|
|
Christmas Tree Production
|
 |
|
|
Christmas Tree Production
|
|
Based on the Pest Management Survey described below, on the average it takes 1/4 of an ounce of pesticides over the life of the tree to produce it in the field. This value is based on the active ingredient in the pesticides including herbicides, insecticides and fungicides used for an 8-year rotationy. This value is for Fraser fir production in western North Carolina. Other areas of the country produce different species of trees with different pest problems. The value continues to decrease as Christmas tree growers continue to reduce their dependence on pesticides. It is a far cry from one recent national news report that erroneously stated it took as much as 28 pounds of pesticides to produce a single Christmas tree. To learn which materials are used and why, please read farther.
Information on pesticides used in the Christmas tree industry in western North Carolina are based on three pest management control surveys conducted among Christmas tree growers. The first, conducted in 1995 by Dr. Steve Toth, Pesticide Impact Specialist with North Carolina State University, surveyed growers about their 1994 pest control use. The second and third, conducted in 2001 and 2007by Dr. Jill Sidebottom, Mountain Conifer Integrated Pest Management Specialist with the North Carolina Cooperative Extension Service, surveyed growers about their pest control practices in 2000 and 2006. In the first survey, the 294 growers responding produced 6,660 acres. There were 336 growers producing 14,747 acres that filled out the 2001 Pest Management Survey, and 352 growing producing 22,249 acres who filled out the 80-question 2007 Pest Management Survey. Therefore, these surveys were representative of the industry.
The following tables summarize the results, listing the pesticides that are used on at least 5% of the Christmas tree acreage.
| Insecticide/miticide | Percentage of acreage treated in 1994 | Percentage of acreage treated in 2000 | Percentage of crops treated in 2006 |
|---|---|---|---|
| Di-Syston 15 G | 64.6 % | 49.6 % | 31.9% |
| Lindane | 21.7 % | 23.8 % | 1.9% |
| Dimethoate | 2.3 % | 21.2 % | 34.7% |
| Asana | 11.8 % | 16.6 % | 13.3% |
| Lorsban | 5.8 % | 8.4 % | 4.6% |
| Savey | --- | 5.4 % | 3.0% |
| Morestan | 14.3 % | 3.0 % | 0.0% |
| Talstar | 0.0% | 0.3% | 11.9% |
| Thiodan | 0.0% | 2.2% | 6.3% |
| Herbicide | Percentage of acreage treated in 1994 |
Percentage of acreage treated in 2000 |
Percentage of acres treated in 2006 |
|---|---|---|---|
| Roundup | 93.7% | 94.9 % | 89.6% |
| Simazine | 72.2 % | 38.8% | 16.8% |
| Goal | 43.8 % | 20.7% | 10.7% |
| Vantage | 23.9 % | 14.7% | 10.7% |
| Stinger | 22.8 % | 11.7% | 5.8% |
| Garlon | --- | 7.8% | 6.1% |
| Crossbow | 0.9 % | 3.1 % | 5.0% |
More information on these most widely used pesticides can be found at EXTOXNET, the EXtension TOXicology NETwork: http://ace.ace.orst.edu/info/extoxnet/
| Asana | http://ace.ace.orst.edu/info/extoxnet/pips/esfenval.htm |
| Dimethoate | http://ace.ace.orst.edu/info/extoxnet/pips/dimethoa.htm |
| Di-Syston 15 G | http://ace.ace.orst.edu/info/extoxnet/pips/disulfot.htm |
| Lindane | http://ace.ace.orst.edu/info/extoxnet/pips/lindane.htm |
| Lorsban | http://ace.ace.orst.edu/info/extoxnet/pips/chlorpyr.htm |
| Roundup | http://ace.ace.orst.edu/info/extoxnet/pips/glyphosa.htm |
| Simazine | http://ace.ace.orst.edu/info/extoxnet/pips/simazine.htm |
| Vantage | http://ace.ace.orst.edu/info/extoxnet/pips/sethoxyd.htm |
| Talstar | http://ace.ace.orst.edu/info/extoxnet/pips/bifenthr.htm |
| Thiodan | http://ace.ace.orst.edu/info/extoxnet/pips/endosulf.htm |
The insecticides and miticides are used to control the following pests in Fraser fir Christmas trees. Most of these pests cause cosmetic damage to the tree, reducing the grade and therefore the value. Heavy damage from these pests can make trees unsaleable for that year. The grower may sell the trees the following year, but only after incurring additional production costs. One pest, the balsam woolly adelgid is not native to the US. Fraser fir is particularly sensitive to it and will be killed. If damage from these pests weren't prevented, it would be impossible to grow good quality Fraser fir Christmas trees. Of all the fir species grown in the United States and Canada, Fraser fir is most susceptible to all these pests.
