ENANTIOMERIC COMPOSITION AND RELEASE RATES OF exo-BREVICOMIN INFLUENCE AGGREGATION OF THE WESTERN BALSAM BARK BEETLE, DRYOCOETES CONFUSUS SWAINE (COLEOPTERA: SCOLYTIDAE)

1995 ◽  
Vol 127 (4) ◽  
pp. 449-456 ◽  
Author(s):  
Arthur J. Stock ◽  
J.H. Borden ◽  
T.L. Pratt ◽  
H.D. Pierce ◽  
B.D. Johnston
Keyword(s):  
Bark Beetle ◽  
Field Experiments ◽  
Enantiomeric Composition ◽  
Release Rates ◽  
Dryocoetes Confusus ◽  
Better Than

AbstractField experiments demonstrated that the western balsam bark beetle, Dryocoetes confusus, responded best to multiple-funnel traps baited with mixtures of (+)- and (−)-exo-brevicomin. (±)-exo-Brevicomin released at 0.8 mg per 24 h performed as well as or better than release rates of from 0.2 to 1.0 mg per 24 h in terms of the number of baited trees which were mass attacked (80%), average attack density, and average number of trees attacked within a 10-m radius of baited trees. Baiting more than one tree in a spot resulted in an intensification of attack on baited trees and increased the number of trees attacked within 10 m of each spot.

SECONDARY ATTRACTION IN THE WESTERN BALSAM BARK BEETLE, DRYOCOETES CONFUSUS (COLEOPTERA: SCOLYTIDAE)

1983 ◽  
Vol 115 (5) ◽  
pp. 539-550 ◽  
Author(s):  
A. J. Stock ◽  
J. H. Borden
Keyword(s):  
Bark Beetle ◽  
Field Experiments ◽  
Abies Lasiocarpa ◽  
Extraction Techniques ◽  
Dryocoetes Confusus ◽  
Male Attractant ◽  
Antiaggregation Pheromone ◽  
Primary Attraction ◽  
Laboratory Bioassays ◽  
Secondary Attraction

AbstractEvidence for secondary attraction in the western balsam bark beetle, Dryocoetes confusus Swaine, was obtained in laboratory bioassays and field experiments. Both sexes showed positive responses to volatiles of the host tree, Abies lasiocarpa (Hook.) Nutt., indicating that primary attraction is probably important in host selection by this species. Male beetles initiated attack and within 6 h produced an aggregation pheromone(s), which was present in frass and in pentane extracts of the abdomens of males excised from logs. Both sexes responded to the pheromone. Abdominal extract of unmated males which had bored into host bark for 14 days was still attractive. Pheromone production was induced by exposing males to host resin volatiles. Mating had no effect on male attractiveness, but induced females to produce an antiaggregation pheromone which, in laboratory bioassays, at least partially inhibited response to male attractant. The attractive volatiles from male-infested logs were successfully captured on Porapak Q®. The development of laboratory bioassay and pheromone extraction techniques indicates that a pheromone isolation program is feasible.

ENDO-BREVICOMIN: AN ANTIAGGREGATION PHEROMONE FOR THE WESTERN BALSAM BARK BEETLE, DRYOCOETES CONFUSUS SWAINE (COLEOPTERA: SCOLYTIDAE)

1990 ◽  
Vol 122 (5) ◽  
pp. 935-940 ◽  
Author(s):  
A.J. Stock ◽  
J.H. Borden ◽  
T.L. Pratt ◽  
H.D. Pierce ◽  
B.D. Johnston
Keyword(s):  
Bark Beetle ◽  
Aggregation Pheromone ◽  
Field Experiments ◽  
Field Tests ◽  
Abies Lasiocarpa ◽  
Subalpine Fir ◽  
Dryocoetes Confusus ◽  
Antiaggregation Pheromone ◽  
High Hazard ◽  
Laboratory Bioassays

AbstractLaboratory bioassays and field tests demonstrated that the (+) enantiomer of endo-brevicomin is an antiaggregation pheromone for the western balsam bark beetle, Dryocoetes confusus Swaine. (+)-endo-Brevicomin significantly reduced the response of beetles of both sexes to the aggregation pheromone exo-brevicomin in laboratory bioassays and in field experiments using multiple-funnel traps. It also prevented attack on subalpine fir, Abies lasiocarpa (Hook) Nutt., trees baited with exo-brevicomin. The (−) enantiomer of endo-brevicomin was inactive. These results suggest that (+) or (±)-endo-brevicomin has potential for protecting selected trees from attack, or suppressing western balsam bark beetle activity in high hazard or infested stands.

