Sketch of location of sample plots on Long Island used in experimental field test of Bacillus thuringiensis for western hemlock looper control. Naselle, Washington.
Photo by: Wally C. Guy and V.M. Carolin Date: July 19, 1963
Credit: USDA Forest Service, Pacific Northwest Region, State and Private Forestry, Forest Health Protection. Collection: Portland Station Collection; La Grande, Oregon Image: PS-2813
For more information about this field test see: archive.org/details/CAT92272778 Carolin, V.M. and C.G. Thompson. 1967. Field testing Bacillus thuringiensis for control of western hemlock looper. Research Paper PNW-38. Portland, OR: USDA Forest Service, Pacific Northwest Forest and Range Experiment Station. 26 p.