Codling Moths, like varroa mites, were imported into North America. And like varroa, the moth is difficult to kill without damaging its host (fruit). 

“Mature codling moth larvae overwinter in silken cocoons in protected sites on the tree (under loose bark, in cracks and crevices), in the soil or in wooden materials under or beside infested trees (bins, ladders, poles, buildings, large prunings). Larvae pupate in the spring and adults usually begin to emerge in early May and continue emerging until late June (mid-July in cooler areas), depending on temperature. Mating and egg-laying occur when twilight temperatures are above15°C. Females lay eggs on fruit or on leaves near fruit. Larvae usually wander over the fruit surface before cutting through the skin and boring deeply into the fruit. Mature larvae leave the fruit to pupate in protected sites on and off the tree as described above.” (B.C. Ministry of Agriculture)

The first effective pesticide used to control codling moth was lead arsenate. It was originally thought that spraying fruit blossoms was best as this entrapped the poison in the calyx; it was assumed most caterpillars entered the fruit through the calyx. However, it gradually became apparent that caterpillars had no preferred entry point so the whole fruit had to be covered with poison.  
         
“From 1900 to 1920, in the USA the average number of arsenical-type sprays/season for the control of codling moth was 1 - 3, in 1920's 4-5, in 1930's 4-8 and in 1940's 6 -10. The increase in application frequency was due to development of resistance against lead arsenate, the primary agent used for the control of codling moth” (B.A. Croft and H. W. Riedl. 1991. Chemical control and resistance to pesticides of the codling moth, pp. 371 - 387. In L.P.S. van der Geest and H.H. Evenhuis (eds.), Tortricid pest: their biology, natural enemies and control. Elsvier, Amsterdam).

In 1946, DDT was found to control codling moth and it replaced arsenic based pesticides as the preferred insecticide for use in orchards.

As evidence of the damaging environmental side-effects of DDT began to accumulate, growers were forced to switch to using phosphates and carbamates. When these chemicals were in turn linked to environmental poisoning, their use was also restricted as neonicotinoids became available.
 
Bees and beekeepers suffered during this evolution of pesticide use. Arsenic (lead arsenate) proved to be extremely toxic to bees. DDT was less toxic but still toxic.
 
“Severity (of bee losses) further increased to the point of disaster for many beekeepers in the 1960’s when the use of DDT and some other chlorinated hydrocarbons was decreased sharply by legislation as a reaction to public concern, and they were replaced in the majority of instances by the more toxic phosphates and carbamates.... Wearne et al. (1970) and Barnes (1972) concluded that the major problem confronting the beekeeping industry was bee losses due to pesticides...All indications point to an annual loss by the industry in the neighbourhood of ten percent by pesticides alone ” (Insect Pollination of Cultivated Crop Plants, USA Department of Agriculture Handbook No. 496 by S.E. McGregor, 1976)

 It seems that every pesticide approved for use against codling moth has eventually been outlawed as their harmful side-effects become known. As always, only time will tell if neonicotinoids are truly safe. 

Scientists now encourage caution when using chemicals to control codling moth (http://www.agf.gov.bc.ca/cropprot/tfipm/codlingmoth.htm ) and recommend using a variety of physical means to help control this pest.

Given all this I am surprised how much time and energy is spent on Bee-l criticising people like Dee Lusby. I don’t understand how Dee is part of the problem – the problem being that bees are sensitive to the toxic effects of pesticides, mites are adept at developing resistance to pesticides, beeswax is known to absorb pesticides, pesticides have been known to decay into products that are more toxic than the original pesticide, pesticides in beeswax may interact to create products toxic to bees etc. etc. etc. I see Dee as someone who is trying to find solutions to this problem.
    
Experience has shown the dangers of relying too heavily on pesticides. I think we should encourage anyone who is trying to find alternatives. 

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