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Full-Text Articles in Life Sciences
Mechanisms Of Hybrid Sunflower Resistance To The Sunflower Midge (Diptera: Cecidomyiidae), Marc D. Anderson, Gary J. Brewer
Mechanisms Of Hybrid Sunflower Resistance To The Sunflower Midge (Diptera: Cecidomyiidae), Marc D. Anderson, Gary J. Brewer
Gary J. Brewer
A study was conducted to identify mechanisms of resistance in sunflower to the sunflower midge, Contarinia schulzi Gagné. Infestation ratings, larval counts, and damage ratings were used to quantify midge resistance in seven sunflower hybrids grown at three locations. Six of the seven hybrids possessed midge resistance. Each hybrid was further categorized with respect to infestation resistance, antibiosis, and tolerance. Two bud characteristics, percent open and size, were examined for their contribution to infestation resistance. The percentage of time that buds of each hybrid were open was negatively correlated with infestation (indicating a preference for the open characteristic). Infestations were …
Modification Of The Effect Of Bacillus Thuringiensis On Sunflower Moth (Lepidoptera: Pyralidae) By Dietary Phenols, Gary J. Brewer, Marc D. Anderson
Modification Of The Effect Of Bacillus Thuringiensis On Sunflower Moth (Lepidoptera: Pyralidae) By Dietary Phenols, Gary J. Brewer, Marc D. Anderson
Gary J. Brewer
The sunflower moth, Homoeosoma electellum (Hulst), a major pest of sunflower (Helianthus annuus L.), is susceptible to Bacillus thuringiensis Berliner, but field control has been inconsistent. Our study was done to determine whether phenolics in damaged sunflower tissue are in a conjugated or free form and whether they influence the toxicity of B. thuringiensis to the sunflower moth. Larvae fed diets containing B. thuringiensis had reduced survival and growth. The LD50 of B. thuringiensis was 52 international units of potency per gram of diet. Phenolic acids are general biocides. They were found in sunflower hybrids largely in the free (nonconjugated) …
Oviposition And Larval Bionomics Of Two Weevils (Coleoptera: Curculionidae) On Sunflower, Gary J. Brewer
Oviposition And Larval Bionomics Of Two Weevils (Coleoptera: Curculionidae) On Sunflower, Gary J. Brewer
Gary J. Brewer
Use of cultivated sunflower (Helianthus annum L.) as a host by two species of seed weevils, Smicronyx fulvus LeConte, the red sunflower seed weevil, and S. sordidus LeConte, the gray sunflower seed weevil, was compared using dissection of achenes from naturally and artificially infested plants. The gray seed weevil oviposits on the tips of unopened sunflower florets before anthesis. Larvae migrate through the corolla tube, penetrate the developing achene, and begin extensive feeding at the achene base. Achenes infested by the gray sunflower seed weevil are enlarged, lack an embryo, and appear to be a type of gall. The red …
Sensitivity To 2,4-D In Sunflower As An Indicator Of Tolerance To The Sunflower Midge (Diptera: Cecidomyiidae), Marc D. Anderson, Gary J. Brewer
Sensitivity To 2,4-D In Sunflower As An Indicator Of Tolerance To The Sunflower Midge (Diptera: Cecidomyiidae), Marc D. Anderson, Gary J. Brewer
Gary J. Brewer
Nine sunflower hybrids were evaluated for their sensitivity to 2,4-dichlorophenoxyacetic acid (2,4-D) as measured by the production of ethylene. Sensitivity to 2,4-D was then compared with the degree of field tolerance to the sunflower midge, Contarinia schulzi Gagné, exhibited by each hybrid. For the hybrids evaluated, ethylene production increased with 2,4-D concentration and sensitivity to 2,4-D was inversely proportional to midge tolerance. The procedure may be useful in identifying midge tolerant germplasm.
A Biotic Survey And Inventory Of The Dynastine Scarab Beetles Of Mesoamerica, North America, And The West Indies: Review Of A Long-Term, Multicountry Project, Brett C. Ratcliffe, Ronald D. Cave
A Biotic Survey And Inventory Of The Dynastine Scarab Beetles Of Mesoamerica, North America, And The West Indies: Review Of A Long-Term, Multicountry Project, Brett C. Ratcliffe, Ronald D. Cave
Brett C. Ratcliffe
This biotic inventory will document the species-level diversity of dynastine scarabs, their spatial and temporal distributions, ecological preferences, and biology. The long term, multi-country research project explores a biotically megadiverse region that is seriously at risk from deforestation, environmental homogenization, invasive species, and urban sprawl. Objectives of this survey are: 1) to understand the biodiversity of dynastine scarab beetles in Mesoamerica; 2) disseminate this information in print and electronic forms; 3) train students, parataxonomists, and collection managers in the study area about dynastine taxonomy and identification, care of collections, dissemination of information, and conservation; and 4) assemble authoritatively identified voucher …
Comparison Of Two Gelling Agents For Screwworm (Diptera: Calliphoridae) Larval Diets, David B. Taylor
Comparison Of Two Gelling Agents For Screwworm (Diptera: Calliphoridae) Larval Diets, David B. Taylor
David B. Taylor
A sodium polyacrylamide polyacrylate gelling agent, Water-Lock G-400, and a galactan polysaccharide agent, carrageenan, were compared for solidifying larval diets of the screwworm, Cochliomyia hominivorax (Coquerel). Water-Lock diet produced larger pupae with less larval mortality than did carrageenan diet. Pupae from larvae reared on the Water-Lock diet exhibited higher emergence and produced adults with higher fecundity. Water-Lock diet also produced larger larvae at 56 h after oviposition. Densities in excess of 300 mg of eggs (16,200 eggs) per liter of Water-Lock gelled diet did not increase larval yield but did reduce larval weight and survival.
