imagesToday a young woman asked if she should sign an on-line petition urging the BC Government to stop its Gyspy Moth control spraying program.

Unknown-1My initial reaction is, NEVER sign any on-line petition.  But this young woman like so many of her peers has a sense of wanting to engage in her world, to contribute to the well-being of the place, for her family and for other people.  But like most of her friends she has very little time or energy to do a lot of research on matters of importance.  And so rather than do nothing, she’ll read what others claim is factual on theiUnknownr petitions.

Some 15 years (or so) ago I had a summer job with Agriculture Canada doing Gypsy Moth control.  At the time I was in a two-year horticulture program at UCFV and as I recall it was the US Government that offered the money for BC to implement Gypsy Moth control. Because the moth was moving north and west, (laying eggs and hitching rides under RVs and assorted vehicles, as one of its modes of locomotion) the Americans were terrified of the damage this little moth was doing to deciduous trees, particularly in the eastern states.  And the videos we watched during training really were enough to strike terror,……cars sliding out of control on millions of squashed caterpillars, …… swimming pools floating a mass of drowned caterpillars,…..whole stretches of once green forests made brown, almost overnight.

BC wasn’t very worried, I was told, because we have a lot more conifers here, so it was thought that Gypsy Moth would not have nearly the same economic impact.  But the Americans were very worried that if we harboured their enemy it would cross the border and invade them from the North.  So they paid for Canadian college students to chase the moth.


That was undoubtedly the most enjoyable work I have ever done.  My partners and I got to drive about in government vehicles into all the back roads, along rivers, up into the mountainsides, in beautiful summer weather, hanging little orange tent traps set with a pheromone to attract male moths, and Tanglefoot to keep them there as an indication of how many were in a given area.  (Last week, on a drive along 16th Avenue I noticed there are little green tents hung at regular intervals, which may be Gypsy Moth traps.)

Then we’d go back to the same traps to see how many of the little critters we’d caught.  In a whole lovely summer of chasing them, I never saw a single one.  But eventually one was found in Mission and some spraying took place there.

A memorable event took place when my partner and I stopped at a Hope business and asked the proprietor for directions on the map directing us as to where to hang the days traps.   At first the man was really friendly.  Then he lookUnknown-2ed intently at the map and at us, and asked in a suddenly sharp voice,…..”Who are you, and what are you doing here?”  So it quickly became very clear that he was furiously oimages-2pposed to the threat of having Bacillus thuringiensis (Bt) sprayed on his city. (Spraying had already been done once on Hope, he said, with really negative effects, and the populace were ready to bring out the shotguns.(slight exaggeration here,…..I think.))

We left with our lives intact, but his reaction gave me some serious doubts about my wonderful summer job. Is this Bacillus thuringiensis (Bt) spraying as harmless as we had  been led to believe?images-1PUPATION_5020053-pupae_000photo_emerge

I have really enjoyed looking for the right response, to give my friend, which at this point I don’t yet have.  But perhaps you can take a few minutes for this excellent documentary on Gypsy Moth.


One thing I can say with certainty to the young woman,… do not be at all quick to take part in on-line petitions.  Spend the time, if you possibly can, informing yourself and then call the appropriate government office or politician, or write them your own thoughtful questions or petition the authorities on your own behalf.  It’s too easy to hit a button and join the crowd’s petition of the day without having a clue about the topic.

Soren Kierkegaard, wrote,……. “The crowd is untruth.”
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no. 5.556

Bacillus thuringiensis

by W.S. Cranshaw* (7/14)

  • Bacillus thuringiensis (Bt) is a naturally occurring bacterial disease of insects. These bacteria are the active ingredient in some insecticides.
  • Bt insecticides are most commonly used against some leaf- and needle-feeding caterpillars. Recently, strains have been produced that affect certain fly larvae, such as mosquitoes, and larvae of leaf beetles.
  • Bt is considered safe to people and nontarget species, such as wildlife. Some formulations can be used on essentially all food crops.
  • Bt is used in agriculture as a liquid applied through overhead irrigation systems or in a granular form for control of European corn borer.