Balsam Woolly Adelgids (Adelges piceae). Most pests of Christmas trees cause cosmetic damage. The balsam woolly adelgids (BWA) are tiny, soft-bodied insects that appear as white, woolly spots on Fraser fir. The BWA will kill Fraser fir if left untreated. This adelgid is native to silver fir of central Europe, and was introduced to this continent before 1900. This pest moved into the southern Appalachians in the 1950's and has caused the destruction of the Fraser fir in the natural stands. There are no native predators of the BWA found in the US that specifically attack this pest.
These adelgids are very small and difficult to
see. It takes several months for trees to develop
symptoms of insect damage. Because of this, the number
of adelgids can increase unnoticed and cause serious
losses for unsuspecting growers. Luckily, adelgids
take a year or more to spread to many trees, so through
careful scouting and conscientious control, serious
losses can be avoided. Infested trees must be sprayed
as soon as adelgids are observed with a high-pressure
sprayer. The primary symptom of balsam woolly adelgid
attack is a flat top or weak leader. Other symptoms
include dead shoots or branches, swelling around
the shoot nodes (gouting), reduced shoot growth,
a stiff trunk, and growth rings with red, hard wood
instead of the healthy, creamy white wood (observed
when trees are cut).
Treating for the balsam woolly adelgid is the most costly of all insecticide treatments. A two-man crew using a high pressure sprayer can only treat 1 to 2 acres a day. Growers used lindane in the past to control this pest, but this is no longer manufactured. Now growers are using Asana, Thiodan, Astro or Talstar to control the woolly adelgid. Most growers try to treat only once or perhaps twice in a 5 to 10 year rotation. (A rotation in the time from planting in the field until the Christmas tree is harvested). When people have untreated Fraser fir in their yards, this will increase the presence of this insect and require neighboring Christmas tree growers to treat more.
For more information on the balsam woolly adelgid
see Christmas
Tree Note 020.
http://www.ces.ncsu.edu/fletcher/programs/xmas/ctnotes/ctn020.html
PDF 
CTN
020: http://www.ces.ncsu.edu/fletcher/programs/xmas/ctnotes/ctn020.pdf
Balsam Twig Aphids (Mindarus
abietinus). Balsam twig aphids are small,
pale green aphids that feed on fir and spruce trees
in the spring. Feeding on the new growth of Fraser
fir often results in permanently curled needles.
Heavy infestations can also stunt growth. Trees to
be harvested in the fall can be made unsaleable by
heavy BTA damage.
This aphid is common in western North Carolina and can cause severe damage. It is currently recommended that Fraser fir Christmas trees should be treated the last two years before sale. Most growers use Di-Syston to control twig aphids because it can be applied quickly, but other insecticides will control this pest as well.
For more information on twig aphids see Christmas
Tree Note 019 . http://www.ces.ncsu.edu/fletcher/programs/xmas/CT-notes/CTN-019.html
PDF CTN
019: http://www.ces.ncsu.edu/nreos/forest/xmas/ctn019.pdf
Spruce
Spider Mites (Oligonychus
ununguis). These mites are tiny, soft-bodied
pests that suck sap from the needles of conifers. Spider
mite-infested needles first appear off-color from a
distance, and speckled or stippled when viewed closely.
As the number of mites increases, the damaged needles
can become rusty, bronze, or brown in color by late
summer or early fall. In addition, webbing produced
by the mites is visible on the needles of heavily infested
trees. Heavily damaged needles drop prematurely. Damage
is permanent.
Most growers also get full season control of mites when they use Di-Syston in the spring to control twig aphids. Savey and Morestan are also used to control spider mites.
For more
information on spider mites see Christmas
Tree Note 029.
http://www.ces.ncsu.edu/fletcher/programs/xmas/ctnotes/ctn029.html
PDF CTN
029: http://www.ces.ncsu.edu/fletcher/programs/xmas/ctnotes/ctn029.pdf
Rust
Mites(Nalepella spp.). Rust mites are eriophyid mites, a group
of tiny, elongated mites with four legs instead of eight, that require a hand
lens or microscope to see. They feed on the needles of several conifers including
white pine, Fraser fir and hemlocks. On white pine, they cause the needles to
turn brown and die. Damage is usually confined to an area on the upper southeast
portion of the tree. On Fraser fir, damaged needles appear bronze or rust colored,
and may be on one side of the tree or throughout the tree. Damaged needles often
shed prematurely. Rust mites are more common during long, warm springs and often
disappear in the summer. Trees should be scouted to determine if treatment is
necessary. Growers commonly use dimethoate or horticultural oil to control rust
mites.