Gelled Diet For Screwworm (Diptera: Calliphoridae) Mass Production, David B. Taylor, Jimmy C. Bruce, Rene Garcia
Gelled Diet For Screwworm (Diptera: Calliphoridae) Mass Production, David B. Taylor, Jimmy C. Bruce, Rene Garcia
David B. Taylor
A rearing system based on a diet gelled with Water-Lock G400, a synthetic superabsorbent (poly(2-propenamide-co-2-propenoic acid, sodium salt))( WL), was compared with the standard rearing system (liquid diet suspended in acetate fibers) for the mass production of screwworms, Cochlomyia hominivorax (Coquerel). The WL rearing system yielded 2% heavier pupae, 32% higher egg to pupa survival, and required 54% less diet and 88% less labor than the standard rearing system. Other advantages of the WL system include reduced susceptibility to suboptimal environmental conditions and labor practices, and characteristics conducive to centralization and mechanization of rearing procedures.
Response Of Screwworms (Diptera: Calliphoridae) To Changes In The Concentration Of Blood, Egg, And Milk In The Larval Diet, David B. Taylor
Response Of Screwworms (Diptera: Calliphoridae) To Changes In The Concentration Of Blood, Egg, And Milk In The Larval Diet, David B. Taylor
David B. Taylor
Larvae of screwworm, Cochliomyia hominivorax (Coquerel), were reared on diets with varying concentrations of whole dried bovine blood, whole dried egg, and nonfat dried milk. Pupal weight, egg to pupal survival, adult emergence, sex ratio, fecundity, and fertility were significantly affected by one or more of the dietary components. Curvilinear models for the effect of dietary component concentration on life history parameters were derived by multiple regression. Most models resulted in bell-shaped curves that were used to calculate optimal diet component concentrations. Biomass, survival, emergence, and fecundity were maximized at 6% blood, 5% egg, and 1.3% milk.
Life History Of A Ponderosa Pine Coneworm, Dioryctria Auranticella (Lepidoptera: Pyralidae), Judith E. Pasek, Mary Ellen Dix
Life History Of A Ponderosa Pine Coneworm, Dioryctria Auranticella (Lepidoptera: Pyralidae), Judith E. Pasek, Mary Ellen Dix
Judith E Pasek
Dioryctria auranticella (Grote), a coneworm that infests ponderosa pine, Pinus ponderosa Douglas ex. P. Lawson and Lawson, and Austrian pine, P. nigra Arnold, in southeastern Nebraska is univoltine. Head capsule measurements indicate five instars. First instars apparently overwinter in hibernaculae. Second and third instars feed in male and female pine flowers during early May. Fourth and fifth instars tunnel in second-year cones for about 2-3 wk between mid-May and mid-June and often require two cones to complete development. Larvae pupate within cones during June, and adults are active from mid-June to late July. at 26C, eggs hatch in 6-9 d. …
Insect Damage To Conelets, Second-Year Cones, And Seeds Of Ponderosa Pine In Southeastern Nebraska, Judith Pasek, Mary Dix
Insect Damage To Conelets, Second-Year Cones, And Seeds Of Ponderosa Pine In Southeastern Nebraska, Judith Pasek, Mary Dix
Judith E Pasek
Rhyacionia spp. and Retinia metallica (Busck) annually caused conelet losses of 8.2% and 5.4%, respectively. Abortion and disappearance of conelets caused by Leptoglossus occidentalis Heidemann or physiological dysfunction averaged 65.7% and were reduced by 13% when conelets were protected with screen cages. Survival of conelets averaged 19.5%. Of those remaining, 76.8% appeared healthy after the second growing season. Dioryctria spp. annually damaged an average of 14.2% of the second-year cones. Mean annual seed potentials ranged from 77.4 to 127.1 seeds per cone, but mean annual seed yields ranged from only 0.4 to 8.1 filled seeds per cone. Caging cones to …