Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 20 of 20

Full-Text Articles in Life Sciences

Mechanisms Of Hybrid Sunflower Resistance To The Sunflower Midge (Diptera: Cecidomyiidae), Marc D. Anderson, Gary J. Brewer Jul 2013

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 Jul 2013

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) …


Development Of Banded Sunflower Moth (Lepidoptera: Cochylidae) And Sunflower Moth (Lepidoptera: Pyralidae) On Three Diets, Jawahar Jyoti, Gary Brewer Jul 2013

Development Of Banded Sunflower Moth (Lepidoptera: Cochylidae) And Sunflower Moth (Lepidoptera: Pyralidae) On Three Diets, Jawahar Jyoti, Gary Brewer

Gary J. Brewer

A comparative study of the effects of sunflower moth diet, banded sunflower moth diet, and a modified sunflower moth diet was conducted on banded sunflower moth, Cochylis hospes Walsingham, and sunflower moth, Homoeosoma electellum (Hulst). Developmental times and survival to the pupal and adult stages were measured for each diet and pest species. Modified sunflower moth diet with incorporated sunflower leaf tissue gave faster developmental times and a higher percent pupation and adult eclosion for both sunflower moth species than either sunflower moth diet or banded sunflower moth diet. The modified sunflower moth diet that incorporates sunflower leaf tissue provides …


Using Banded Sunflower Moth (Lepidoptera: Tortricidae) Egg Density To Estimate Damage And Economic Distance In Oilseed Sunflower, Kirk D. Mundal, Gary J. Brewer Jul 2013

Using Banded Sunflower Moth (Lepidoptera: Tortricidae) Egg Density To Estimate Damage And Economic Distance In Oilseed Sunflower, Kirk D. Mundal, Gary J. Brewer

Gary J. Brewer

The banded sunflower moth, Cochylis hospes Walsingham (Lepidoptera: Tortricidae), is an important economic pest of sunflower in the Upper Great Plains of North America. Economic losses due to reductions in seed number, weight, and quality can be significant. Previously, the potential for economic losses were estimated by sampling for adult moths. However, sampling for moths can be difficult and inaccurate. An alternative is to sample for banded sunflower moth eggs, which can be accurately counted in the field by using a binocular 3.5 headband magnifier. The egg counts are used to calculate the economic injury level (EIL): EIL …


Oviposition And Larval Bionomics Of Two Weevils (Coleoptera: Curculionidae) On Sunflower, Gary J. Brewer Jul 2013

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 …


Review Of Integrated Pest Management In The Global Arena, By K. M. Maredia, D. Dakouo, And D. Mota-Sanchez, Gary J. Brewer Jul 2013

Review Of Integrated Pest Management In The Global Arena, By K. M. Maredia, D. Dakouo, And D. Mota-Sanchez, Gary J. Brewer

Gary J. Brewer

Integrated Pest Management in the Global Arena is a large book with 39 chapters and >500 pages of text. Despite the wide range of topics and numerous contributing authors, the book is consistently well written and worth reading in its entirety or by selectively choosing particular topics. The book should be a welcome reference for researchers and extension personnel across disciplines as well as for policy makers in government agencies and nongovernmental organizations working to promote integrated pest management (IPM) and sustainable agriculture. The reader can select any chapter and find a relevant discussion of IPM. As someone who teaches …


Characterization Of Olfactory Sensilla Of Stomoxys Calcitrans And Electrophysiological Responses To Odorant Compounds Associated With Hosts And Oviposition Media, K. Tangtrakulwanich, Han Chen, Frederick P. Baxendale, Gary J. Brewer, J. J. Zhu Jul 2013

Characterization Of Olfactory Sensilla Of Stomoxys Calcitrans And Electrophysiological Responses To Odorant Compounds Associated With Hosts And Oviposition Media, K. Tangtrakulwanich, Han Chen, Frederick P. Baxendale, Gary J. Brewer, J. J. Zhu

Gary J. Brewer

Stable flies, Stomoxys calcitrans L. (Diptera: Muscidae), are economically important biting flies that have caused billions of dollars in losses in the livestock industry. Field monitoring studies have indicated that olfaction plays an important role in host location. To further our understanding of stable fly olfaction, we examined the antennal morphology of adults using scanning electron microscopy techniques. Four major types of sensillum were found and classified as: (a) basiconic sensilla; (b) trichoid sensilla with three subtypes; (c) clavate sensilla, and (d) coeloconic sensilla. No significant differences between male and female flies in abundances (total numbers) of these sensillum types …


