The monoterpene α-pinene, a major component of the terpene composition of Pinus spp., has been reported to act as a host-produced kairomone for a variety of bark beetle species, including the mountain pine beetle, Dendroctonusponderosae Hopkins. However, our experiments indicate that α-pinene autoxidizes under normal temperature and atmospheric conditions to form significant quantities of trans-verbenol, an aggregation pheromone for many species of bark beetles. The quantities of α-pinene present in the resin that can flow from small wounds in pine trees appear to be sufficient to produce trans-verbenol at rates similar to those by female beetles that are actively synthesizing the compound.trans-Verbenol can then autoxidize rapidly to form verbenone, with the content of this compound reaching 8% within 13 weeks of exposure to air. Verbenone is often used by scolytids as an antiaggregation pheromone. Approximately 1.9% of the trans-verbenol and 2.7% of the verbenone found in Porapak Q aerations of phloem with boring spruce beetle, Dendroctonusrufipennis (Kirby), females, as well as 0.8% of the trans-verbenol and 0.8% of the verbenone found in aerations of phloem with boring D. ponderosae females, was due to the autoxidation of α-pinene and (or) the release of oxygenated compounds found in the phloem before bark beetle attack. The natural interconversion of α-pinene, trans-verbenol, and verbenone under ambient conditions suggests that many experiments involving the behavioral activity of these compounds require re-evaluation.

This study investigated the inßuence of different humidity levels on percentage of infection by Beauveria bassiana (Balsamo) Vuillemin (Hyphomycetes) (Botanigard EmulsiÞable Suspension formulation) on greenhouse insect and mite pests, and their commercially available biological control agents. The target insect and mite species were sprayed with B. bassiana and evaluated in petri dish trials under controlled environment conditions, on cucumber leaves under greenhouse crop conditions, and under fully sprayed greenhouse conditions. Results of this study showed that in petri dish trials, a humidity of 97.5% RH resulted in signiÞcantly higher percentage of infection (60 Ð 88.8%), while at 75 and 80% RH only 15.3Ð 43.9% of the pest insects were infected. On leaf surfaces, the differences in ambient humidity did not cause as great of variations in percentage of infection as in the petri dish trials. Increasing greenhouse humidity by 15% RH caused an increase of 17Ð25% in percentage of infection. Under high humidity conditions, whole greenhouse sprays with B. bassiana successfully suppressed populations of Frankliniella occidentalis (Pergande) and Trialeurodes vaporariorum (Westwood). Tetranychus urticae Koch was not infected by B. bassiana at sig-niÞcant levels in any of the trials. Predatory mites can be used with B. bassiana, while adult Orius insidiosus (Say), Aphidius colemani Viereck, and Dacnusa sibirica Telenga are not recommended to be introduced during the application of B. bassiana. Encarsia formosa Gahan, Eretmocerus eremicus (Rose and Zolnerowich), and Aphidoletes aphidimyza (Rondani) need to be used with caution when B. bassiana is applied.

A variety of symbionts associated with bark beetles are capable of producing compounds that are used as pheromones by their hosts. We report that two yeasts associated withDendroctonus ponderosae Hopkins,Hansenula capsulata Wickerham, andPichiapinus (Hoist) Phaff, are capable of convertingcis- andtrans-verbenol efficiently into verbenone.trans-Verbenol, which is produced by femaleD. ponderosae, acts as an aggregation pheromone for this scolytid, while verbenone, which other studies have indicated that microbe-reducedD. ponderosae are incapable of producing, acts as an antiaggregation pheromone.D. ponderosae appears to rely primarily on microbial symbionts for terminating aggregation and mass attack on individual host trees.

Pitfall traps were used in field tests to evaluate the relative attractiveness of red pine, Pinus resinosa Aiton, volatiles, turpentine, ethanol, and combinations thereof to adult Hylobius radicis Buchanan and Pachylobius picivorus (Germar). Traps baited with a combination of ethanol and turpentine caught significantly more of both species of weevils than any other bait tested. Only overwintered H. radicis were attracted to the baits. The sex ratio for weevils captured in all traps was 9.1:1 females/males for H. radicis and 1.7:1 for P. picivorus. A significant relationship was observed between numbers of H. radicis captured in pitfall traps placed in plots of Scotch pine, Pinus sylvestris L., and percentage incidence of foliar symptoms.

Mountain pine beetles,Dendroctonus ponderosae Hopkins, and California five-spined ips,Ips paraconfusus Lanier, were reared axenically from surface-sterilized eggs on aseptic pine phloem. After 24 hr in host logs, axenip femaleD. ponderosae and maleI. paraconfusus produced the aggregation pheromones,trans-verbenol (D. ponderosae), and ipsenol and ipsdienol (I. paraconfusus). Emergent, axenically reared maleD. ponderosae contained normal amounts of the pheromoneexo-brevicomin. Axenic femaleD. ponderosae treated with juvenile hormone or exposed to vapors of α-pinene, produced the pheromonetrans-verbenol. By 25-35 days after eclosion, axenic females exposed to α-pinene vapors produced over six times as muchtrans-verbenol as wild females, suggesting that while microorganisms in wild females may producetrans-verbenol, they may also inhibit production of the pheromone or use it as a substrate.