Semiochemicals produced by western balsam bark beetle,Dryocoetes confusus Swaine (Coleoptera: Scolytidae)

1987 ◽  
Vol 13 (4) ◽  
pp. 823-836 ◽  
Author(s):  
J. H. Borden ◽  
A. M. Pierce ◽  
H. D. Pierce ◽  
L. J. Chong ◽  
A. J. Stock ◽  
...  
Keyword(s):  
Bark Beetle ◽  
Dryocoetes Confusus

Response of Dryocoetes confusus and D. autographus (Coleoptera: Scolytidae) to enantiospecific pheromone baits

2004 ◽  
Vol 136 (3) ◽  
pp. 419-425 ◽  
Author(s):  
N.L. Jeans Williams ◽  
J.H. Borden
Keyword(s):  
Bark Beetle ◽  
Aggregation Pheromone ◽  
Bark Beetles ◽  
Field Studies ◽  
Pheromone Component ◽  
Male And Female ◽  
Dryocoetes Confusus

AbstractIn past field studies, the greatest response of western balsam bark beetles, Dryocoetes confusus Swaine, to traps was obtained with blends of (+)-exo-brevicomin and (+)- or (±)-endo-brevicomin, which imitate the natural male-produced aggregation pheromone. We conducted a trapping experiment comparing low-release enanti ospecific blends (9:1 (+)-exo-brevicomin:(+)-endo-brevicomin or 9:2 (+)-exo-brevicomin:(±)-endo-brevicomin released at 0.3, 0.1, or 0.03 mg per day) with the standard commercial (±)-exo-brevicomin bait released at 1.2 mg per day. Multiple-funnel traps baited with the experimental blends caught more D. confusus than the unbaited traps, but only traps with the 9:2 (+):(±) blend released at 0.3 and 0.03 mg per day caught significantly more male and female beetles than those baited with the standard bait. Thus, trap sensitivity can be improved with the addition of (±)-endo-brevicomin. The sympatric bark beetle D. autographus Ratzeburg was captured in significant numbers in traps baited with (±)-exo-brevicomin. A subsequent trapping experiment showed that D. autographus responded to (+)- or (±)-exo-brevicomin, but not to (−)-exo-brevicomin, suggesting that (+)-exo-brevicomin is the principal aggregation pheromone component in this species.

Assessment of Bentazon Tolerance in Pepper (Capsicumsp.)

1989 ◽  
Vol 3 (2) ◽  
pp. 307-312 ◽  
Author(s):  
Howard F. Harrison ◽  
Richard L. Fery
Keyword(s):  
Plant Breeding ◽  
Field Experiments ◽  
Sweet Pepper ◽  
Hot Pepper ◽  
Preliminary Evaluation ◽  
Susceptible Cultivar ◽  
High Degree ◽  
Breeding Techniques ◽  
Better Than

Preliminary evaluation of 11 pepper genotypes indicated a high degree of variability in bentazon tolerance. ‘Bohemian Chile’ and ‘Santanka’ hot pepper tolerated bentazon similarly in subsequent greenhouse and field experiments. Yields or shoot fresh weights of these two cultivars were not reduced by up to 9.0 kg ai/ha bentazon in the field. ‘Keystone Resistant Giant’ sweet pepper was more susceptible to bentazon compared to the tolerant cultivars, but it was more tolerant than the highly susceptible cultivar, ‘Sweet Banana’. An F1hybrid of Keystone Resistant Giant and Santanka tolerated bentazon better than Keystone Resistant Giant but slightly less than Santanka. Thus, bentazon tolerance in this genotype is genetically transferrable, and increasing bentazon tolerance through conventional plant breeding techniques may be possible.

