Photos from the WFIWC Archives:
Equipment and Methodology

Mark McGregor holding 1 dram vial containing 300 mg MCH. When placed in perforated canisters on stakes at 10- by 10-ft spacing, elution of neat MCH reduced Douglas-fir beetle attacks in downed trees by 95.6% during 1972 tests. (M. Furniss photo)

12- by 12-inch bark samples were removed from test trees to evaluate results. This sample was typical of most trees treated with the optimum elution rate and spacing. (M. Furniss photo)

As described separately (view initial pheromone tests or MCH discovery; also view later field studies), during 1971 tests I discovered that methylcyclohexenone (MCH), provided by Julius Rudinsky, repressed the attraction of the Douglas-fir beetle aggregative pheromone, frontalin and host volatiles. In 1972, I organized a cooperative test to determine the optimum elution rate of neat MCH for preventing infestation of downed Douglas-fir (Furniss et al. 1974). Historically, "outbreaks" of the beetle result from its population increasing in windfelled or snow-broken trees that lack host resistance. Ten treatments were replicated at locations in Idaho, Oregon and Washington. These treatments were 3 elution rates times 3 spacings around felled trees, and a control. I devised the dispensers and determined elution rates in the laboratory beforehand. For the purpose of bracketing the optimum rate, I varied elution rate 1,000 fold from least to greatest, and from one dispenser per tree to dispensers placed 10-ft and 30-ft apart on plots 30- by 120-ft encompassing each tree.

Felling the trees and setting up the plots and treatments extended from March into early April while the ground was covered with deep snow to be sure that the test was in place before beetles emerged. It was a big job requiring commitment and energy that I now can only marvel at. The gist of all this effort is that we did, indeed, bracket the optimum elution rate, which was 0.06-1.3 grams/acre per day. Now, we were posed to begin the development and testing of a controlled-release formulation of MCH and thereafter an aerial application method. This would proceed over the next several years with limited funds and the assistance of others including Mark McGregor of Forest Service Region 1, Missoula, who participated throughout that time. -- Malcolm Furniss

Reference Cited:
 
Furniss, M. M., G. E. Daterman, L. N. Kline, M. D. McGregor, G. C. Trostle, L. F. Pettinger, and J. A. Rudinsky. 1974. Effectiveness of the Douglas-fir beetle antiaggregating pheromone, methylcyclohexenone, at three concentrations and spacings around felled host trees. Can. Entomol. 106:381-392.

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