Post-Harvest Pests on Christmas Trees: Control on the Retail Lot

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Post-Harvest Pests on Christmas Trees:
Control on the Retail Lot

Do's and Don'ts

The following are some simple steps you can take to reduce the chances of selling a tree with post-harvest pests

GET EDUCATED: Know what these pests look like so you can recognize them. The best source of information is the North Carolina State web site found at: http://www.ces.ncsu.edu/fletcher/ programs/xmas/postharvestpests/.

CLEAN UP: One concern the public has with real trees is their messiness. Shaking or rinsing trees off with water before displaying them will reduce the number of dead needles, leaves, and pollen on trees. It will also shake or wash pests off. If you see insects such as Cinara aphids falling out of a tree, set it aside for more thorough inspection and treatment.

TREAT IF NECESSARY: Most post-harvest pests are easy to control. A thorough job of washing off the tree with water may be enough. Insecticidal soap is the safest material to spray if washing doesn’t get the job done. Insecticides labeled for spraying in the home for household insect control such as bifenthrin or permethrin (look at the list of active ingredients on the label) will also control these pests while being safe to use.

HAVE INFORMATION AVAILABLE: The website includes a handout for homeowners regarding these pests. (See link below.) You can download, print, and keep a copy on hand for any customers who have questions. Make sure everyone on your staff knows where to find the handout if pest issues come up.

KEEP THE GROWER INFORMED: If you do find post-harvest pests, let the grower know so that steps can be taken to control other pests.

Christmas trees in North Carolina are grown in a near-natural setting. Most tree patches are adjacent to woods. Native broad leaf plants and grasses serve as ground covers around trees. There is an abundance of wildlife, such as deer, turkey and songbirds. There is also an abundance of insect activity as butterflies, pollinators and natural predators like lady beetles and praying mantids find a place to live and thrive.

Unwanted Hitchhikers

Christmas trees provide a well-protected place for insects to live through the cold and snow of winter. When you bring the tree into the home or even to the warmer climates of a southern retail lot, the insects think spring has come and become active again, even starting to reproduce. There are several kinds of insects that spend the winter in conifers such as Fraser fir. Fortunately, with Christmas trees, these unwanted hitchhikers do not bite or cause disease. Like ants at a picnic, they are just a nuisance. In many ways these hitchhikers are a symptom of a fresh tree recently harvested. Post harvest pests on Christmas trees can include Cinara aphids, spider mites, and praying mantids.

Rarely Occur

Most years, these pests are rare. Perhaps one tree in 100,000 has any one of these pests on it. North Carolina Christmas tree growers are addressing this issue as it arises. In a survey conducted in 2006, less than 10% of Fraser fir growers reported seeing Cinara aphids, the most common post-harvest pest. These pests are more common when the weather is still warm at harvest. Growers are increasingly scouting in the fall and treating for these pests in August or September if they find them. But no pesticide treatment is 100% effective. It only takes a few live individuals surviving on the tree for these pests to end up in the home where they will continue to reproduce.

Not the Grower's Fault

Should the growers have treated for these pests? Unfortunately, they didn't even know they were there or they would have. Sometimes it's a little like trying to find a needle in a haystack. When enough trees are infested with pests, they can be found through scouting and treated. But sometimes only one tree in more than an acre of trees has one of these post-harvest pests on it. No one notices they are in the tree until they are brought to the tree lot. In many ways, these hitchhikers are a symptom of a fresh tree recently harvested. If the tree wasn’t fresh, they wouldn’t be there.

Don’t get bugged by unwanted pests! Take the necessary steps to insure that your customers will enjoy the Christmas they deserve with a fresh, pest-free tree.

Rogues' Gallery of Post-Harvest Pests

For More information

Recommendations for the use of agricultural chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention or listing of commercial products or services in this publication does not imply endorsement by North Carolina Cooperative Extension nor discrimination against similar products or services not mentioned. Individuals who use agricultural chemicals are responsible for ensuring that the intended use complies with current regulations and conforms to the product label. Be sure to obtain current information about usage regulations and examine a current product label before applying any chemical. For assistance, contact your county Cooperative Extension agent.

Prepared by Jill Sidebottom and Jeff Owen
Area Christmas Tree Specialists
NCSU College of Natural Resources
NC Cooperative Extension Service

North Carolina Christmas Trees