Project reference: 2002-05
Identification of the Pheromone of the Defoliator Pseudocoremia suavis (Lepidoptera: Geometridae)
The most serious insect defoliation of pines and Douglas-fir in New Zealand has not been caused by an introduced species but, surprisingly, by the native looper Pseudocoremia suavis. This species had considerable outbreaks in the 1950ˇ¦s and 1960s in pine plantations in Canterbury (White 1974) and in Douglas-fir plantations in Kaingaroa Forest in the 1970s (Alma 1977). At the time, the massive defoliation caused in Canterbury even prompted aerial spraying with DDT to protect the trees. There have not been any more outbreaks in recent years, but a trapping survey conducted in early 2002 using live female P. suavis as lures found that the populations in Canterbury pine plantations are indeed still very high (Brockerhoff et al., forthcoming FHRC report), and further outbreaks cannot be ruled out.
Pheromones typically are an essential part of insect pest management programmes. The use of pheromones includes monitoring of populations with pheromone-baited traps and mass trapping, as well as more sophisticated methods such as lure and kill and mating disruption (Howse et al. 1998). Although the implementation of the recent trapping study with live females was successful, a massive rearing effort was required to provide fresh female moths in large numbers, which makes this method highly unpractical for operational work. Thus, the knowledge of the chemical composition of the pheromone of P. suavis would be highly desirable to facilitate the pheromone-based pest management methods mentioned above. We propose to identify the pheromone of P. suavis, using a number of standard procedures including gland extraction, GC-EAD, and GC-MS. Once known, the pheromone can be synthesised and made available for use in New Zealand forestry.