The Seven-Year Pest Control Battle for Christmas Tree Crops

A robust pest management plan leads to a valuable Christmas tree crop.

You’ve got to be tough to be a Christmas tree!

According to the Agricultural Marketing Resource Center, a self-described, “national information resource for value-added agriculture,” somewhere between one-quarter and one-half of all Christmas trees planted for the market don’t survive the seven or so year journey between the planting and sale of the tree. For those seven years, a Christmas tree is beset by an astonishing array of pests with insects, vertebrates, disease and weeds each vying for a “share” of the crop with weather often lending a helping hand to each. All that being the case, it’s obvious how important it can be to the bottom line of a Christmas tree farm, whether it be a large plantation or a “mom and pop” operation, to do everything possible to reduce tree loss and enhance tree quality and quantity for the seven years between planting and harvest.

It’s about the IPM

Discussing just how important pest control really is when it comes to Christmas tree operations, Sarah Pickel, Integrated Pest Management (IPM) education specialist at the Pennsylvania Department of Agriculture and author of the department’s Christmas Tree Scouting Report comments, “For a crop that will be in the field for typically 7-plus years, pest problems are almost a guarantee and often those trees will face multiple pests in their life span. Some of those pests have the potential to negatively impact a tree’s aesthetics to the point of rendering it unsalable. If a grower is going to invest in this long term crop, they should be doing all they can to ensure its success. Even though becoming familiar with the large amount of pests affecting Christmas trees in the northeast can be time consuming, the value of being able to successfully combat each of those pests can’t be overstated.”

In recent decades, for growers across the agricultural sector, IPM has become the go-to process for enhancing not only production but, marketability. Much of Pickel’s professional life is spent working to help tree farmers — not only in Pennsylvania but throughout the Northeast — learn how to combat the multitude of pests threatening their Christmas trees and then put that learning to work on the ground to enhance productivity and marketability through IPM. Reflecting the importance of its position as the fourth largest cut Christmas tree producer in the nation, the Commonwealth has become a leader in Christmas tree research focused on IPM, then sharing findings with tree growers throughout the Northeast.

In its broadest application, IPM is an information based strategy aimed at controlling agricultural pests based on on-going monitoring of threats, on-going adjustment to treatment protocols in reaction to the results of that monitoring, the weighing of costs against benefits, minimization of risk to both the crop and to the larger environment of the growing operation, environmental enhancements where possible, and other factors to arrive at a balanced set of actions designed to ultimately optimize the productivity of an agricultural enterprise.

Paralysis by analysis

Because an IPM program can require a considerable effort gathering information, collating that information and acting on the results, some growers, especially those with smaller operations, can sometimes be intimidated by the seeming difficulty of bringing an IPM program to fruition.

On the other hand, as one mid-west expert on IPM has commented, “Farmers don’t become successful just by buying land and equipment. Being a farmer is a full time job, even when nothing is growing. To be successful, farmers must be continuously upgrading their knowledge of all aspects of their business, including IPM.”

According to Pickel, even the holders of very small acreages should not be intimidated by IPM. In the Northeast especially, thanks to collaboration between Pennsylvania’s Department of Agriculture and Penn State University, as well as similar efforts in New York at Cornell University and elsewhere, a wealth of easily accessible knowledge about Christmas trees and the pests that plague them is readily available. “Using IPM on any scale of farm will save growers money and time by allowing them to use small scale pest control options before problems get out of control,” Sarah puts forward. “When larger scale pest control actions are necessary, IPM can allow growers to limit pesticide by targeting precise life stages with one or two appropriately timed applications instead of just hoping that a pest will be controlled with multiple applications over a broader time frame. This savings on pesticide expense and application time is worthwhile to any grower, no matter the size of the farm. ”

“If a grower is overwhelmed by starting to use IPM,” Pickel continues, “I’d recommend changing practices for just one pest. A good option is the white pine weevil, a pest with great damage potential. By setting a simple emergence trap, growers can easily determine when this beetle active in the trees in spring. With one appropriately timed pesticide application, a grower can prevent the damage. After seeing the benefits from this IPM technique, growers will be more likely to branch out into a more complete scouting (scouting involves examination of the crop to determine the kind of pest present as well as the extent of any infestation) program. In Pennsylvania, more farms fall into the 1-2 acre size category than are in any other size category. That means there are a lot of small farms in operation out there and IPM could be useful to all of them.”

Reaping the rewards

Aside from the production and survivability aspects of an effective program of pest control, Christmas tree growers have some direct economic and marketability benefits to consider regarding IPM.

In the marketplace, Christmas tree growers face direct competition from manufactured or, “fake” trees. According to data available from the National Christmas Tree Association and other sources, sales of grown Christmas trees have been challenged significantly by inroads made by the manufactured Christmas tree industry. Industry efforts to make real Christmas trees the trees of choice have increasingly convinced the environmental industry to recommend real trees as the best choice for the environment. IPM affords a marketing positive to Christmas tree growers especially in terms of the attention paid to reduced use of pesticides and its attention to assuring beneficial insects are not harmed in pest control protocols.

IPM also provides tree growers with a direct financial benefit. The grower who sprays indiscriminately, Pickel comments, will soon find the method is ineffective against many Christmas tree pests. “Many of the conifer pests have a small window of time when they are actually vulnerable to pesticide sprays,” she continues. “Pesticides are not cheap and the application process can eat up time. If growers are just guessing at when to apply these chemical controls, IPM could definitely help them reduce the number of applications they need to make. Also, by using IPM to help them grow healthier, damage-free trees, they may be able to draw a better profit during the Christmas season.”

Growing degree day accumulation

Christmas tree growers desiring to begin implementing IPM on their own farms can ease into an IPM regimen by making use of the extensive information available via the internet. According to Sarah, “A good first step for farmers interested in trying IPM would be to start tracking growing degree day accumulation for their farm. Growing degree days are a way of tracking daily ambient heat accumulation for the purpose of determining when certain insect, mite or plant development events (egg hatch, adult emergence, etc.) may take place. Growers can track these using a simple calculation comparing average daily temperatures to a particular base temperature (50°F for most tree pests).” A detailed explanation can be found in this “Monitoring Trees for Pest Populations” downloadable PDF) or, Sarah says, “Smartphone apps are also available that will give you a growing degree day total for your zip code.”

Comparing the growing degree day accumulation to a chart containing the ranges for particular pest events, Pickel says, “Can at least narrow the window for growers regarding when they can target a particular pest.”

Lending support to other options, Pickel creates a weekly “scouting report” available online and useful throughout much of the northeast. It can be found at Penn State’s Scouting Reports between the end of March and the end of June. The report contains information on current pest activity in central Pennsylvania but is useful in other areas as an indicator of the approximate times pests may begin to become active and, susceptible to treatment protocols.

Christmas tree growers have a huge stake in constantly looking after the health of their trees. Reduced mortality means reduced costs, effective pest control means better quality trees grown economically and able to command the best price when sent to market, and better quality means an enhanced ability to compete on the market with “fake” trees. Integrated Pest Management is an effective and economically efficient management technique plantation owners and small lot farmers can utilize to grow and market Christmas trees profitably.

Cover Photo: Unangst Tree Farms in Bath, Pennsylvania (Photo: Jeff Yeager)