Focus on Aphid Control

The balsam twig aphid and Cinara aphid are very different types of pests. The BTA feeds on the developing shoots causing needle curl. Cinara aphids feed on trunks and branches, seldom damaging the tree, but causing a problem when they end up on the cut tree in the home.

Even though they are different, there are several good reasons to group these pests together when it comes to control.

The same insecticides are affective on both.
They can both becontrolled in the fall during the same treatment window.
They are really only a problem to worry about as trees near harvest size (see below).

Cultural Controls

Avoid Excess Nitrogen

Aphids are typically more of a problem when plants are fertilized excessively with nitrogen fertilizer. This is because the added nutrition is also a nutritional bonus for the pest. As Christmas trees near harvest and get larger, their nitrogen needs become greater and it is more important to maintain a good green color. In order to maintain high enough nitrogen levels and yet reduce the impact of nitrogen on aphid pests, consider splitting the nitrogen application between the spring and early fall

Maintaining Good Groundcovers

Ground covers supply habitat for natural predators. There are many predators that feed on aphids including lady beetle adults and larvae, hover fly larvae and green lacewing larvae. The adult hover flies and lacewings feed on pollen and nectar and not pests. By keeping flowering ground covers around trees, and field borders to grow up in grasses and flowers that are allowed to bloom and go to seed, a habitat for these important predators is provided.

When Chemical Control is Necessary

When to Treat for BTA

There is no reason to control BTA in young trees. If there is damage, the tree typically grows that much more the following year. Start treating for BTA the year before you will be cutting trees out of the block so that all trees will have two years of good growth when marketed.

However, even if BTA control is important because of the time in the rotation, it's not necessary to get complete control. Studies have indicated that most consumers don’t view the needle curl associated with BTA as problematic when picking out their special tree. Most growers in western NC have indicated that they would market a tree that had up to10% of the needles with some curl. Therefore, 100% control of BTA is not necessary.

organic Fraser fir field

Damage that is found in the spring is typically gone by the time the foliage hardens off in the summer as long as there is enough rain for good shoot elongation.

These organic trees have never been treated in the spring for BTA, yet few trees have any damage. Organic growers of Fraser fir in western NC have found that if they do not treat for twig aphids, there is seldom much needle curl. There are enough predators to clean up the problem.

When to Treat for Cinara Aphids

Cinara aphids attract predators because they live in large colonies. The aphid colony pictured here in May will certainly be gone by November. It is not necessary to control Cinara aphids in the spring and summer as they will not damage trees. However, if aphid colonies are found in blocks of trees to be harvested that year, many growers spot treat a few trees just to keep the population from potentially increasing in the fall.

It is recommended that all Fraser fir in western North Carolina be treated in the fall for Cinara aphids as a preventative treatment. Cinara aphids reproduce by having live young. Therefore even a few individual aphids at harvest may multiply rapidly in the home, causing a problem for the consumer. As the weather gets colder in the fall, many Cinara aphid colonies move lower into the tree, feeding on bottom branches where it is difficult to find them.

An important question is how early in the summer can you treat for Cinara aphids and get control. Most materials applied before August will not last long enough to control Cinara aphids. Treatments made in August and September should be sufficient to keep Cinara numbers from building back up unless there is a heavily infested block of trees close to the treated field. Treatments made in October should of course provide good control.

Chemical Control of Aphids

Aphids can be controlled in Christmas trees with any application method. However, coverage is still important. If using an air-blast mistblower, do not try to treat too many rows at one time. Cinara aphids especially can be lower in the tree and difficult to reach.

