Most government ministries in British Columbia (BC) have published annual reports since the late 1800s. The annual reports issued by the BC Ministry of Agriculture record the progress of human endeavors to control agricultural pests and parasites.

The 1901, “Report of the Inspector of Fruit Pests” explains how to make Bordeaux mixture for the control of apple-scab and fungous diseases. This involves mixing a sulphate of copper solution with a solution of lime. The report then explains how to test the solution: 

“It is now necessary to determine whether the mixture is perfect -that is, if it will be safe to apply to tender foliage. To accomplish this, two simple tests may be used. First, insert the blade of a penknife in the mixture, allowing it to remain there for at least one minute. If metallic copper forms on the blade, or, in other words, if the polished surface of the steel assumes the colour of copper plate, the mixture is unsafe and more lime must be added. If, on the other hand, the blade of the knife remains unchanged, it is safe to conclude that the mixture is as perfect as can be made. As an additional test however, some of the mixture may be poured into and old plate or saucer, and while held between the eyes and the light, the breath should be gently blown upon the liquid for at least half a minute. If the mixture is properly made, a thin pellicle, looking like oil on water, will begin to form on the surface of the liquid. If no pellicle forms, more milk of lime should be added.”

The “Annual and Quarterly Meetings of the British Columbia Fruit Growers Association”, published in 1909, reveals that fruit growers were losing faith in Bordeaux mixture.

“Great chaos exists in our knowledge of and experience with Bordeaux mixture. This is well illustrated by the fact that eighty-seven experiment station bulletins give fifty different formulas for Bordeaux, running all the way from two pounds of vitriol and two pounds of lime, to twelve and half pounds of vitriol and twelve and a half pounds of lime, in fifty gallons of water. Twelve of these different formulas are in bulletins dated 1908. Five bulletins insist that the vitriol should be poured into the lime; twenty-two, that the lime should be poured into the vitriol; seven that the two should be poured together into a third vessel; two, that first a bucket of one, and then a bucket of the other should be poured in; eight, in a non-committal way, say to mix them, and one, having tested the various ways, shows that they are all equally good (or all equally bad)."


The 1905 edition of “ABC of Bee Culture” mentions a strange ailment in honeybees that is blamed on Bordeaux: 

“Thousands of bees will be found on the grass and sidewalks minus their abdomens. Others not dismembered will apparently be suffering excruciating pain....”
“The United States Chemist, on examining the contents of the bowels of some bees I sent him, found traces of copper poisoning,  showing the bees were suffering because of having taken the nectar that was mixed with the Bordeaux used for killing the insect pests on the trees; and the suffering was so great that, in struggling at the source of pain, they tore themselves asunder....”

The 1928 BC Provincial Apiarist report mentions a new problem:

“Several authenticated instances of poisoning of bees were reported in the Okanagan in districts where arsenate of lead had been used in spraying solutions in the orchard.....If some strong-smelling substance, such as crude carbolic or creosote, was added to the spray solution, just sufficient to give it an odor obnoxious to bees, this would act as a deterrent, and cause them to avoid the poison when in search of moisture.”

Then, from the BC Provincial Apiarist report of 1944:

“Bee-keepers and fruit-growers alike were particularly interested in the results of the repellent spray tests conducted by the Horticulture Branch of the Department of Agriculture. These tests were started in 1942 and based on a formula recommended by the Department of Conservation, State  of Massachusetts, being a mixture of creosote with the usual lead arsenate used for spraying fruit-trees for codling-moth....
The formula with oil of creosote was given to several orchardists who were also bee-keepers, to be tried out under the usual growers’ conditions. In every case a burning of foliage was reported ranging from slight to severe. This seems to have been caused by the incomplete mixing of the creosote. No bee loss was reported in any case.
In 1944, the officials conducting the tests decided to abandon the use of oil of creosote as being unsafe for use by growers and to continue with the more stable crude carbolic acid as a repellent...”

This ongoing problem with lead arsenate poisoning of bees was solved by 1947. The BC Provincial Apiarist annual report for that year states:

“Loss From Spray Poison”
“I am glad to report that no serious loss has been reported this year, due, no doubt, to the recommendations of the various authorities advising that arsenical sprays be abandoned and various forms of DDT be used. If this continues, the orchard areas will again be real districts for honey production. In fact, many of the beekeepers did not move their apiaries out of the orchards and report no material loss from poison, and in most cases reported a bumper crop of honey.”

 DDT use lasted until 1969 in British Columbia. That year the Department of Agriculture annual report stated:

“The use of a number of well-known pesticides was considerably reduced in British Columbia when these were removed from the official Departmental recommendations. These included DDT, chlordane, heptachlor, aldrin, dieldrin and endrin...”

This history of pesticide use in British Columbia reminds me a bit of the current discussion about using oxalic acid vapours in beehives;  eg, ‘ Do you know what’s going on?’ ‘No, I don’t know what’s going on.’ ‘O.K., I think I know what’s going on.’ etc. 

I certainly appreciate all the research by various individuals to determine how best to use oxalic acid to control varroa mites. But our track record thus far indicates it takes at least twenty years of practical use and research to determine if a new pesticide is safe to use. Here's hoping OAV is one of them.  Ted      

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