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P. M. Buckley - One of the best experts on this subject based on the ideXlab platform.
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fall armyworm lepidoptera noctuidae and Southwestern Corn Borer lepidoptera crambidae leaf feeding damage and its effect on larval growth on diets prepared from lyophilized Corn leaves 1
Journal of Agricultural and Urban Entomology, 2008Co-Authors: Paul W Williams, P. M. BuckleyAbstract:Fall armyworm, Spodoptera frugiperda (J.E. Smith), and Southwestern Corn Borer, Diatraea grandiosella Dyar, are economically important pests of maize (Zea mays L.) in the southeastern United States. These insects attack plants in both the vegetative and reproductive stage so f growth. Plant resistance is widely considered a desirable means for reducing losses to both insects, and Corn germplasm lines with resistance to leaf feeding damage have been developed and released. Fall armyworm and Southwestern Corn Borer larvae feeding on resistant genotypes grow more slowly than those feeding on susceptible genotypes. The objectives of the investigation were to evaluate 20 single cross maize hybrids for leaf feeding damage by southwest- ern Corn Borer and fall armyworm, to compare larval growth on laboratory diets prepared from lyophilized leaf tissue of single cross hybrids with different levels of resistance to leaf feeding, and to determine whether larval growth differed between diets prepared from leaf tissue collected from plants previously infested with Southwestern Corn Borer or fall armyworm and non- infested plants. Both fall armyworm and Southwestern Corn Borer larvae weighed significantly less when fed on laboratory diets prepared from lyophilized leaf tissue of resistant single cross hybrids than susceptible hybrids. When tissue from either resistant or susceptible plants that had been infested with either insect in the field was used in bioassays, larval weights were further reduced. It appears that both constitutive and induced defensive mechanisms may be operating.
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genetic basis of resistance to fall armyworm lepidoptera noctuidae and Southwestern Corn Borer lepidoptera crambidae leaf feeding damage in maize
Journal of Economic Entomology, 2007Co-Authors: Thomas D Brooks, Paul W Williams, Shaun B Bushman, Micheal D Mcmullen, P. M. BuckleyAbstract:Leaf-feeding damage by first generation larvae of fall armyworm, Spodopter frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), and Southwestern Corn Borer, Diatraea grandiosella Dyar (Lepidoptera: Crambidae), cause major economic losses each year in maize, Zea mays L. A previous study identified quantitative trait loci (QTL) contributing to reduced leaf-feeding damage by these insects in the maize line Mp704. This study was initiated to identify QTL and their interactions associated with first generation leaf-feeding damage by fall armyworm and Southwestern Corn Borer. QTL associated with fall armyworm and Southwestern Corn Borer resistance in resistant line Mp708 were identified and compared with Mp704. Multiple trait analysis (MTA) of both data sets was then used to identify the most important genetic regions affecting resistance to fall armyworm and Southwestern Corn Borer leaf-feeding damage. Genetic models containing four and seven QTL explained Southwestern Corn Borer and fall armyworm resistance, respectively, in Mp708. Key genomic regions on chromosomes 1, 5, 7, and 9 were identified by MTA in Mp704 and Mp708 that confer resistance to both fall armyworm and Southwestern Corn Borer. QTL regions on chromosomes 1, 5, 7, and 9 contained resistance to both insects and were present in both resistant lines. These regions correspond with previously identified QTL related to resistance to other lepidopteran insects, suggesting that broad-spectrum resistance to leaf feeding is primarily controlled by only a few genetic regions in this germplasm.
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aflatoxin accumulation in Corn hybrids infested at different growth stages with Southwestern Corn Borer lepidoptera crambidae 1
2007Co-Authors: Paul W Williams, P. M. Buckley, Gary L Windham, Christopher A DavesAbstract:Aflatoxin is a potent toxin produced by the fungus Aspergillus flavus. Contamination of Corn, Zea mays L., with aflatoxin greatly reduces the value of Corn grain and is a major impediment to profitable Corn production in the South. Infestation of developing Corn ears with Southwestern Corn Borer, Diatraea grandiosella Dyar (Lepidopera: Crambidae), increases the likelihood of aflatoxin contamination. In this investigation, six Corn hybrids with differ- ent levels of resistance to Southwestern Corn Borer damage and aflatoxin con- tamination were evaluated for damage by Southwestern Corn Borer and afla- toxin contamination after infestation with Southwestern Corn Borer at 7-d intervals from 35-84 d after planting and inoculation with an A. flavus conidial suspension. Transgenic (Bt) hybrids exhibited excellent resistance to south- western Corn Borer and less aflatoxin contamination than conventional ver- sions of the same hybrids. A conventional hybrid with intermediate resistance to Southwestern Corn Borer also exhibited relatively low levels of aflatoxin contamination. A conventional hybrid selected for resistance to aflatoxin con- tamination was heavily damaged by Southwestern Corn Borer, but exhibited little aflatoxin contamination. Hybrids that have resistance to both southwest- ern Corn Borer and aflatoxin contamination appear to have the greatest poten- tial for effectively reducing losses to aflatoxin in the South. Damage by south- western Corn Borer to plants in both the vegetative and reproductive stage so f growth can increase aflatoxin contamination in susceptible Corn hybrids.
