Photos from the WFIWC Archives:
Equipment and Methodology

LeRoy Kline (left), Malcolm Furniss and Julius Rudinsky with sticky screen trap used to test Douglas-fir beetle pheromones, Mount Hood N.F., Oregon. 1971; M. Furniss photo.

MCH and other pheromones and host-derived synergists were eluted from ½ dram vials inside aluminum film canisters having perforated bottoms; M. Furniss photo.

M. Furniss applying pheromone dispenser to live Douglas-fir in Idaho, 1971; M. Furniss photo.

In 1971, Julius Rudinsky (1917-1980) of Oregon State University had several candidate Douglas-fir beetle pheromones that he wished to have field tested. By coincidence, LeRoy Kline ... then the Oregon Dept. of Forestry forest entomologist at Salem ... had been my summer assistant while he was a graduate student of Julius. We worked out an arrangement by which I would test them in Idaho for possible differences in response compared to replicated tests by Kline and Rudinsky in Oregon. Two methods were used: 1. Various treatments applied to sticky traps to catch responding beetles, and 2. Treatments applied to live Douglas-fir. Julius did not wish to identify one of the pheromones and designated it as GLC "Peak 5." However, he characterized it as an attractant, thus I expected it to elicit Douglas fir beetle attacks when accompanying known attractants such as frontalin and synergists in host resin such as alpha pinene. Well, in a sense, this turned out to be the most unbiased test imaginable...in retrospect.

The test was conducted at the Boise Basin Experimental Forest near Idaho City in spring 1971, assisted by R.F. Schmitz of my research project at Moscow. We monitored the traps daily and rotated the treatments randomly among the trap locations. We also visually examined treated live trees for tell-tale frass. Very early into the test, I observed a remarkable result! The treatments involving Peak 5 were not attracting beetles; instead, it was obvious that it profoundly masked (nullified) the attraction of all previously demonstrated attractive treatments.

Also, about this time, I learned that methylcyclohexenone (MCH) had been identified from the beetle by GLC. I called Julius and announced the results that we were observing and inferred that Peak 5 was probably MCH. He confirmed that but felt that the antiaggegative (masking) effect was due to high concentration. That was never evident during subsequent research and development of MCH, but I am not sure whether he ever came to that view. To me, it seemed that it would diffuse area-wide to less concentration and at some distance it would result in trees being attacked. This never happened with MCH but it did with frontalin, for example, always resulting in surrounding trees being attacked.

Anyway, thanks to Julius, this remarkable antiaggregative pheromone became available to me and I set about with the meager resources of my project and assistance of several cooperators (foremost who were Mark McGregor and Ladd Livingston) to test and develop it for managing populations of the Douglas-fir beetle. This will be illustrated subsequently (view elution studies or field tests; also view earlier initial pheromone tests). -- Malcolm Furniss

References Cited
 
Furniss, M. M., L. N. Kline, R. F. Schmitz, and J. A. Rudinsky. 1972. Tests of three pheromones to induce or disrupt aggregation of Douglas-fir beetles (Coleoptera: Scolytidae) on live trees. Ann. Entomol. Soc. Am. 65:1227-1232.
 
Rudinsky, J. A., M. M. Furniss, L. N. Kline, and R. F. Schmitz. 1972. Attraction and repression of Dendroctonus pseudotsugae (Coleoptera: Scolytidae) by three synthetic pheromones in traps in Oregon and Idaho. Can. Entomol. 104:815-822.

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