Factors Affecting the Toxicity of Glyphosate Applied in the Recirculating Sprayer to Johnsongrass (Sorghum halepense)and Soybeans (Glycine max)

Weed Science ◽  
1980 ◽  
Vol 28 (1) ◽  
pp. 59-63 ◽  
Author(s):  
C. G. McWhorter ◽  
J. R. Williford
Keyword(s):  
Glycine Max ◽  
Field Experiments ◽  
Sorghum Halepense ◽  
Soybean Yield ◽  
Factors Affecting ◽  
Over The Top ◽  
Uniform Droplet ◽  
Better Than

Field experiments were conducted to determine optimum nozzle settings for applying glyphosate [N-(phosphonomethyl)glycine] in the recirculating sprayer for postemergence control of johnsongrass [Sorghum halepense(L.) Pers.] in soybeans [Glycine max(L.) Merr.]. Herbicide sprays were directed across the row to johnsongrass growing taller than soybeans in July and August. Herbicide not sprayed on johnsongrass was trapped and reused. Glyphosate at 0.56, 1.12, and 2.24 kg/ha applied with commercially available 25° spray nozzles provided johnsongrass control and soybean yields equal to those following applications with specialized uniform droplet nozzles. Glyphosate at 1.7 kg/ha applied in the recirculating sprayer using only one nozzle per row provided control of johnsongrass equal to or better than that from applications made with two, three, or four nozzles per row. Soybean yield following application of glyphosate at 1.7 kg/ha with one nozzle per row was equal to yields obtained following its application with two, three, or four nozzles per row, with or without surfactant at 0.1% in spray solutions. Soybean yield was higher with four nozzles per row than with one nozzle per row when 0.5% surfactant was included in spray solutions. Soybean injury was lower and yield was higher when glyphosate was applied in the recirculating sprayer rather than over-the-top with a conventional sprayer. Glyphosate at 1.12 kg/ha applied in the recirculating sprayer caused more injury to ‘Hill’ and ‘Bragg’ than to ‘Forrest’ or ‘Tracy’ soybeans.

Effectiveness of Starch Xanthide Formulations of Chloramben for Weed Control in Pumpkin (Cucurbita moschata)

Weed Science ◽  
1982 ◽  
Vol 30 (2) ◽  
pp. 169-174 ◽  
Author(s):  
Victor Raboy ◽  
Herbert J. Hopen
Keyword(s):  
Weed Control ◽  
Sandy Soil ◽  
Growing Season ◽  
Silt Loam ◽  
Cucurbita Moschata ◽  
Release Rates ◽  
Emulsifiable Concentrate ◽  
Loam Soil ◽  
In Parenthesis ◽  
Better Than

The persistence and effectiveness in pumpkin [Cucurbita moschata(Puch.) Poir.] weed control of several starch xanthide (SX) and commercial formulations of the ammonium (NH3) salt and methyl (CH3) ester of chloramben (3-amino-2,5-dichlorobenzoic acid) were studied in the laboratory and field. The soluble concentrate (SC) of chloramben NH3salt and the emulsifiable concentrate (EC) of chloramben CH3ester controlled weeds throughout the growing season on a silt loam soil. SC chloramben NH3salt was not effective, and EC chloramben CH3ester was inconsistent in weed control on sandy soil. Manipulation of the SX formulation produced products with slow, uniform release rates. The release rates (crosslinking reagent in parenthesis) rank as follows, from fastest to slowest: SX(Ca2+) CH3ester = SX(H2O2) acid > SX(H2O2) CH3ester > SX(Fe3+) acid > SX(Fe3+) CH3ester. In trials on silt loam and sand, SX formulations did not control weeds better than EC chloramben CH3ester.