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Identifying Resistance in Corn to Southwestern Corn Borer (Lepidoptera: Crambidae), Fall Armyworm (Lepidoptera: Noctuidae), and Corn Earworm (Lepidoptera: Noctuidae) 1
2007Co-Authors: W P Williams, P. M. Buckley, Christopher A DavesAbstract:Southwestern Corn Borer, Diatraea grandiosella Dyar (Lepi- doptera: Crambidae); fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae); and Corn earworm, Helicoverpa zea Boddie (Lepi- doptera: Noctuidae), are major insect pests of Corn, Zea mays L., in the south- ern United States. Corn hybrids produced from resistant germplasm were evaluated together with Bt and nonBt commercial hybrids in field tests and laboratory bioassays for resistance to leaf and ear damage by Southwestern Corn Borer, fall armyworm, and Corn earworm. The Bt hybrids, Mp496 × Mp716 and Mp704 × Mp716, exhibited resistance to leaf feeding damage by south- western Corn Borer and fall armyworm. The Bt hybrids sustained significantly less Southwestern Corn Borer ear damage than their nonBt versions. Those genotypes expressing resistance to leaf feeding also showed resistance, as in- dicated by reduced larval growth or survival in laboratory bioassays base do n lyophilized leaf tissue, to Southwestern Corn Borer, fall armyworm, and Corn earworm. Only the Bt hybrids expressed resistance when larval growth was evaluated in bioassays based on lyophilized husk tissues. Using both field tests and laboratory bioassays to assess resistance to these insects will enhance efforts to identify useful germplasm and determine factors contributing to resistance.
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quantitative trait loci conferring resistance to fall armyworm and Southwestern Corn Borer leaf feeding damage
Crop Science, 2005Co-Authors: Thomas D Brooks, Paul W Williams, Martha C Willcox, P. M. BuckleyAbstract:Southwestern Corn Borer (Diatraea grandiosella Dyar) and fall armyworm [Spodoptera frugiperda (J.E. Smith)] damage ratings were measured on an F2-derived maize (Zea mays L.) population segregating for leaf feeding resistance following artificial infestation with neonates. Damage ratings for each insect were recorded in replicated trials at three locations and used in conjunction with a genetic linkage map to identify quantitative trait loci (QTL) associated with resistance. Significant QTL and their interactions were estimated by multiple interval mapping analysis. Resistance to Southwestern Corn Borer leaf feeding was fit to a model containing eight QTL and two interactions explaining 20% of the phenotypic variation. A model containing seven QTL and one interaction best fit resistance to fall armyworm leaf feeding damage, and it explained approximately 14% of the phenotypic variation. Three QTL located on chromosomes 6, 9, and 10 affect leaf feeding damage ratings of both insects with similar effects and gene action. Minor interaction effects were observed. The QTL on chromosomes 1, 5, and 9 correspond to previously identified regions affecting resistance to Southwestern Corn Borer. Insect resistance genes including the mir family of genes located on chromosome 6 and the glossylS locus on chromosome 9 fall within Chromosomal regions of QTL predicted in this study. This study confirms that resistance to fall armyworm and Southwestern Corn Borer involves many of the same QTL and candidate genes for insect resistance include the glossy 15 candidate locus on chromosome 9.
F M Davis - One of the best experts on this subject based on the ideXlab platform.
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Plant resistance and its effect on the peritrophic membrane of Southwestern Corn Borer (Lepidoptera: Crambidae) larvae.