Soybean aphid (Aphis glycines Matsumura) is a native pest of soybean [Glycine max (L.) Merr.] in eastern Asia and was detected on soybeans in North America in 2000. In 2004, the soybean cultivar Dowling was described to be resistant to soybean aphids with the Rag1 gene for resistance. In 2006, a virulent biotype of soybean aphid in Ohio was reported to proliferate on soybeans with the Rag1 gene. The objective was to survey the occurrence of virulent aphid populations on soybean indicator lines across geographies and years. Nine soybean lines were identified on the basis of their degree of aphid resistance and their importance in breeding programs. Naturally occurring soybean aphid populations were collected in 10 states (Kansas, Illinois, Indiana, Iowa, Michigan, Minnesota, North Dakota, Ohio, South Dakota, and Wisconsin) and the Canadian province of Ontario. The reproductive capacity of field‐collected soybean aphid populations was tested on soybean lines; growth rates were compared in no‐choice field cages at each geographic region across 3 yr. The occurrence of soybean aphid biotypes was highly variable from year to year and across environments. The frequency of Biotypes 2, 3, and 4 was 54, 18, and 7%, respectively, from the 28 soybean aphid populations collected across 3 yr and 11 environments. Plant introduction (PI) 567598B, a natural gene pyramid of rag1c and rag4, had lowest frequency of soybean aphid colonization (18%). Several factors may have contributed to the variability, including genetic diversity of soybean aphids, parthenogenicity, abundance of the overwintering host buckthorn (Rhamnus spp.), and migratory patterns of soybean aphids across the landscape.

Dendroctonus ponderosae Hopkins andIps paraconfusus Lanier of both sexes produced most of their complement of terpene alcohols at normal to elevated levels in the absence of readily culturable microorganisms. However, there was some evidence that microbial involvement may be required by maleI. paraconfusus to produce ipsenol and ipsdienol at normal levels. Increased levels of certain terpene alcohols found in axenically reared or streptomycin-fed beetles suggest that symbiotic microorganisms may be responsible for breaking down pheromones and other terpene alcohols. There was also evidence for microbial involvement in the production of the antiaggregation pheromone verbenone inD. ponderosae. This compound was not produced in quantifiable levels by axenically reared or streptomycin-fed beetles exposed to α-pinene as vapors or through feeding, but was found in wildD. ponderosae exposed to α-pinene through feeding on bolts of lodgepole pine,Pinus contorta var.latifolia Engelmann.

Cutting schedules affect forage yield, nutritive value, and persistence but few studies have recently assessed the effect of intensive cutting schedules on alfalfa (Medicago sativa L.)-based mixtures. We determined the effects of (a) cutting at early bud vs. early bloom of alfalfa, (b) a fall cut, (c) alfalfa-grass mixture vs. pure alfalfa, (d) one vs. two grasses, and (e) tall fescue (Schedonorus arundinacea [Schreb.] Dumort.) vs. timothy (Phleum pratense L.) in an experiment over four post-seeding years at four sites with four cutting schedules on four alfalfa-based mixtures. Cutting alfalfa at early bud rather than early bloom reduced annual forage dry matter (DM) yield by 2.03 Mg ha −1 and alfalfa contribution to DM yield by 17 percentage units, increased forage total digestible nutrient (TDN) concentration by 44 g kg −1 DM but did not increase estimated annual milk production per hectare. A fall cut did not improve annual forage DM yield and estimated annual milk production per hectare but reduced alfalfa contribution to DM yield. Pure alfalfa resulted in 1.09 Mg DM ha −1 less annual forage DM yield than alfalfa grown with one or two grasses. Two forage grasses with alfalfa compared with just one grass had no effect on forage DM yield and estimated annual milk production per hectare. The response of forage DM yield and estimated annual milk production per hectare to timothy or tall fescue with alfalfa varied with site but forage TDN concentration and alfalfa contribution to DM yield were generally greater with timothy than tall fescue.Abbreviations: ADF, acid detergent fiber; aNDF, neutral detergent fiber assayed with a heat-stable amylase and sodium sulfite; CP, crude protein; DM, dry matter; GDD, growing degree-days calculated using a 5 • C basis; NDFd, in vitro neutral detergent fiber digestibility; PLS, pure live seed basis; TDN, total digestible nutrients; VNIRS, visible and near-infrared reflectance spectroscopy.