Sunflower Beetle (Coleoptera: Chrysomelidae): Pattern Of Larval Distribution And Parasitism In Cultivated Sunflower Fields, Gary J. Brewer, Laurence D. Charlet Jul 2013

Sunflower Beetle (Coleoptera: Chrysomelidae): Pattern Of Larval Distribution And Parasitism In Cultivated Sunflower Fields, Gary J. Brewer, Laurence D. Charlet

Gary J. Brewer

The sunflower beetle, Zygogramma exclamationis (Fabricius), is a major pest of commercial sunflower, Helianthus annuus L. (Asteraceae), in the Plains area of central North America. Although an economic injury level for the sunflower beetle has been determined, in-field distributions of the larvae and their natural enemies have not been described. Over a three year period, fields were sampled for sunflower beetle larvae and for larvae of the endoparasitoid, Myiopharus macellus (Reinhard). Sunflower beetle larvae were generally found to have aggregated distributions. Knowledge of the distribution pattern will allow the development of more efficient sunflower beetle sampling protocols. Parasitism rates of …


Nepetalactones From Essential Oil Of Nepeta Cataria Represent A Stable Fly Feeding And Oviposition Repellent, J. J. Zhu, Dennis R. Berkebile, C. E. Dunlap, A. Zhang, D. Boxler, K. Tangtrakulwanich, R. Behle, Frederick P. Baxendale, Gary J. Brewer Jul 2013

Nepetalactones From Essential Oil Of Nepeta Cataria Represent A Stable Fly Feeding And Oviposition Repellent, J. J. Zhu, Dennis R. Berkebile, C. E. Dunlap, A. Zhang, D. Boxler, K. Tangtrakulwanich, R. Behle, Frederick P. Baxendale, Gary J. Brewer

Gary J. Brewer

The stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), is one of the most serious pests to livestock. It feeds mainly on cattle and causes significant economic losses in the cattle industry. Standard stable fly control involving insecticides and sanitation is usually costly and often has limited effectiveness. As we continue to evaluate and develop safer fly control strategies, the present study reports on the effectiveness of catnip (Nepeta cataria L.) oil and its constituent compounds, nepetalactones, as stable fly repellents. The essential oil of catnip reduced the feeding of stable flies by >96% in an in vitro bioassay system, compared …


Contact And Fumigant Toxicity Of A Botanical-Based Feeding Deterrent Of The Stable Fly, Stomoxys Calcitrans (Diptera: Muscidae), Junwei Zhu, Andrew Li, Sara Pritchard, Khanobporn Tangtrakulwanich, Frederick Baxendale, Gary Brewer Jul 2013

Contact And Fumigant Toxicity Of A Botanical-Based Feeding Deterrent Of The Stable Fly, Stomoxys Calcitrans (Diptera: Muscidae), Junwei Zhu, Andrew Li, Sara Pritchard, Khanobporn Tangtrakulwanich, Frederick Baxendale, Gary Brewer

Gary J. Brewer

The stable fly, Stomoxys calcitrans (L.), has been considered one of the most serious biting flies of confined and pastured livestock. The economic losses caused by the stable fly to the cattle industry in the United States exceed $2 billion annually. Current practices for managing stable flies using insecticides provide only marginal control. Insecticide resistance has also been recently reported in stable flies. The present study reports the use of plant-based insecticides, for example, essential oils, as alternatives for managing this fly pest. The toxicity of several plant essential oils and selected ingredient compounds was evaluated by contact and fumigant …


Screening Sunflower For Tolerance To Sunflower Midge Using The Synthetic Auxin 2,4-Dichlorophenoxyacetic Acid, Gary J. Brewer, Marc D. Anderson, N. V. Rama Raje Urs Jul 2013

Screening Sunflower For Tolerance To Sunflower Midge Using The Synthetic Auxin 2,4-Dichlorophenoxyacetic Acid, Gary J. Brewer, Marc D. Anderson, N. V. Rama Raje Urs

