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Development of effective trapping tools for forest pests and evaluating the key components of these tools is necessary to locate early‐stage infestations and develop management responses to them. Agrilus planipennis Fairmaire (emerald ash borer) is an introduced pest of ash (Fraxinus spp. L.) in North America. The effectiveness of different trap and lure combinations were tested in areas with low and high density populations of A. planipennis. At low density sites, purple prism traps outperformed green traps and girdled ash trap trees in capture rates (adults per day) and rates of detection of A. planipennis. Also, manuka oil lures, used as a standard lure in a national survey programme, captured higher rates of A. planipennis than did previous standards of girdled ash trap trees. There was no logistic relationship between the detection of A. planipennis on a trap and the diameter of the ash tree from which the trap was suspended, possibly because of the use of artificial lures with these traps. There was also no difference in the mean number of A. lanipennis captured per day between ash species and between vigour rating of ash associated with the traps. However, traps placed in open grown and dominant trees captured more beetles than traps placed in lower canopy class trees. At sites defined as low and high density, there was no difference in the larval density per cm3 of phloem. This suggests that exposure time to A. planipennis has been shorter at those low density sites. By exploiting the trap and tree characteristics that improve A. planipennis capture rates and detection efficacy, there can be future improvement in management of this pest. If detection can occur before infested ash trees exhibit signs and symptoms, there may be a potential for reducing the mortality of ash within stands.

Evidence is presented for transcriptional regulation of de novo pheromone biosynthesis in Ips spp. bark beetles, but the comparative biochemical and molecular approach reveals a dichotomy between species in the pini and grandicollis subgeneric groups. Radiotracer studies with 14C-acetate demonstrate that feeding on host phloem stimulates biosynthesis in males of three Ips spp. However, treatment with juvenile hormone III (JH III) stimulates biosynthesis only in Ips pini. Thus, two species in the grandicollis subgeneric group (I. grandicollis and I. paraconfusus) appear to have a different mode of regulation related to JH III than does I. pini. Between 16 and 20 hr after feeding has commenced, pheromone production, as measured by accumulation in abdominal tissue, is stimulated about 150- (I. pini) and 350-times (I. paraconfusus) above the control level of 1-10 ng/male measured at 0 hr. Treatment with JH III results in accumulation in I. pini that is 3-4 times more than in phloem-fed males, whereas the identical treatment results in only weak accumulation in I. paraconfusus (45-times less than phloem-fed males). Comparative studies of gene expression and enzyme activity related to biosynthesis also support different modes of JH III-related regulation in I. pini and I. paraconfusus. In males of both species, feeding on host phloem results in increased transcript abundance and increased activity for the key de novo isoprenoid pathway enzyme 3-hydroxy-3-methylglutaryl-CoA reductase (HMG-R). However, while JH III treatment results in comparable maximal increases in HMG-R transcript levels in both species (similar to feeding), the activity of HMG-R in crude extracts from JH III-treated male I. paraconfusus is low in comparison with male I. pini. Hypothetical explanations for the interspecific dichotomy in the regulation of pheromone biosynthesis include a second hormone or factor in grandicollis group species that functions either alone or with JH III; in both cases acting after HMG-R has been transcribed.