growth as the vascular tissue is restricted. Trees may develop a characteristic crooked top. In other cases, the adults feed along the main trunk in large numbers, causing the trunk to appear white with the waxy ‘wool’ created by the adult adelgids and resulting in damage to the sapwood. Infested trees may seem stiff when rocked back and forth because of the insect’s effect on the wood. The changes in the sapwood also restrict the flow of water and nutrients throughout the tree, leading to tree death. Balsam woolly adelgid often attacks larger trees first, although any size can be infested.
The adults, all female, are not mobile but form a white woolly covering under which they feed and lay eggs, up to 200 eggs each. When the crawler stage hatches from the egg, it leaves the covering and moves around the tree to find a suitable feeding site. Once established in a feeding site, the crawler changes through the nymphal stages to become an adult, and produces the white wax threads that form the woolly covering. Crawlers can be blown or carried from tree to tree, the primary method of dispersal. There are usually 2 generations per year in the Northeastern US. The overwintering stage is the first instar nymph or crawler.
Reducing stress on trees through proper site choice and fertilization can reduce damage to trees. Balsam woolly adelgid numbers increase when trees are overfertilized with nitrogen, like other adlegid and aphid pests. There are several predatory insects that feed on the balsam woolly adelgid, primarily generalist feeders like ladybugs. They are unlikely to be able to control a large population of the adelgids. Very cold temperatures (-15 to -30 F) can reduce the population but will not eliminate it. Scout in spring for twig swelling and misshapen leaders and in summer and fall for the cottony wax covered adults. Removing infested plants is essential to control balsam woolly adelgid in a Christmas tree plantation. When removing trees, cover them to prevent spreading the adelgid. Spot spray the trees around those removed. Chemical control must be used at the crawler stage, near budbreak, because the waxy covering makes treatment of adults difficult.
Sources for this article:
Balsam woolly adelgid, 2006, I.R. Ragenovich and R. G. Mitchell, Forest Insect and Disease
Leaflet 118, USDA Forest Service
Insects that Feed on Trees and Shrubs, 2nd Edition, 1991, W.T. Johnson and H.H. Lyon, Cornell
University, pp 74-75
Balsam woolly adelgid, a pest of true fir species, 1992, A. Antonelli, Washington State
Brian Eshenaur, NYS IPM Program
Lady beetles in the house have become a part of autumn for many homeowners. The Asian, or multicolored, lady beetle (Harmonia axridis) is currently the predominate lady beetle species in the US. The cooler temperatures of autumn trigger these lady beetles to seek a place to spend the winter. In their native lands of Japan and China they would gather in crevices of rock cliffs and outcroppings. In North American, homes are often where they try to spend the winter. Gathered around a windowsill or in a group between the wall and ceiling they may all look the same but with a closer view, variation is evident. The Asian lady beetles’ color ranges from pale yellowish orange to bright red. They may have up to 20 black spots on their backs or may have none.
All lady beetles are beneficial insects and Asian lady beetles are such voracious feeders of aphids and other soft bodied pests that they were released for biocontrol many times in North America beginning in 1916. These lady beetles are born hungry; the average larval lady beetle consumes a total of 230 aphids from egg-hatch to becoming an adult beetle about 20 days later. As adults they continue to feed, consuming about 40 aphids a day during the growing season and some of these ladybeetles may live up to 3 years. Their pest consumption rate has been a benefit in reducing aphid and other pest insect populations. They are known to control pests of apple, pecan, citrus, pine, soybean, alfalfa, cotton, and winter wheat. By 1988 they were found to be established in the southern US, and from there they have quickly spread throughout the US.
Now their high populations are causing some problems. They sometimes feed on ripening fruit crops such as apples, peaches, raspberries and grapes. It is a particular problem for the wine industry when the Asian lady beetles are in the clusters and are harvested and crushed with the grapes, imparting an off-taste to the wine.
Even though they may be keeping pests in check over the summer, come fall their presence in homes can be a nuisance and can even trigger allergic reactions in some people. Also in the annoyance category they will sometimes bite and try to feed on the skin. Nature, being what it is, always seeking a balance, the high populations of the Asian lady beetle have not been ignored as a food source. There’s emerging research examining several natural enemies as controls of Asian lady beetles, which include parasitic wasps, flies, fungi, a nematode, a mite and even birds.
Control in the home:
Prevention is key and good control starts outside the home by blocking the beetles’ entry by sealing gaps and cracks around windows, doors, siding and utility pipes with caulk. Similarly, make sure widow screens are in good repair.
If beetles become a serious nuisance within a dwelling, remove and dispose of them using a broom and dustpan or vacuum cleaner. When using a broom and dustpan, gently collect the beetles to avoid alarming them. If alarmed, they may discharge a yellow fluid that can stain walls, and fabrics.
The use of insecticides for controlling populations indoors is not recommended.
Asian ladybugs (Harmonia axyridis): A new seasonal
indoor allergen Allergy and Clinical Immunology Volume 119,
Issue 2, Pages 421-427 (February 2007)
The New York State Integrated Pest Management Program will sponsor “IPM In-depth” workshops this fall at various locations throughout the state. Participants in these workshops will get hands-on experience in 3 topics: production methods, insects, and plant diseases. For information on specific topics, please contact the County Extension Educator listed below. Pending DEC approval, 2.5 pesticide recertification credits will be available.
Dates, locations and contact information for IPM In-Depth programs:
September 9 – Albany County, Chuck Schmitt - email@example.com. 518-765-3500
September 10 – Suffolk County, Nora Catlin - firstname.lastname@example.org, 631-727-7850 ext. 214
September 30 – Niagara County, John Farfaglia - email@example.com, 716-433-2651 x226
October 1 – Wyoming County, Lutie Batt - firstname.lastname@example.org, 585-786-2251
October 15 – Delaware County, Janet Aldrich -jla14@cornell edu, 607-865-6531
October 29 – Dutchess County, Stephanie Mallozzi - email@example.com, 845-677-8223 ext. 104
Questions? Contact Betsy Lamb at 607-254-8800 or firstname.lastname@example.org