FRASER FIR PEST CONTROL PORTAL
Scouting — The Steering Wheel
Getting Direction from Scouting
Recommendations on this website are based on accurate field scouting and will only be helpful if these observations are representational of the field. Without knowing what pests you have, it is impossible to know if, when, or with what you need to treat. Therefore, scouting drives the direction for pest control.
There is no one pesticide or combination of pesticides that will keep trees pest free. All pesticide applications have a cost — not just the cost of the material(s), but also the impact on natural predators and risks to environmental and human health. Often the best pest control is to do nothing at all, but you can safely do this only by accurately knowing what pests and predators are in your trees.
What is Scouting?
Scouting is the regular, systematic, and repeated sampling of pests in the field in order to estimate the presence of a pest and their population levels. Scouting is geared towards the major pest problems and is modified by weather that favors particular pests. In order for scouting to happen, you have to make time for it, just like you would for any other production practice. As you get more familiar with each field and learn where pest problems are found, scouting should take less and less of your time.
Part of scouting is to determine if a particular pest such as elongate hemlock scale or rosette buds is present at all in the field. Once you know these pests are present, scouting is needed to determine if enough trees are affected to warrant an insecticide application. While scouting, not only pests but natural predators are observed which should also be factored into the decision whether or not to treat. Once a pesticide has been applied, scouting is used to determine how well treatments worked.
Scouting Tools
It doesn't take a great deal of equipment to do a good job of scouting. The following tools are useful in scouting though not all are absolutely necessary:
- A good quality magnifying lens with at least 7X power that you can see pests clearly with.
- White plastic plate or something similar to beat the foliage over.
- Flagging to mark problem trees. This should be of a color that is not used in tagging trees.
- Pocketknife to cut off bark samples.
- Clippers to cut off shoots and branches.
- Plastic bags to collect samples in.
- Marker to write on plastic bags such as a sharpie.
- Camera to take photographs of problems. A cell phone camera is typically good enough.
- GPS unit to mark location of problem areas so maps can be developed.
- Map of the field so that problems can be recorded.
- Scouting form so that scouting results can be recorded.
- Shovel for digging in the soil to find grubs or other root problems.
- Soil sample probe, bucket and boxes to determine fertility needs.
Scouting Calendar for Pests
The following is a sample scouting calendar that takes into account when pest problems are easiest to identify. This calendar should be modified depending on your location, what pests you have, and the weather. When the weather is hot and dry, spider mites in particular are more of a problem.
- March/April: In March and April, pests become active. Twig aphids start to hatch by mid-March. Depending on the weather, rust mites and spider mites also start to hatch. The balsam woolly adelgid molts from the overwintering nymph to the adult and may start to lay eggs. During this timeframe, it is important to determine the presence and activity of twig aphids and mites to determine if controls are required before budbreak.
- May: The time right up until budbreak and right after budbreak is important to further monitor twig aphids and mites.
- June/July: During June and July, spider mites may flare up if it is dry. The elongate hemlock scale males mature and produce the protective white fuzz that can be easily seen on foliage.
- August through October: Once tree tops straighten, balsam woolly adelgid can be scouted for by examining trees with crooked tops for the insect. The elongate hemlock scale will have another flush of growth that can be monitored. Rosette buds are clearly formed and the presence and prevalence of this pest can be followed. If it is dry, spider mites can become a problem again. Also be on the look-out for Cinara aphids in trees to be harvested. Early fall is also the time to dig in the soil looking for white grubs.
A scout also typically takes soil and plant tissue samples to determine fertility, and watches for weed problems and weed growth. Soil samples are best taken in the fall to determine fertilizer use for the following year. Weed composition and height should be observed during all scouting trips.
How to Look for Pests
The following techniques are useful in finding pest problems. Be sure to look at the Christmas tree notes of each individual pest for further information on ways to spot each pest.
- Spotting tree symptoms. Tree symptoms of pest damage can be seen from many rows away. Be on the look-out for trees with crooked tops, dead branches, yellow or spotted foliage, white to grayish discoloration of the needles, or needle drop. Look for discolored needles back in the canopy in the lower half of the tree.
- Beating foliage. Hitting foliage forcibly with your hand over something like a white plastic plate will dislodge many pests and predators. This is the best way to monitor twig aphids and to find beneficial predators. Other pests that can be dislodged in this fashion are elongate hemlock scale adults and crawlers, spider mites, and rust mites. Be sure to use a magnifying lens to correctly identify insects.
- Picking a shoot. Some pest either can't be dislodged from foliage or are found at lower numbers by examining tree shoots. Pick a small shoot of the most current growth from back in the canopy of the tree and look on both sides for mites, scales, twig aphid eggs, and woolly adelgid. Sometimes predators are also found in this way, especially predatory mites. To observe scales, look on the underside of foliage, and remove a branch with 2-3 year's worth of growth. Look especially for parasitized scales indicated by a round hole in the center of female scales.
- Examining the bark. To find balsam woolly adelgid, examine the trunk of the tree and along the underside of branches. Cut-off suspect woolly spots with a pocketknife to look at them more closely with a magnifying lens.
- Digging in the soil. Some pests such as white grubs can only be found by digging in the soil. If a tree is stunted or dying, it is also a good idea to dig up roots to examine their condition. Root aphids can be found in this manner as well as roots infected with Phytophthora root rot or fed upon by grubs.
Additional Information on Scouting
For help in scouting Christmas trees, see Scouting Fraser Fir in North Carolina.
In addition to the Scouting Manual, there is information on each individual pest located in Christmas tree notes. Below is a link to these notes and photographs for each important pest.
| PEST | ABBREVIATION | INFORMATION LINK | IMAGE GALLARY LINK |
|---|---|---|---|
| Rosette Bud Mite | RBM | CTN 018a: Rosette Bud Mite on Fraser Fir | Images of RBM |
| Elongate Hemlock Scale | EHS | CTN 037: Elongate Hemlock Scale | Images of EHS |
| Balsam Woolly Adelgid | BWA | CTA 020: Balsam Woolly Adelgid | Images of BWA |
| Balsam Twig Aphid | BTA | CTN 019: Balsam Twig Aphid on Fraser Fir | Images of BTA |
| Spruce Spider Mite | SSM | CTN 029: Spruce Spider Mite in Fraser Fir | Images of SSM |
| Hemlock Rust Mite | HRM | CTN 034: Rust Mites on Christmas Trees | Images of HRM |
| Cinara Aphid | None | Cinara Aphids on Christmas Trees in North Carolina | Images of Cinara aphids |
Fraser Fir Pest Control Portal Informational Pages:
- The Foundation of Pest Control — Cultural Practices
- Insecticides — Just One Tool in the Pest Control Tool Box
- Control Based on Time in Rotation — since not every pest is a problem at every age.
- Control Based on Treatment Window — what pests you can control at different times of year.
- Control Based on Highest Priority Pest — an aid in controlling multiple pests while controlling the most important ones.
- Important Insecticide Application Considerations — includes information on sprayers, labels, application tips, weather considerations, and protecting pollinators.
- Organic Fraser Fir Pest Control
- Disclaimer
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