Madison Park

Thank you to all of our residents, businesses and organizations who helped band our trees this fall.  Tree Banding is an important first step in controlling the fall cankerworm population. 

Even with Charlotte's best efforts, the fall cankerworm populations are still high enough to endanger our trees.  With the support of the City Council, the City recommends a second step in the infested areas - aerial spraying.

Aerial Spraying

The spray we will use contains Bt, a naturally occurring substance used for decades by organic farmers and gardeners.  This natural control, which reacts with the acids found in the digestive systems of cankerworms, has no adverse affects on humans, honeybees, pets, wildlife, fish or groundwater.  The spraying must be done in the early spring when a large number of cankerworms are hatched and feeding at the tops of our trees. 

The dates for spraying will be determined by local weather conditions and the hatching of the cankerworms.  The City will work with the local media to notify residents when the spraying will occur. 

To receive cankerworm updates, sign up for the Notify Me service on this webpage.  You will be notified of any updates to the cankerworm website. 

Residents can also call 311 in late March for more specific spraying information.

Questions and Answers about Aerial Spraying

• Why is the City conducting an aerial spraying? Charlotte has been experiencing infestations of the fall cankerworm for the last 20 years. By eating the leaves off of large, old trees in the spring, the cankerworm weakens the trees and causes them to die. We have been able to help slow them down with our banding programs. However, their numbers and the size of the affected area have increased to the point many of our trees are at risk.
• When will the spraying occur? The aerial spray will take place between late March and early April depending on weather and the emergence of the caterpillars.
• What material will be sprayed? The City will be contracting to aerially spray a naturally occurring, organic substance called Bt (Bacillus thuringiensis). 
• What are the effects of Bt on the environment? The variety of Bt we will be using only affects caterpillars that are actually feeding at the time of the spray. Sunlight quickly deteriorates Bt until it is gone within 48 to 72 hours of the spray.
• How will citizens be notified of the spraying dates? The City will work with the local media to notify citizens of the parts of Charlotte that will be sprayed and when.  Updates will also be posted on our website, cankerworm.charmeck.org, and residents can get up-to-date spraying information by calling 311.
• How safe is it to fly low over the city? The FAA will have to approve the qualifications and congested area plans for the aircraft that will be used over Charlotte. Many cities and towns throughout the United States are sprayed by low-flying aircraft every year.
• Has Bt been sprayed in Charlotte before? The City has sprayed for fall cankerworm in 1992 and 1998.
• Has Bt been sprayed over populated areas before? Bt has been sprayed annually in North Carolina for the control of gypsy moths. Areas in and around Hendersonville and Morganton were sprayed for the moths last year at a much higher rate than we will use in Charlotte, with no detrimental effects.
• Have there been any problems with spraying over populated areas? Bt has been used for decades over cities and towns throughout the United States and Canada. There have been no reports of any adverse effects of these sprays.
• Will the spray aircraft and materials be protected from potential terrorists? The contractor that is awarded the bid will be held responsible for securing their aircraft and equipment. The City will be inspecting these locations for compliance.
• Will the spray affect my children? There have been no known affects of the aerial spraying of Bt around children.
• Should I bring my children inside during the spray? You are welcome to do that, but it is not required.
• Will the spray affect my pets? There have been no known affects of the aerial spraying of Bt around animals or fish.
• Should I bring my pets inside during the spray? You are welcome to do that, but it is not required.
• Will the spray affect my car's paint? Over the many years of use of Bt in aerial spraying, there have been no documented cases of harm to automotive paints.
• Should I wash my car after the spray? The carrier for Bt is similar to tree sap. The sooner you wash your car after the aerial spray, the easier it will be to get off of the paint.
• Will the entire city be sprayed? The treatment area covers almost 70,000 acres or 40% of Charlotte. There are some exclusion areas within this zone, such as the interstates, heavy industrial areas and uptown Charlotte, that are not necessary to spray since they have no trees. For a copy of a map of the spray area, see our website at cankerworm.charmeck.org.
• Why are only certain neighborhoods sprayed? The City has been monitoring the cankerworm populations every winter for the last 15 years. We use this information to predict heavy defoliation the following spring. We also use this information coupled with aerial surveys of damage to determine the neighborhoods where aerial sprays need to be applied. Your neighborhood has not shown high enough readings to warrant an aerial spray. We will continue to monitor the populations in the future. If your neighborhood becomes heavily infested, it will be scheduled for programs by the City to help control this destructive insect.
• If the City is not spraying certain areas within the infested areas, won't that cause the fall cankerworm to re-infest our neighborhoods? Certain urban areas that have very few trees are being excluded from the spray. This saves the cost of aerial spraying in places where the cankerworm is minimal. The exclusion areas will not provide a place for cankerworms to re-infest surrounding neighborhoods.
• How much will the aerial spray cost? This will depend on which bidder is accepted for the aerial spray. Bids are due March 3^rd. The selection will take place that week.

