Download or read book The Description and Biology of Bracon Lissogaster a New Parasite of the Wheat Steam Sawfly written by Kenneth Bradshaw Maughan and published by . This book was released on 1951 with total page 74 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bracon Lissogaster Mues written by Harry W. Somsen and published by . This book was released on 1956 with total page 10 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Bracon Lissogaster Mues written by H. W. Somsen and published by . This book was released on 1956 with total page 7 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Behavioral and Sensory Responses of Endemic Braconid Parasitoids to Changes in Volatile Emissions Induced by Wheat Stem Sawfly Cephus Cinctus Herbivory written by Oscar Gerardo Pérez and published by . This book was released on 2009 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: Bracon cephi (Gahan) and Bracon lissogaster Muesebeck are considered the most effective biological control agents of the wheat stem sawfly, Cephus cinctus Norton, probably the most serious wheat insect pest in the northern Great Plains of North America. The great difficulty in controlling this pest suggests an urgent need to improve our understanding of the chemical ecology of these parasitoids to enhance effective control of this pest. Chemical ecology has been demonstrated to be an effective tool in the control of important pests. Plants produce volatile compounds as defenses against herbivory. These compounds play an important role in host selection by herbivores and their natural enemies. Studies revealed that wheat plants infested by C. cinctus produce different amounts of specific compounds compared to uninfested plants. Synthetic compounds matching those produced by sawfly infested wheat plants were tested in three different concentrations against males and females B. cephi and B. lissogaster parasitoids using an electroantennogram system. Six compounds generated positive electrophysiological responses from the parasitoid antennae. Behavioral bioassays using the previous responsive compounds determined that three compounds were attractive to parasitoids of both sexes. To better understand parasitoid host seeking, it was important to quantify and determine the spatial distribution of these behaviorally active compounds as they were emitted from wheat plants. Volatile compounds were collected from infested and uninfested wheat plants at three different heights and two distances in the greenhouse. Greater amounts were collected from the infested plants immediately adjacent to the base of the plants. Field studies were performed to compare concentrations of volatile compounds between areas of heavy and light sawfly infestation. Greater amounts of behaviorally active volatile compounds were collected from areas of heavier sawfly infestation. In conclusion, results show that chemical ecology is a valuable tool in better understanding host seeking in this tritrophic system. This new information on volatile production and dispersal by sawfly infested plants and host seeking behavior of these parasitoids establishes the basis for future exploration of optimal blends of behaviorally active compounds used by parasitoids in host seeking, which may allow for more effective control of the wheat stem sawfly.
Download or read book The Biology of Microbracon Cephi Gahan an Important Native Parasite of the Wheat Stem Sawfly Cephus Cinctus Nort written by William Arnold Nelson and published by . This book was released on 1948 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: "During the past twenty-five years the wheat stem sawfly, Cephus cinctus Nort., has become one of the worst pests of wheat in the prairie provinces. Annual losses in the wheat-growing area of Saskatchewan have been estimated at up to seventeen million busheis (Farstad, 1945). This would seem to indicate inadequate natural control. There are, however, several native parasites of this pest, and of these Microbracon cephi Gahan is the most important. In some areas this parasite has been very effective in reducing severe sawfly infestations.[...]" --
Download or read book Mechanisms for Reproductive Isolation in Two Congeneric Parasitoids of the Wheat Stem Sawfly written by Rex Addison Davis and published by . This book was released on 2013 with total page 166 pages. Available in PDF, EPUB and Kindle. Book excerpt: Cephus cinctus Norton, the wheat stem sawfly, is Montana's most damaging wheat pest. The species is responsible for large yield reductions across the northern Great Plains, costing hundreds of millions of dollars every year. Two congeneric braconid parasitoid species, Bracon cephi Gahan and Bracon lissogaster Muesebeck (Hymenoptera: Braconidae), are found simultaneously in Montana wheat fields, are active at the same time of year and both use C. cinctusas a host. Their role as biological control agents of C. cinctusis currently being explored. It is unknown how these morphologically similar parasitoid species maintain reproductive isolation. This study explored several mechanisms allowing B. cephiand B. lissogaster to remain reproductively isolated and exposed new areas of study and questions of interest regarding the reproductive isolation of these species. No differences in reproductive timing were observed using field-based population abundance surveys, suggesting that alternative isolation mechanisms are being used. A group of candidate sex pheromones analyzed for presence, absence, and relative concentration in each of the parasitoid species' Dufour's glands indicated substantial differences between the two species. These differences suggest a possible role for the Dufour's gland in maintaining reproductive isolation. However, these candidate sex pheromones did not produce significantly different electrophysiological responses in B. cephiand B. lissogaster. Although this suggests that these candidate sex pheromones may not play a role, mating trials and behavioral assays conducted to assess the interactions between sex and species indicated that the species maintain reproductive isolation in laboratory settings.
Download or read book Mass Rearing of Bracon Cephi Gahan and B Lissogaster Muesebeck Parasitoids of Wheat Stem Sawfly Cephus Cinctus Norton and Temperature induced Mortality in Host Immatures written by Godshen Robert Pallipparambil Robert and published by . This book was released on 2006 with total page 224 pages. Available in PDF, EPUB and Kindle. Book excerpt: However, the sex ratio of the mass reared parasitoids was male biased indicating the absence of pre-mated females in the cages. The low number of male parasitoids in the rearing cages probably influenced this outcome. Experiments were conducted to assess possible temperature-induced mortality of sawfly immatures. Lethal temperatures and times for predicting mortality were calculated for the overwintering larval and pupal stages at 2 to 5 hr time intervals using probit analysis. The result shows that for both stages, mortality increased with increasing temperatures, and for a fixed temperature, the LT50 was lower for longer time intervals. The temperature-induced mortality experiments in the laboratory helped us to assess the lethal temperatures that should be avoided inside the rearing cages to enhance survival of the parasitoids. The temperatures inside the cages were significantly lower than those occurring in the field. These results provide the basis for wheat stem sawfly parasitoid mass rearing in walk-in cages.
Download or read book Monthly Catalog of United States Government Publications written by and published by . This book was released on 1957 with total page 1120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