Bacillus thuringiensis (Bt) is an insecticide with unusual properties that make it useful for pest control in certain situations. Bt is a naturally occurring bacterium common in soils throughout the world. Several strains can infect and kill insects. Because of this property, Bt has been developed for insect control. At present, Bt is the only “microbial insecticide” in widespread use.
The insecticidal activity of Bt was first discovered in 1911. However, it was not commercially available until the 1950s. In recent years, there has been tremendous renewed interest in Bt. Several new products have been developed, largely because of the safety associated with Bt-based insecticides.


Unlike typical nerve-poison insecticides, Bt acts by producing proteins (delta-endotoxin, the “toxic crystal”) that reacts with the cells of the gut lining of susceptible insects. These Bt proteins paralyze the digestive system, and the infected insect stops feeding within hours. Bt-affected insects generally die from starvation, which can take several days.

Occasionally, the bacteria enter the insect’s blood and reproduce within the insect. However, in most insects it is the reaction of the protein crystal that is lethal to the insect. Even dead bacteria containing the proteins are effective insecticides.

The most commonly used strain of Bt (kurstaki strain) will kill only leaf- and needle-feeding caterpillars. In the past decade, Bt strains have been developed that control certain types of fly larvae (israelensis strain, or Bti). These are widely used against larvae of mosquitoes, black flies and fungus gnats.

More recently, strains have been developed with activity against some leaf beetles, such as the Colorado potato beetle and elm leaf beetle (san diego strain, tenebrionis strain). Among the various Bt strains, insecticidal activity is specific. That is, Bt strains developed for mosquito larvae do not affect caterpillars. Development of Bt products is an active area and many manufacturers produce a variety of products. Effectiveness of the various formulations may differ.


Bt is susceptible to degradation by sunlight. Most formulations persist on foliage less than a week following application. Some of the newer strains developed for leaf beetle control become ineffective in about 24 hours.

Manufacturers are experimenting with several techniques to increase its persistence. One involves inserting Bt toxic crystal genes into other species of bacteria that can better survive on leaf surfaces (e.g., the M-Trak formulation of san diego strain).

Bt-based products tend to have a shorter shelf life than other insecticides.Unlike most insecticides, Bt insecticides do not have a broad spectrum of activity, so they do not kill beneficial insects.Perhaps the major advantage is that Bt is essentially nontoxic to people, pets and wildlife.

The highly specific activity of Bt insecticides might limit their use on crops where problems with several pests occur, including nonsusceptible insects (aphids, grasshoppers, etc.). As strictly a stomach poison insecticide, Bt must be eaten to be effective, and application coverage must be thorough. This further limits its usefulness against pests that are susceptible to Bt but rarely have an opportunity to eat it in field use, such as codling moth or corn earworm that tunnel into plants. Additives (sticking or wetting agents) often are useful in a Bt application to improve performance, allowing it to cover and resist washing.

Since Bt does not kill rapidly, users may incorrectly assume that it is ineffective a day or two after treatment. This, however, is merely a perceptual problem, because Bt-affected insects eat little or nothing before they die.

Bt-based products tend to have a shorter shelf life than other insecticides. Manufacturers generally indicate reduced effectiveness after two to three years of storage. Liquid formulations are more perishable than dry formulations. Shelf life is greatest when storage conditions are cool, dry and out of direct sunlight.


The specific activity of Bt generally is considered highly beneficial. Unlike most insecticides, Bt insecticides do not have a broad spectrum of activity, so they do not kill beneficial insects. This includes the natural enemies of insects (predators and parasites), as well as beneficial pollinators, such as honeybees. Therefore, Bt integrates well with other natural controls. For example, in Colorado, Bt to control corn borers in field corn has been stimulated by its ability to often avoid later spider mite problems. Mite outbreaks commonly result following destruction of their natural enemies by less selective treatments.

Perhaps the major advantage is that Bt is essentially nontoxic to people, pets and wildlife. This high margin of safety recommends its use on food crops or in other sensitive sites where pesticide use can cause adverse effects.


