Western pine shoot borer

Table I. Efficacy of mating disruption for controlling western pine shoot borer in various field trials. (1980 data from personal communication with Dr. D. Overhulser, Weyerhaeuser Co., Centralia, Wash.).

For perspective, however, we must also consider the successful disruption treatments that have resulted from placement of relatively few releasers at wide spacings. Farkas et al. (10) reported disruption of cabbage looper, Trichoplusia ni (Hubner), with releasers spaced at up to 400 m. Hand applied releasers placed at intervals of 5-10 m and emitting ca. 3.5-14.0 g pheromone/ha/season have been successful in reducing damage caused by western pine shoot borer (5). 

In a 1981 study on western pine shoot borer, three sets of traps baited with synthetic pheromone in controlled release PVC (polyvinyl chloride) pellets (12) were placed in ponderosa pine plantations (16 or more ha in size), treated with (a) Health Chemicals Hereon laminated flakes at some 20,000 flakes/ha with a pheromone release capacity of 10 g/ha/season (b) strips of Hereon laminated plastic (30 x 2 cm) at 25 strips/ha stapled on trees at 20 m intervals with a pheromone release capacity of 5 g/ha/season and, (c) an untreated check plot. The Pherocon II adhesive traps were baited with PVC pellets at five different bait strengths of 0.001%, 0.01%, 0.1%, 1.0%, and 10% pheromone by weight. Each of these baits was replicated seven times in each disruption treatment for a total of 35 traps per plantation and 105 overall. The traps were placed in lines of five with each bait concentration represented once in each line. The positions of the traps were randomized by bait concentration within each line, and traps were spaced at least 20 m apart. All traps were left in place through 4-weeks of the shoot borer s seasonal flight. 

Figure 1. Response of western pine shoot borer males to pheromone-baited traps in plots treated with different mating-disruption formulations and an untreated check plot. Key check (Q) 10 g pheromone in 20,000 flakes/ha (ffl) and 5 g pheromone in 25 strips/ha (ffl...

Table III. Capture of western pine shoot borer males by traps containing pheromone-baits of different strengths and placed in plots treated for mating disruption.

The western pine shoot borer work dates only from 1976. We have a tentative structural identification, and using that material on very small scale Vio acre) plots, were successful in demonstrating disruption of pheromone communication. We have plans to expand this effort in... 

---