Forest Pests

According to The Canadian Council of Forest Ministers National Forestry Database (nfdp.ccfm.org/index_e.php). Trees in Canada have always been subject to damage by insects. Today, native insects that significantly damage forests include spruce budworm, tent caterpillars and bark beetles. Other non-native insects also cause extensive damage. Examples are balsam woolly which feeds mainly on balsam fir and gypsy moth which attacks many hardwood species. Alien species often do more damage than native ones because they have no natural predators or diseases here to limit the expansion of their populations. Forest insect pests acting in combination with diseases are even more damaging to forests.

Damage from insects may limit the economic use of tree species and/or render areas of forests unsuitable for recreation, wildlife habitat, or other uses. The biodiversity of forests may also be altered by the effects of insect damage.

Zimmer Air Services offers Forest Pest Management Spray Programs for both rural and urban areas. We operate under the strict guidelines set out by Transport Canada and the Ministry of the Environment as well as Health Canada. The products used and application of those products are pre-approved and monitored for saftey and effectiveness.

Hemlock Looper

(Eastern) Hemlock Looper damage is visible on conifers during epidemics in late July and early August. The trees turn a reddish colour, which is very characteristic of hemlock looper outbreaks. Needles damaged by feeding larvae dry out, turn red and drop in the fall.

Hemlock looper outbreaks develop and subside very suddenly. They spread quickly and can cause the death of balsam firs in the first year that damage is detected.

There are four or five larval stages, depending on the region of Canada. When mature, the larvae look for a pupation site. During heavy infestations, trees are covered with silk strands produced by the larvae as they descend the tree trunks in search of food or pupation sites.

The insect has only one generation a year and over winters in the adult stage.

Native to North America, the hemlock looper has destroyed several million hectares of conifer forests in eastern Canada over the years. Between 1910 and 1975, hemlock looper outbreaks caused timber losses estimated at 12 million cubic meters in Newfoundland and 24 million cubic meters in Quebec. Since then, infestations in the Lower St. Lawrence, Gaspe Peninsula, Anticosti Island and, most recently, the North Shore, have also resulted in timber losses.

For more information about (Eastern) Hemlock Looper visit Natural Resources Canada

Gypsy Moth

The reaction to gypsy moth invasions ranges from complete horror to a total lack of interest. However, almost everyone has some level of concern when the gypsy moth caterpillars cause.

• Noticeable defoliation of trees
• Drop their feces on everything under the trees
• Hairy caterpillars begin to crawl over everything in their path making outdoor enjoyment a real challenge!

Tree Damage

Tree Damage is caused by the insect larvae, or caterpillars, which emerge from their eggs beginning in early spring and continuing through mid-May. The larvae move to the leaves of trees and begin to eat, mostly at night. During daylight hours, larvae generally seek shade from the sun but feeding can occur in daytime in heavy infestations. Feeding will continue into late June depending upon a variety of factors.

Trees Affected although the Gypsy Moth Caterpillar prefers species such as oak they will feed on most trees and are the most serious pests of deciduous trees.

Gypsy Moth Control

There are a few chemical pesticides registered for caterpillar control. However, people are concerned about the effects both on the environment and on human populations. Most people prefer not to come into contact with chemical pesticides if they can avoid it.

So, how can we avoid coming into contact with synthetic pesticides, yet control the gypsy moth? One answer is to use products derived from a naturally occurring, soil dwelling bacterium, called Bacillus thuringiensis, or “Bt” for short.

Since it was first registered in the US in 1961, dramatic advancements in the development of Bt strains have occurred. Btk “Kurstaki” effect only the lepedopteran family of caterpillars of which Gypsy Moth fall into. The actual mode of action is simple. The bacterium produces a crystal protein that kills the cells lining the insect gut - they eat, they die. The interesting thing about Btk is that if ingested by other beneficial insects, birds, fish, other animals and people - it is harmless.

Why Aerial Spray?