The greatest use of Bt involves the kurstaki strain used as a spray to control caterpillars on vegetable crops. In addition, Bt is used in agriculture as a liquid applied through overhead irrigation systems or in a granular form for control of European corn borer. The treatments funnel down the corn whorl to where the feeding larvae occur.

Many formulations (but not all) are exempt from pesticide tolerance restrictions and may be used up to harvest on a wide variety of crops. This also makes Bt useful in applications where pesticide drift onto Gardens is likely to occur, such as treating trees and shrubs. The exceptional safety of Bt products also makes them useful where exposure to pesticides is likely during mixing and application.

To control mosquito larvae, formulations containing the israelensis strain are placed into the standing water of mosquito breeding sites. For these applications, Bt usually is formulated as granules or solid, slow-release rings or brickettes to increase persistence. Rates of use are determined by the size of the water body. Make applications shortly after insect eggs are expected to hatch, such as after flooding due to rain or irrigation. Bt persistence in water is longer than on sun-exposed leaf surfaces, but reapply if favorable mosquito breeding conditions last for several weeks. Although the israelensis strain is quite specific in its activity, some types of nonbiting midges, which serve as food for fish and wildlife, also are susceptible and may be affected.

Use of Bt (israelensis) for control of fungus gnat larvae involves drenching the soil. Bt applied for control of elm leaf beetle or Colorado potato beetle (san diego/tenebrionis strain) is sprayed onto leaves in a manner similar to the formulations used for caterpillars. Bt does not control shore flies, another common fly found in greenhouses.
1 Colorado State University Extension entomologist and professor, bioagricultural sciences and pest management. 11/99. Reviewed 2/09. 


Gypsy moth spraying over Surrey, Delta postponed by rain

Spraying will take place on Tuesday, weather permitting

CBC News Posted: Apr 27, 2015 9:43 AM PT Last Updated: Apr 27, 2015 9:43 AM PT

A European gypsy moth is shown caught in one of the Canadian Food Inspection Agency's pheromone traps in Surrey, B.C., the summer of 2014.

A European gypsy moth is shown caught in one of the Canadian Food Inspection Agency’s pheromone traps in Surrey, B.C., the summer of 2014. (B.C. Ministry of Forests)

(Note: CBC does not endorse and is not responsible for the content of external links.)

The B.C. Ministry of Forests has postponed the second round of aerial spraying over parts of Delta and Surrey targeting gypsy moths this morning because of the wet weather.

The ministry says it plans to spray the insecticide by low-flying helicopter on Tuesday morning instead, if the forecast allows. A third and final round of spraying is scheduled for May 11.

Gypsy moths are an invasive species that is known to damage a wide range of trees and other plants. The spray, called Foray 48B, contains a bacteria that kills gypsy moth caterpillars after they ingest it.

Some residents want the spraying cancelled completely, arguing the insecticide could hurt people. But the ministry says there is no evidence the spray is harmful to humans.

A friend sent these thoughts:…(I’ll leave his name off)

My manager’s car (lives in Surrey on Langley border) has been sprayed twice already in the last few weeks. He thought it was for mosquito control but perhaps it is for Gypsy Moth? Sticky stuff all over his car.

I agree with you, against signing online petitions.

My question is why bother? Do the moths recognize and respect borders between Surrey/Delta, and Langley, Burnaby, New Westminster, Richmond, Vancouver, etc.? Is this a waste of tax payer dollars for the perception of doing something?

Like so many “threats”, they land on USA soil, migrate to Canada, and then “require” non-tariff barriers to trade in order to “protect” USA industries. I expect if we do not spray, that is what we will face. BC ornamental nursery and forest products industries will suffer the consequences. For Canada this is Déjà vu, the definition of “Free Trade” we get to live by.

And another response:

According to a report I heard on CKNW, apparently Fraser Health is all over the place on the spraying — while saying it is safe for humans, they want people who have health concerns re: the spraying to go to hospital — how can it be both “safe”, and cause health concerns ?