Journal of economic entomology, 2007Co-Authors: Chris A. Daves, F M Davis, W P Williams, G. T. Baker, P. W. K., W. A. Monroe, S. MohanAbstract:The Southwestern Corn Borer, Diatraea grandiosella Dyar (Lepidoptera: Crambidae), is a serious pest of Corn, Zea mays L., in the southern United States. Corn germplasm lines with conventional genetic leaf-feeding resistance to this pest, the fall armyworm, Spodoptera frugiperda (J.E. Smith), and other lepidopterans have been released to the public by USDA-ARS scientists located in Mississippi. Recent studies suggest the insect resistant lines disrupt the integrity of the peritrophic membrane of the fall armyworm. The objectives of this study were to investigate any morphological differences in the structure of the peritrophic membrane of Southwestern Corn Borer larvae feeding on resistant and susceptible Corn hybrids and to quantify the damage. Larvae were reared under field and laboratory conditions on three Corn hybrids (two resistant and one susceptible). Scanning electron microscopy was used to examine the peritrophic membrane for abnormalities such as holes or tears and to count the holes or tears in the membrane. Differences in the degree of damage to peritrophic membrane of larvae fed on resistant and susceptible plants were not detected. Up to five distinct layers of the membrane were observed in each larva. Variation in the amounts of damage to the peritrophic membrane observed from larvae feeding on all plant material was high. Plant resistance adversely affects growth and development of Southwestern Corn Borer larvae, and further investigations are needed to explain the role of plant resistance and its relation to peritrophic membrane in Southwestern Corn Borer larvae.
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impact of plant resistance on Southwestern Corn Borer lepidoptera crambidae biology and plant damage
Journal of Economic Entomology, 2007Co-Authors: Chris A. Daves, W P Williams, F M DavisAbstract:Southwestern Corn Borer, Diatraea grandiosella Dyar (Lepidoptera: Crambidae), is a major insect pest of Corn, Zea mays L., in the southern United States. Germplasm lines with resistance to Southwestern Corn Borer have been developed and released by the USDA-ARS. Two single-cross hybrids produced by crossing germplasm lines with resistance to Southwestern Corn Borer and a susceptible single-cross hybrid were infested with Southwestern Corn Borer larvae in a 2-yr field test conducted in Mississippi. The susceptible hybrid sustained significantly more leaf damage and stalk tunneling than either resistant hybrid. The number of tunnels and the length of tunneling were significantly lower on the resistant hybrids. In 2003, up to 15 times more tunneling was observed on the susceptible hybrid. Larvae feeding on the resistant hybrids were delayed in their movement from the whorl to the stalk and larval survival was 50% lower on the resistant hybrids than on the susceptible hybrid. Larvae recovered from the susceptible hybrid 7-14 d after infestation weighed twice as much as those recovered from the resistant hybrids. Similar differences in larval weight were observed in the laboratory when larvae were reared on diets prepared from lyophilized tissue from the three hybrids. These results provide a foundation for other investigations designed to identify and determine the roles of specific genes and gene families associated with Southwestern Corn Borer resistance in Corn.
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impact of a novel species of nosema on the Southwestern Corn Borer lepidoptera crambidae
Journal of Economic Entomology, 2003Co-Authors: A M Lawrence, G D Inglis, F M DavisAbstract:A study was undertaken to elucidate the impact of an undescribed Nosema sp. on the Southwestern Corn Borer (SWCB; Diatraea grandiosella Dyar). The Nosema sp. (isolate 506) included in the study was isolated from an overwintering SWCB larva in Mississippi. It was highly infectious per os, with a median infective dose of 2.0 × 103 spores per larva. Even at the highest dosage tested (107 spores per larva), minimal mortality (≤3%) was observed in infected larvae, pupae, and adults reared in the laboratory on an artificial diet. However, infected pupae (0- and 7-d-old) were smaller, and the time to adult eclosion from pupation was slightly increased. Furthermore, the number of eggs produced by infected SWCB female moths substantially decreased (32%), and this effect was most pronounced on day 2, when the greatest number of eggs were oviposited by infected and noninfected moths. For eggs produced by infected females mated with infected males, hatch was slightly decreased by 16 and 15% for eggs laid on days 2 and 3, respectively. In addition, egg hatch was reduced in eggs oviposited by noninfected females mated with infected males on day 3. A low prevalence of infection (<6%) was observed in the F1 generation originating from infected females mating with noninfected males, from noninfected females mating with infected males, and from infected females mating with infected males. Nosema 506 spores were observed in the proximity of reproductive tissues of infected female and male moths. Spores also were detected on the chorion surface and within eggs laid by infected females. Furthermore, 1–11% of larvae hatching from surface-sterilized eggs were infected by Nosema 506 indicating a transovarial mechanism of transmission.