The aerial application of Bt has been determined to be the safest and most effective method of reducing exploding populations of gypsy moth in forested, semi-rural and urban areas. Gypsy moth larvae feed throughout the canopy of trees. To kill the caterpillars, Bt must be applied to foliage (needles and leaves) and then be eaten by gypsy moth larvae. Trees come in many shapes and sizes and are located in all types of locations and terrain. Some of these locations may be very difficult to access from the ground. Aerial application of Btk is the most effective and cost-efficient method of applying Btk over a large area and reach foliage located in poorly accessible locations. Furthermore, and most importantly, over 30 years of aerial application on human populations have revealed no short or long-term adverse effects to human or environmental health. Btk is an extremely safe biological insecticide.

Aerial application of Bt is the preferred method for suppressing gypsy moth populations that are widespread. There are several important advantages of using this method over other forms of treatment.

• Safe - Btk is harmless to non-target organisms. Because there are minimal health risks and it does not harm the environment, Btk can be applied over populated areas without any buffers for water bodies.
• Effective - Aerial sprays have been proven over several decades of use to be highly effective at achieving the desired level of control of gypsy moth and other forest pests.
• Fast - treatment can be completed in only a few hours vs. ground applications which may take several days to treat a much smaller area. The majority of droplets will have reached the ground within 10 minutes of application.
• Complete coverage - droplets are evenly spread throughout the target area and, most importantly, are able to penetrate crowns of trees no matter how high they are. Ground application of Btk is limited by access, terrain, and the height and density of the target vegetation.

Tent Caterpillar

Increasing tent caterpillar populations can cause extensive defoliation risking tree mortality if left unchecked. High populations may also decrease your ability to enjoy outdoor activities when the tent caterpillar is in the larval stage and actively feeding. Check your wooded areas in early spring for the presence of egg masses to determine if treatment is warranted. If some degree of defoliation was present during this years growing season, the possibility for increased populations in following years exists. Populations will eventually collapse from natural causes, however, this may take a few years without intervention.

Damage

When extremely numerous, the caterpillars feed upon nearly all green foliage, including shrubs, fruit trees, some garden crops, and even spruce and tamarack in wooded areas.

The first noticeable sign of an infestation is clusters of tiny black caterpillars feeding on opening buds and developing foliage in mid to late May. As the season progresses the caterpillars eat more leaves, until all the foliage is consumed. In the last half of June, the mature caterpillars migrate in search of new food supplies or suitable cocooning sites. They are easily recognizable by their dark brown body with a broad band of blue along each side and prominent row of white or cream, keyhole shaped spots down the back.

Application Timing

Tiny caterpillars will emerge from the over-wintering eggs in the spring. Greatly dependant upon the weather, treatment usually occurs in the latter part of May into the early part of June. Two applications will control the Forest Tent Caterpillar if carried out at the optimum time when the majority of the hatch has occurred. Only B.t. products are used, which are formulated from naturally occurring bacteria providing an environmentally sound alternative to chemical pesticides. Caterpillar feeding will cease almost immediately which will result in a high degree of larval control and mortality. The B.t. products applied offer no hazard to humans, pets, animals or other insects so you may resume outdoor activities at any time following the application.

Treatment

Bacillus Thuringiensis (B.t.) is a naturally occurring biological insecticide which only affects leaf eating caterpillars such as the Gypsy Moth Caterpillar, Tent Caterpillar and Spruce Budworm. It will not harm other insects, birds, mammals or plants. As a precaution, however, we do recommend that persons with severe allergies remain indoors or leave the area at the time of application.

B.t. is effective in very small quantities of less than one liter pre acre. At this application rate, it is dispersed from the helicopter in very fine droplets which is very often not visible from the ground. These fine droplets drift down and land on the foliage. You may be able to see fine droplets as the leaves, vehicles or other items in the treatment area. It is not harmful to painted surfaces and can be washed off easily with soap and water.

The B.t. product has additives to achieve rain fastness, however, if rain is in the immediate forecast we would not spray.

The caterpillars ingest the B.t. with the foliage. Within hours they will stop feeding and die within a few days. Two applications of the B.t. product is recommended for maximum effectiveness.

Maintaining a no-spray buffer zone between the treatment area and surrounding surface water is not necessary when applying B.t. products………B.t. is a safe and effective biological insecticide.

Please contact us for all your Pest Control needs!