Jl. Hayes et Bl. Strom, 4-ALLYLANISOLE AS AN INHIBITOR OF BARK BEETLE (COLEOPTERA, SCOLYTIDAE) AGGREGATION, Journal of economic entomology, 87(6), 1994, pp. 1586-1594
To assess the extent of inhibitory activity of the host compound 4-all
ylanisole, we conducted field studies with three scolytid species. The
se species are geographically widespread and economically important. T
rials were completed with Dendroctonus brevicomis LeConte (California)
, D. ponderosae Hopkins (Oregon), and Ips pini (Say) (Wisconsin) by us
ing multiple-funnel traps with appropriate pheromone-based attractants
. With the Dendroctonus species, the effects of 4-allylanisole were co
mpared with verbenone, an aggregation inhibitor produced by beetles th
emselves. We also determined effects of the treatments on the most abu
ndant coleopterous predators in each trial. Inhibition of bark beetle
aggregation behavior by 4-allylanisole was demonstrated for D. pondero
sae (Oregon) and I. pini (Wisconsin). In Oregon, 4-allylanisole reduce
d the catch of D. ponderosae at attractant-baited traps by 77%, wherea
s verbenone reduced the catch by 91% compared with attractant alone. A
lthough both reductions were significant, the effect of verbenone was
significantly greater than that of 4-allylanisole. In Wisconsin, addit
ion of 4-allylanisole to attractant-baited traps resulted in a signifi
cant reduction (43%) in numbers of I. pini caught, compared with attra
ctant alone. In the California trials, mean trap catches of D. brevico
mis were reduced by both 4-allylanisole (35%) and verbenone (27%) comp
ared with attractant alone, but neither reduction was significant. Sex
ratios of target scolytids were not affected by inhibitory treatments
in any trial. The predator Temnochila chlorodia (Mannerheim) (Coleopt
era: Trogositidae) was not affected by 4-allylanisole in California; h
owever, verbenone significantly reduced the number caught. Although ca
ptures were low, numbers of T. chlorodia caught by traps containing 4-
allylanisole in Oregon were significantly higher than those containing
verbenone or attractant alone (numbers in verbenone and attractant tr
aps were not significantly different). Numbers of the predatory beetle
s counted in Wisconsin-Thanasimus dubius (F.) (Coleoptera: Cleridae),
Platysoma parallelum Say (Coleoptera: Histeridae), and P. (Cylistix) c
ylindrica (Paykull) (Coleoptera: Histeridae)-were not affected by elut
ion of 4-allylanisole with the attractant. Implications of these resul
ts for protection of individual trees and management of bark beetle po
pulations are discussed.