 I took this from the Charlotte Mecklenburg web site under canker worms.   It does appear we are indeed scheduled to be sprayed as the poster has noted.   It looks like going over toward Archdale which will include parts of Montclaire.

According to the Charlotte Mecklenburg web site the spray last for 48 to 72 hours and is broken down by sunlight.

 http://www.charmeck.org/Departments/city+engineering/use+our+services/landscaping/fall+cankerworm.htm?header=cankerworm%2echarmeck%2eorg#top

 If anyone wishes to band trees next fall we can certainly do this with enough participation with the help of a grant.   We are not limited to just one grant if one of the grants is for tree banding. 

Just to be safe if indeed we are sprayed I am going to stay inside on those days and keep my pets inside. 

 I am going to post a second related article on the product being used that mentions the spores that the initial poster shared in his post.

Martin Doss

President of Madison Park HOA

Integrated Pest Management

BT: An Alternative to Chemical Pesticides

What is BT?

BT is an abbreviation of the scientific name of a species of bacteria, Bacillus thuringiensis, that kills some groups of insects.

BT occurs naturally and is commonly found in soils worldwide. It was first discovered infecting silkworms over 90 years ago in Japan, where it became known as Sotto disease.

For many years, the possibilities of using this naturally occurring organism were not recognized, but in the 1950s research began in earnest on its effectiveness as a pest control product.

A commercial BT product was first registered in the United States in 1958; by 1960 it was cleared for use on food crops and in 1961 it was registered for use in Canada. It is now the most widely used naturally occurring pest control product in the world.

It is important to realize that BT is not a synthetic chemical. BT products contain the highly specialized protein crystals and dormant spores of bacteria. These are only activated when they are eaten by a susceptible species of insect. Unlike broad spectrum insecticides, BT is highly specific - that is, it affects only certain species of insects and has no effect on others.

How Does it Work?

BT begins to work after a caterpillar eats a piece of leaf with BT crystal proteins and spores on it (caterpillars are the immature stage of butterflies and moths).

Susceptible caterpillars have a strongly alkaline digestive tract (in contrast, humans and other animals have acidic digestive tracts). When the crystals reach the caterpillar's gut, they dissolve in the alkaline conditions and release the proteins contained in the crystal.

Through a series of complex biological processes, the proteins disrupt the lining of the gut, which causes the caterpillar to starve. Infected caterpillars may not die for several days, but they usually stop feeding immediately because their digestive tract is paralyzed by the activity of the crystal proteins.

What are BTK and BTI?

Since BT was first discovered, researchers have found many different subspecies of BT, some of which are now commercially useful because they infect different groups of insects.

BTK is the abbreviation for Bacillus thuringiensis var. kurstaki, the subspecies that is currently used most widely for control of caterpillars. BTI stands for Bacillus thuringiensis var. israelensis, a subspecies that kills young larvae of mosquitoes and black flies. BTI is used widely in British Columbia in mosquito control programs. A new subspecies that has been registered recently is Bacillus thuringiensis var. tenebrionis, which affects the larvae of some species of beetles.

Is BT Safe to Use in Yards and on Food Plants?

