• De Boo, R.F.
  Canadian Forestry Service Department of the Environment
  
• Campbell, L.M.
  Canadian Forestry Service Department of the Environment
  
• Copeman, A.G.
  Canadian Forestry Service Department of the Environment
  

A technique for mechanically sorting defoliating insects from coniferous branch samples was evaluated experimentally for its potential in determining numerical indices of population densities as required for chemical control operations. The technique involves the utilization of a simple truck-mounted apparatus for the collection of target species at field sampling stations. Larvae of the spruce budworm (Choristoneura fumiferana and the jack-pine budworm (C. pinus pinus) were target species for evaluations in New Brunswick and Manitoba.

The technique showed a four-fold advantage over the conventional counting mill system when compared on the basis of time, staff and cost. Efficiency of recovery of larvae and accuracy of results were on a par with results obtained by visual examination of branch samples.