Gary J. Brewer

The sunflower midge, Contarinia schulzi Gagné, causes economic damage by inducing abnormal growth in infested heads (capitula) of sunflower, Helianthus annuus L. The primary objective of this study was to determine whether sunflower midge damage could be simulated and whether that simulated damage could be used to select midge-tolerant sunflower germplasm. An additional objective was to develop a quantitative alternative to the scoring systems used to visually estimate damage. Sunflower plants were treated by injecting buds with the synthetic auxin 2,4-dichlorophenoxyacetic acid (2,4-D), which resulted in a distortion of the head morphology that was similar in appearance to the damage …


Resistance In Sunflower And Interaction With Bacillus Thuringiensis For Control Of Banded Sunflower Moth (Lepidoptera: Tortricidae), Jawahar L. Jyoti, Gary J. Brewer Jul 2013

Resistance In Sunflower And Interaction With Bacillus Thuringiensis For Control Of Banded Sunflower Moth (Lepidoptera: Tortricidae), Jawahar L. Jyoti, Gary J. Brewer

Gary J. Brewer

Four sunflower accessions were compared with a susceptible check, hybrid ‘894’, in the greenhouse to determine their resistance to the banded sunflower moth, Cochylis hospes Walsingham, and their interaction with Bacillus thuringiensis Berliner variety kurstaki. Antibiosis, expressed as lower larval weights, was detected in all of the accessions. In addition to being antibiotic, sunflower accession Ames 3291 was antixenotic to banded sunflower moth oviposition and exhibited an additional impact on larval weight when B. thuringiensis was applied. By itself, B. thuringiensis provided better control of banded sunflower moth than the resistance tested. However, banded sunflower moth-resistant sunflower would be a …


Sunflower Resistance To The Red Sunflower Seed Weevil (Coleoptera: Curculionidae), Huihua Gao, Gary Brewer Jul 2013

Sunflower Resistance To The Red Sunflower Seed Weevil (Coleoptera: Curculionidae), Huihua Gao, Gary Brewer

Gary J. Brewer

The red sunflowerseed weevil, Smicronyx fulvus LeConte (Coleoptera: Curculionidae), is a major insect pest of sunflower in North Dakota, South Dakota, and Minnesota. Economic damage is caused by the larvae which are internal seed feeders. During the 1992-1995 growing seasons, sunflower accessions were artificially infested and evaluated for resistance to the red sunflower seed weevil. Accessions 170411, 253417, and 170424 were resistant to the red sunflower seed weevil. Morphological types within accessions170411 and 170424 varied for seed and pollen color and resistance to the red sunflower seed weevil. The resistant variant of accession170424 had 45% of the seed damage of …


Within-Field Distribution Of The Sunflower Midge (Diptera: Cecidomyiidae), E. W. Hodgson, I. V. Macrae, Gary J. Brewer Jul 2013

Within-Field Distribution Of The Sunflower Midge (Diptera: Cecidomyiidae), E. W. Hodgson, I. V. Macrae, Gary J. Brewer

Gary J. Brewer

The sunßower midge, Contarinia schulzi Gagne (Diptera: Cecidomyiidae), is a pest of cultivated sunflower (Helianthus annuus L.). Larval feeding can cause damage and yield loss to the sunflower head. Adult emergence is extended and larvae are well protected in the sunflower receptacle, making chemical control methods difficult and expensive. Sunflower midge enter sunflower fields at the edges but fieldwide distributions occur, although the dynamics are not fully understood. Two commercial fields in 1999 and one field in 2000 were systematically sampled by dividing each field into fixed sample points. Mean egg and larval densities from each sample point were used …


Sensitivity To 2,4-D In Sunflower As An Indicator Of Tolerance To The Sunflower Midge (Diptera: Cecidomyiidae), Marc D. Anderson, Gary J. Brewer Jul 2013

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.