BT is not a synthetic chemical - it is a naturally occurring organism. It is non-toxic to humans, other mammals, birds, fish and most insects, therefore it is a good choice for use on food crops. BT products have been approved for use on organically grown food for many years.

Does BT Harm Earthworms, Honeybees or Other Beneficial Species?

Each BT strain infects a relatively narrow range of species. Studies have shown that predatory insects, such as lady beetles, are not at risk if they eat an insect that has been infected with BT. BT does not infect earthworms, nor does it kill honeybees or many other species of insects. BT is an excellent choice for control of many pest caterpillars because it does not harm predatory insects, birds, snakes and other animals that keep pest numbers low in the yard and garden.

Does BTK Harm Butterflies?

Many caterpillars, which are the immature stage of butterflies and moths, are potentially susceptible to BTK. Although the effects of BTK have not been tested on the caterpillars of every species of butterfly, we do know that it does not harm the adult butterflies, their eggs or the chrysalis stage (an immobile stage, when the caterpillar turns into a butterfly within a silken case).

Generally, only the younger caterpillars of susceptible species are killed by the product and even they must eat a sufficient dose of BT to be affected. To be effective on pest caterpillars, sprays must be timed to coincide with the most susceptible age of insect because BT only lasts for a short time in the environment. Unless butterfly caterpillars are in the same place at the same time as the target caterpillars, they would not be at risk of being infected.

To minimize the impact of sprays on non-target caterpillars in a home garden, homeowners should spray only if they are sure the caterpillars are causing significant damage (caterpillar damage often looks worse than it is; plants usually recover quickly by growing new leaves).

How Long does BT Last in the Environment?

There have been numerous studies on how long BT lasts in the environment. In general, it has been found that there is a rapid decline in the ability of the bacteria to infect insects within 12 to 48 hours after it is applied.

After the product has been mixed with water and sprayed onto leaves, it is destroyed by the ultraviolet radiation in sunlight within a few days. It is also degraded rapidly by high temperatures and substances on plants leaves. It is also washed from leaves into the soil by rainfall.

In the soil, where BTK spores are protected from sunlight, they remain dormant. The spores of BTI may also remain dormant in the mud at the bottom of a stream or pond for several months. The spores cannot germinate in either soil or water - to do this they must be eaten by a susceptible insect.

What is in Commercial BT Products?

To enable BT to be made into a commercial product, the bacterial cultures and the food medium the bacteria are grown in are mixed with other ingredients. These are added to make the products stable, mix easily in water and stick to leaves. BT is so fragile in the environment that ultraviolet protectants to shield it from the sun are usually also added.

These ingredients make up approximately 5% of the concentrated product, which is later diluted with water to make a spray. The largest component of any BT spray is water; for example, a common BT product sold for gardeners is diluted 150 - 300 times before spraying.

These additional ingredients are part of the registered product formulation that is submitted to the federal Pest Management Regulatory Agency for registration. Under current regulatory practice in Canada, all ingredients in pesticides are known and are tested for toxicity in the whole formulation. They are approved by federal health professionals when the product is approved for registration. BT products registered in Canada are required to meet stringent quality standards similar to those used in the food industry.

Why Should we Use BT Products?

Using BT instead of a chemical insecticide to control caterpillars is an important step in reducing your exposure to chemicals in the environment. It is also the best choice to avoid harming the many native beneficial species of insects and other animals.

As with all pest control products, BT should be used only when you know that control measures are necessary. BT lasts for only a few days once it is sprayed, therefore spraying it before caterpillars appear is a wasted effort.

Are BT Products Available to Home Gardeners?

At any garden centre, you can find one or more products containing BTK to control caterpillars such as cabbage loopers, imported cabbageworm, fruit tree leafrollers and other caterpillars that attack garden plants and trees. The products are in powdered or liquid concentrate form that must be mixed in a larger volume of water to make a spray for plants and trees. Products containing BTI are for commercial applicators for use in community mosquito control programs.

Always follow the directions on the label to mix and use the products correctly.

Date: October 1998