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conventional resistance of experimental maize lines to Corn earworm lepidoptera noctuidae fall armyworm lepidoptera noctuidae Southwestern Corn Borer lepidoptera crambidae and sugarcane Borer lepidoptera crambidae
Journal of Economic Entomology, 2000Co-Authors: Craig A Abel, Richard L Wilson, Billy R Wiseman, W H White, F M DavisAbstract:Plant resistance is a useful component of integrated pest management for several insects that are economically damaging to maize, Zea mays L. In this study, 15 experimental lines of maize derived from a backcross breeding program were evaluated for resistance to Corn earworm, Helicoverpa zea (Boddie); fall armyworm, Spodoptera frugiperda (J. E. Smith); Southwestern Corn Borer, Diatraea grandiosella Dyar; and sugarcane Borer, Diatraea saccharalis (F.). Experimental line 100-R-3 was resistant in the field to leaf feeding by fall armyworm and line 116-B-10 was resistant in the field to leaf feeding by fall armyworm and leaf and stalk feeding by Southwestern Corn Borer. When Corn earworm larvae were fed field harvested silks from experimental line 81-9-B in the laboratory, their pupal weights were significantly lower than the pupal weights of larvae that were fed silks from the resistant control, Zapalote Chico. Maysin levels lower than those commonly associated with Corn earworm resistance were present in the resistant experimental line, 107-8-7, indicating a new basis confers resistance to Corn earworm in this line. These resistant experimental lines will provide plant breeders with new sources of resistance to lepidopterous insects for the development of improved maize breeding populations.
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effects of the Southwestern Corn Borer on aspergillus flavus kernel infection and aflatoxin accumulation in maize hybrids
Plant Disease, 1999Co-Authors: Gary L Windham, W P Williams, F M DavisAbstract:ABSTRACT Field studies were conducted in 1995 to 1997 to determine the effect of the Southwestern Corn Borer (SWCB) on Aspergillus flavus kernel infection and aflatoxin accumulation in maize hybrids. In 1995, when A. flavus conidia were applied to silks in a spray and SWCB neonate larvae in maize cob grits were placed in the leaf axil at the top ear of commercial hybrids, aflatoxin contamination and A. flavus kernel infection were highest in plants treated with both the fungus and the insect. In 1996, using the same inoculation and infestation techniques, aflatoxin levels and kernel infection were much lower than in 1995 and SWCB had no effect on aflatoxin contamination or kernel infection. In another study in 1996, the effect of SWCB on aflatoxin contamination and A. flavus kernel infection in hybrids resistant and susceptible to A. flavus was determined. The inoculation-infestation technique involved applying maize cob grits containing A. flavus conidia and SWCB larvae to silks. When SWCB was combined w...
Paul W Williams - One of the best experts on this subject based on the ideXlab platform.
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fall armyworm lepidoptera noctuidae and Southwestern Corn Borer lepidoptera crambidae leaf feeding damage and its effect on larval growth on diets prepared from lyophilized Corn leaves 1
Journal of Agricultural and Urban Entomology, 2008Co-Authors: Paul W Williams, P. M. BuckleyAbstract:Fall armyworm, Spodoptera frugiperda (J.E. Smith), and Southwestern Corn Borer, Diatraea grandiosella Dyar, are economically important pests of maize (Zea mays L.) in the southeastern United States. These insects attack plants in both the vegetative and reproductive stage so f growth. Plant resistance is widely considered a desirable means for reducing losses to both insects, and Corn germplasm lines with resistance to leaf feeding damage have been developed and released. Fall armyworm and Southwestern Corn Borer larvae feeding on resistant genotypes grow more slowly than those feeding on susceptible genotypes. The objectives of the investigation were to evaluate 20 single cross maize hybrids for leaf feeding damage by southwest- ern Corn Borer and fall armyworm, to compare larval growth on laboratory diets prepared from lyophilized leaf tissue of single cross hybrids with different levels of resistance to leaf feeding, and to determine whether larval growth differed between diets prepared from leaf tissue collected from plants previously infested with Southwestern Corn Borer or fall armyworm and non- infested plants. Both fall armyworm and Southwestern Corn Borer larvae weighed significantly less when fed on laboratory diets prepared from lyophilized leaf tissue of resistant single cross hybrids than susceptible hybrids. When tissue from either resistant or susceptible plants that had been infested with either insect in the field was used in bioassays, larval weights were further reduced. It appears that both constitutive and induced defensive mechanisms may be operating.