Pests Controlled	Treatment Description	Treatment Window
BWA BTA (for next year) SSM Cinara aphids	SNIPER (or other bifenthrin product): Bifenthrin products include Talstar and Wisdom. Fall applications of Sniper (August until harvest) are best for controlling both Cinara aphids. This product has low mammalian toxicity, so it is safe to use on trees to be harvested. Bifenthrin products have also effectively controlled BTA for the following spring when applied in the fall. Be sure to scout the following spring to make sure treatments were effective. Anything that compromises coverage will reduce effectiveness. If HRM is found in the field, consider adding a miticide such as ENVIDOR to reduce the likelihood of having to treat for mites the following spring. For more information see: Focus on Mite Control. Negative impacts on natural predators and increases of SSM and HRM are minimized by treating in the fall.	Fall (August through harvest)
BWA BTA (for next year) Cinara aphids	OTHER SYNTHETIC PYRETHROIDS such as ASANA or ASTRO: These products offer excellent Cinara aphid control and typically good control of BTA the following spring when applied in the fall. Be sure to scout in the spring to make sure treatments were effective. Anything that compromises converage will reduce effectiveness. If mites are present in the fall, add a miticide. For more information see: Focus on Mite Control. Negative impacts on natural predators and increases of SSM and HRM are minimized by treating in the fall.
BWA BTA (for the coming spring)	SYNTHETIC PYRETHROIDS: Synthetic pyrethroids such as Asana, Astro, Sniper and other bifenthrin products (Talstar and Wisdom) will control both BWA and BTA when applied in winter months. Negative impacts on natural predators the resulting increase in problems with of SSM and HRM are also minimized. Mite eggs cannot be controlled at this time even with miticides that kill the egg. The reason is that these products need an egg that is nearing hatch and in the winter mite eggs are fully dormant.	Winter (December through March)
BWA BTA eggs HRM SSM eggs EHS (partial) Cinara aphids	HORTICULTURAL OIL: A 2% horticultural oil solution will control BWA nymphs. Applying oil in mid-March will also control BTA, HRM, and give some control of SSM and EHS. For more information on the use of oil, see: Organic Pest Control in Fraser Fir Christmas Trees. Cinara aphids will need to be controlled again in the fall if trees are to be harvested as they could reenter the field at that time	March
BTA SSM (not eggs) HRM (not eggs) Cinara aphids To add BWA and EHS control	DIMETHOATE: Dimethoate applied by itself will control BTA and Cinara aphids and provide a knock-down of both SSM and HRM. If mites are a problem, consider adding a miticide that controls eggs. For more information see: Focus on Mite Control. Cinara aphids will need to be controlled again in the fall if trees are to be harvested as they could reenter the field at that time. DIMETHOATE PLUS ASANA or DIMETHOATE PLUS SAFARI: Adding either Asana or Safari (not both) to Dimethoate will also give BWA and EHS control. Better control of scales will occur closer to bud break.	Spring (late March through budbreak)
BWA BTA SSM Cinara aphids	SNIPER: Sniper applied by itself will control BTA, Cinara aphids, BWA and SSM. If cones have broken, BTA control will be better if these are removed before treating as the aphids will be protected in the cones. If HRM are a problem, consider adding another miticide. For more information see: Focus on Mite Control. The use of Sniper in the spring may make rust mites worse the following spring, so be sure to scout. Cinara aphids will need to be controlled again in the fall if trees are to be harvested as they could reenter the field at that time.
BWA BTA Cinara aphids	ASANA: Asana applied by itself will control BTA, Cinara aphids and BWA. If cones have broken, BTA control will be better if they are removed before treating as the aphids will be protected in the cones. If mites are a problem, consider adding a miticide. For more information see: Focus on Mite Control. The use of Asana in the spring may make rust mites worse the following spring, so be sure to scout. Cinara aphids will need to be controlled again in the fall if trees are to be harvested as they could reenter the field at that time.
RBM BWA BTA Cinara aphids	MOVENTO: Movento applied by itself will control BTA, Cinara aphids, BWA and RBM. Movento takes some time to be effective, so apply at least two weeks before budbreak. If mites are a problem, consider additing a miticide. For more information see: Focus on Mite Control. Cinara aphids will need to be controlled again in the fall if trees are to be harvested as they could reenter the field at that time.

Additional Pest Focus Pages:

Focus on rosette bud mite control — If rosette bud mites are your problem, look no further for the control of all pests except Cinara aphids on market size trees.
Focus on elongate hemlock scale control — If you don't have rosette bud mites but do have elongate hemlock scale, look here for control of all your pests.
Focus on balsam woolly adelgid control — No rosette buds or scales but you do have woollies? Look here for control.
Focus on mite control — Mite control can be added on any time other pests are being controlled. Look here for added information on mite control.

Pest Control in Fraser Fir Christmas Trees