Synergism of Grass Weed Control with Postemergence Combinations of SAN 582 and Fluazifop-P, Imazethapyr, or Sethoxydim

1998 ◽  
Vol 12 (2) ◽  
pp. 268-274 ◽  
Author(s):  
Robert C. Scott ◽  
David R. Shaw ◽  
Randall L. Ratliff ◽  
Larry J. Newsom
Keyword(s):  
Weed Control ◽  
Field Experiments ◽  
Full Rate ◽  
Reduced Rate ◽  
Grass Weed ◽  
Better Than

Greenhouse and field experiments were conducted to evaluate early postemergence (POST) tank mixtures of SAN 582 with fluazifop-P, imazethapyr, or sethoxydim. In the greenhouse, SAN 582 synergistically improved barnyardgrass, broadleaf signalgrass, and johnsongrass control from imazethapyr and sethoxydim. Half-rates of imazethapyr and sethoxydim tank-mixed with SAN 582 controlled grass weeds as well as full rates of either herbicide applied alone. Grass weed control with imazethapyr increased up to 40% with the addition of SAN 582. In field experiments, SAN 582 increased grass control with imazethapyr to a lesser degree than observed in the greenhouse. In a multispecies study, grass weed control increased up to 15% when SAN 582 was tank-mixed with a reduced rate of imazethapyr, although the full rate of imazethapyr applied POST with or without SAN 582 controlled grass weeds 80% or less. The combination of SAN 582 with sethoxydim was synergistic for barnyardgrass and johnsongrass control in this experiment. When applied POST in soybean, SAN 582 plus fluazifop-P or sethoxydim controlled barnyardgrass throughout the season better than a single POST application of a graminicide.

Late Glacial and Holocene records of tree-killing conifer bark beetles in Europe and North America: Implications for forest disturbance dynamics

The Holocene ◽  
2020 ◽  
Vol 30 (6) ◽  
pp. 847-857 ◽  
Author(s):  
Nick Schafstall ◽  
Niina Kuosmanen ◽  
Christopher J Fettig ◽  
Miloš Knižek ◽  
Jennifer L Clear
Keyword(s):  
North America ◽  
Bark Beetle ◽  
Fossil Record ◽  
Bark Beetles ◽  
Late Glacial ◽  
Ips Paraconfusus ◽  
Distribution Data ◽  
Dryocoetes Confusus ◽  
Combining Data ◽  
Fossil Records

Outbreaks of conifer bark beetles in Europe and North America have increased in scale and severity in recent decades. In this study, we identify existing fossil records containing bark beetle remains from the end of the Last Glacial Maximum (~14,000 cal. yr BP) to present day using the online databases Neotoma and BugsCEP and literature searches, and compare these data with modern distribution data of selected tree-killing species. Modern-day observational data from the Global Biodiversity Information Facility (GBIF) database was used to map recorded distributions from AD 1750 to present day. A total of 53 fossil sites containing bark beetle remains, from both geological and archeological sites, were found during our searches. Fossil sites were fewer in Europe ( n = 21) than North America ( n = 32). In Europe, 29% of the samples in which remains were found were younger than 1000 cal. yr BP, while in North America, remains were mainly identified from late Glacial (~14,000–11,500 cal. yr BP) sites. In total, the fossil records contained only 8 of 20 species we consider important tree-killing bark beetles in Europe and North America based on their impacts during the last 100 years. In Europe, Ips sexdentatus was absent from the fossil record. In North America, Dendroctonus adjunctus, Dendroctonus frontalis, Dendroctonus jeffreyi, Dendroctonus pseudotsugae, Dryocoetes confusus, Ips calligraphus, Ips confusus, Ips grandicollis, Ips lecontei, Ips paraconfusus, and Scolytus ventralis were absent. Overall, preserved remains of tree-killing bark beetles are rare in the fossil record. However, by retrieving bulk material from new and existing sites and combining data from identified bark beetle remains with pollen, charcoal, tree rings, and geochemistry, the occurrence and dominance of bark beetles, their outbreaks, and other disturbance events can be reconstructed.

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