Description Of Achene Damage By The Red Sunflower Seed Weevil, The Banded Sunflower Moth, And The Sunflower Moth, Chengwang Peng, Gary J. Brewer Jul 2013

Description Of Achene Damage By The Red Sunflower Seed Weevil, The Banded Sunflower Moth, And The Sunflower Moth, Chengwang Peng, Gary J. Brewer

Gary J. Brewer

There are four major insect pests attacking achenes of sunflower in the Great Plains of North America (Charlet et al., 1987); the red sunflower seed weevil, Smicronyx fulvus LeConte (Coleoptera: Curculionidae), the gray sunflower seed weevil, S. sordidus LeConte (Coleoptera: Curculionidae), the banded sunflower moth, Cochylis hospes (Walsingham) (Lepidoptera: Cochylidae), and the sunflower moth, Homoeosoma electellum (Hulst) (Lepidoptera: Pyralidae). Identification of achenes damaged by larvae of these species is important for assessment of yield loss caused by each species (Peng and Brewer, 1995). Achenes infested by the gray sunflower seed weevil are easily identified because they are enlarged and protrude …


Honey Bees (Hymenoptera: Apidae) As Vectors Of Bacillus Thuringiensis For Control Of Banded Sunflower Moth (Lepidoptera: Tortricidae), Jawahar L. Jyoti, Gary J. Brewer Jul 2013

Honey Bees (Hymenoptera: Apidae) As Vectors Of Bacillus Thuringiensis For Control Of Banded Sunflower Moth (Lepidoptera: Tortricidae), Jawahar L. Jyoti, Gary J. Brewer

Gary J. Brewer

A study was conducted in 1996 and 1997 to determine if honey bees, Apis mellifera L., could vector Bacillus thuringiensis Berliner variety kurstaki from hives equipped with a pathogen applicator to sunflower capitula and if the amount of B. thuringiensis deposited on the capitula would be sufficient to control the banded sunflower moth, Cochylis hospes Walsingham. The study demonstrated that honey bees became contaminated with B. thuringiensis as they exited hives equipped with filled pathogen applicators and deposited enough B. thuringiensis on the capitula to cause banded sunflower moth larval mortality. When 2 methods of applying B. thuringiensis were compared, …


Median Lethal Concentration And Efficacy Of Bacillus Thuringiensis Against Banded Sunflower Moth (Lepidoptera: Tortricidae), Jawahar L. Jyoti, Gary J. Brewer Jul 2013

Median Lethal Concentration And Efficacy Of Bacillus Thuringiensis Against Banded Sunflower Moth (Lepidoptera: Tortricidae), Jawahar L. Jyoti, Gary J. Brewer

Gary J. Brewer

This study was conducted to determine dose-mortality response of the banded sunflower moth, Cochylis hospes Walsingham, to Bacillus thuringiensis Berliner and its effect on sunflower seed damage and yield. Of B. thuringiensis products tested, Cutlass AF and Javelin WG had the lowest LC50 values and highest slopes and relative potencies for C. hospes. Javelin WG was superior to the other B. thuringiensis materials tested and to Asana XL in preventing seed damage. Sunflower heads sprayed with Javelin WG had higher yields than sunflower heads sprayed with Asana XL or the other B. thuringiensis products tested. Asana XL is a standard …


Sequential Sampling Plans For The Red Sunflower Seed Weevil (Coleoptera: Curculionidae) In Oilseed Sunflower, Chengwang Peng, Gary J. Brewer Jul 2013

Sequential Sampling Plans For The Red Sunflower Seed Weevil (Coleoptera: Curculionidae) In Oilseed Sunflower, Chengwang Peng, Gary J. Brewer

Gary J. Brewer

Decision making on control of the red sunflower seed weevil, Smicronyx fulvus LeConte, requires a reliable and efficient method for classifying the pest population. The objective of this study was to develop sequential sampling plans for red sunflower seed weevil control in oilseed sunflower. Sequential classification sampling plans were developed from Wald's sequential probability ratio test (SPRT) by using a negative binomial distribution. Operating characteristic and average sample number functions were computed for a range of k values. Two sampling plans were developed for the economic thresholds of six and eight weevils per sunflower head, based on a k value …


Spatial Distribution And Sequential Sampling Plans For The Banded Sunflower Moth (Lepidoptera: Cochylidae) Eggs On Sunflower, C Peng, Gary Brewer Dec 1995

Spatial Distribution And Sequential Sampling Plans For The Banded Sunflower Moth (Lepidoptera: Cochylidae) Eggs On Sunflower, C Peng, Gary Brewer

Gary J. Brewer

No abstract provided.