For more information on rust mites see Christmas
Tree Note 034.
http://www.ces.ncsu.edu/fletcher/programs/xmas/ctnotes/ctn034.html
PDF CTN
034:http://www.ces.ncsu.edu/fletcher/programs/xmas/ctnotes/ctn034.pdf
Rosette Bud Mites (Tricetacus spp.). Rosette buds are deformed buds on Fraser fir. They are larger than normal buds and are rounded instead of pointed. Rosette buds usually do not break in the spring. If they do break and develop, they form multiple, weakened shoots. If many rosette buds are found on a tree, the tree develops holes in the canopy, especially if the tree is young when first affected. This decreases the quality and marketability of the tree.
Rosette buds are more common at higher elevations and in specific counties of western North Carolina. Rosette buds are caused by an eriophyid mite similar to rust mites except that it produces a gall, in which it lives throughout the year, where the bud should be. Growers use dimethoate to control rosette bud mites. Typically the grower will only need to treat once in a rotation to control this pest well enough to produce a quality Christmas tree.
For more information on rosette
bud mites mites see Christmas
Tree Note 018A.
http://www.ces.ncsu.edu/fletcher/programs/xmas/CT-notes/CTN-018A.html
PDF CTN
018A: http://www.ces.ncsu.edu/nreos/forest/xmas/ctn018a.pdf
Growers are encouraged to use Integrated Pest Management (IPM) to control pests. Integrated pest management is a system of pest control methods that uses appropriate cultural practices and pesticide selection to reduce pest problems. Scouting is key to IPM.
Most pests of Christmas trees can cause considerable damage if left untreated. However, applying pesticides without prior knowledge of pest numbers in a field wastes pesticides, is harmful to the environment, and can actually cause outbreaks of secondary pest problems. Therefore, scouting fields on a regular basis to estimate pest numbers is imperative. Growers must use a handlens and tree symptoms to find pests in the field. Scouting occurs on a regular schedule with multiple trips to the field. In the 2007 Pest Management Survey, 71.5% of growers thought they scouted more than they did five years ago.
Other IPM practices that growers use to combat pests include: site selection, early harvesting of damaged trees, proper shearing and fertility practices, encouraging natural predators by keeping ground covers around trees and the carefully selection of pesticides, and not interplanting young trees among older trees (pests get on the smaller trees sooner than they would have).
All growers use at least some IPM methods. However, everyone can improve. That's why the NCCES county agents continue to work with growers to help them do things better and safer.
Growers prefer using herbicides to mowing or using a weedeater for several reasons. From the grower's point of view, it's quicker and cheaper to apply a herbicide than to mow. However, it's also better - both for the tree and for the environment. Mowing and weed eating can damage the bottom limbs on trees and even kill trees if the trunk is girdled. Mowing also encourages grasses to grow, which can choke out trees or grow up into the tree making weak bottoms. However, mowing is also less environmentally friendly because of the gasoline and oil required to run them. Most herbicides are applied with backpack sprayers which are pumped manually.
Many growers use a technique called "weed suppression." Originally developed at North Carolina State University by Dr. Walt Skroch and others, weed suppression uses lower than labeled rates of herbicides to stunt rather than kill weeds.
For instance, Roundup is labeled at 32 to 160 ounces formulation per acre. Growers use rates of 4 to 8 ounces per acre to stunt the weeds so that they don't grow too tall. This treatment lasts 4 to 6 weeks before another application is required. Growers may treat two or three times through the growing season with Roundup at low rates, then come back in the fall and treat problem weeds such as briars and poison ivy at the full rate to eliminate these weeds.
This type of ground cover management results in a shift of common ground covers away from grasses which are competitive to the tree to small woodland perennials that aren't killed by low rates of Roundup. Clover is a common groundcover that fills in the places between trees with this type of management practice, as are dandelions, nimblewill, wood sorrel, and violets. Clover and bird's foot trefoil are also being sowed by growers in cleared land or other sites where appropriate ground covers are not present; these are then managed further through weed suppression with Roundup.
The other commonly used herbicide is Simazine. This is a pre-emergent material that keeps seeds from growing. Simazine is often used in a 18-24 inch strip under young seedlings to keep weeds from overgrowing these smallest trees. The use of Simazine continues to decline in western North Carolina.
Prepared by Jill R. Sidebottom, PhD, Area Extenson Specialist, College of Natural Resources, NCSU
Recommendations for the use of chemicals are included in this publication as a convenience to the reader. The use of brand names and any mention of commercial products or services in this publication do not imply endorsement by the North Carolina Cooperative Extension Service nor discrimination against similar products or services not mentioned. Individuals who use 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 and examine a current product label before applying any chemical. For assistance, contact an agent of the North Carolina Cooperative Extension Service in your county.
Mountain Horticultural Crops Research & Extension Center
455 Research Drive
Mills River, NC 28759
Phone: 828.684.3562 ~ Fax: 828.684.8715
Email: jill_sidebottom@ncsu.edu
Web Crafter: Anne S. Napier ~ Email: anne_napier@ncsu.edu
Updated November 7, 2007