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genetic basis of resistance to fall armyworm lepidoptera noctuidae and Southwestern Corn Borer lepidoptera crambidae leaf feeding damage in maize
Journal of Economic Entomology, 2007Co-Authors: Thomas D Brooks, Paul W Williams, Shaun B Bushman, Micheal D Mcmullen, P. M. BuckleyAbstract:Leaf-feeding damage by first generation larvae of fall armyworm, Spodopter frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), and Southwestern Corn Borer, Diatraea grandiosella Dyar (Lepidoptera: Crambidae), cause major economic losses each year in maize, Zea mays L. A previous study identified quantitative trait loci (QTL) contributing to reduced leaf-feeding damage by these insects in the maize line Mp704. This study was initiated to identify QTL and their interactions associated with first generation leaf-feeding damage by fall armyworm and Southwestern Corn Borer. QTL associated with fall armyworm and Southwestern Corn Borer resistance in resistant line Mp708 were identified and compared with Mp704. Multiple trait analysis (MTA) of both data sets was then used to identify the most important genetic regions affecting resistance to fall armyworm and Southwestern Corn Borer leaf-feeding damage. Genetic models containing four and seven QTL explained Southwestern Corn Borer and fall armyworm resistance, respectively, in Mp708. Key genomic regions on chromosomes 1, 5, 7, and 9 were identified by MTA in Mp704 and Mp708 that confer resistance to both fall armyworm and Southwestern Corn Borer. QTL regions on chromosomes 1, 5, 7, and 9 contained resistance to both insects and were present in both resistant lines. These regions correspond with previously identified QTL related to resistance to other lepidopteran insects, suggesting that broad-spectrum resistance to leaf feeding is primarily controlled by only a few genetic regions in this germplasm.
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aflatoxin accumulation in Corn hybrids infested at different growth stages with Southwestern Corn Borer lepidoptera crambidae 1
2007Co-Authors: Paul W Williams, P. M. Buckley, Gary L Windham, Christopher A DavesAbstract:Aflatoxin is a potent toxin produced by the fungus Aspergillus flavus. Contamination of Corn, Zea mays L., with aflatoxin greatly reduces the value of Corn grain and is a major impediment to profitable Corn production in the South. Infestation of developing Corn ears with Southwestern Corn Borer, Diatraea grandiosella Dyar (Lepidopera: Crambidae), increases the likelihood of aflatoxin contamination. In this investigation, six Corn hybrids with differ- ent levels of resistance to Southwestern Corn Borer damage and aflatoxin con- tamination were evaluated for damage by Southwestern Corn Borer and afla- toxin contamination after infestation with Southwestern Corn Borer at 7-d intervals from 35-84 d after planting and inoculation with an A. flavus conidial suspension. Transgenic (Bt) hybrids exhibited excellent resistance to south- western Corn Borer and less aflatoxin contamination than conventional ver- sions of the same hybrids. A conventional hybrid with intermediate resistance to Southwestern Corn Borer also exhibited relatively low levels of aflatoxin contamination. A conventional hybrid selected for resistance to aflatoxin con- tamination was heavily damaged by Southwestern Corn Borer, but exhibited little aflatoxin contamination. Hybrids that have resistance to both southwest- ern Corn Borer and aflatoxin contamination appear to have the greatest poten- tial for effectively reducing losses to aflatoxin in the South. Damage by south- western Corn Borer to plants in both the vegetative and reproductive stage so f growth can increase aflatoxin contamination in susceptible Corn hybrids.
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quantitative trait loci conferring resistance to fall armyworm and Southwestern Corn Borer leaf feeding damage
Crop Science, 2005Co-Authors: Thomas D Brooks, Paul W Williams, Martha C Willcox, P. M. BuckleyAbstract:Southwestern Corn Borer (Diatraea grandiosella Dyar) and fall armyworm [Spodoptera frugiperda (J.E. Smith)] damage ratings were measured on an F2-derived maize (Zea mays L.) population segregating for leaf feeding resistance following artificial infestation with neonates. Damage ratings for each insect were recorded in replicated trials at three locations and used in conjunction with a genetic linkage map to identify quantitative trait loci (QTL) associated with resistance. Significant QTL and their interactions were estimated by multiple interval mapping analysis. Resistance to Southwestern Corn Borer leaf feeding was fit to a model containing eight QTL and two interactions explaining 20% of the phenotypic variation. A model containing seven QTL and one interaction best fit resistance to fall armyworm leaf feeding damage, and it explained approximately 14% of the phenotypic variation. Three QTL located on chromosomes 6, 9, and 10 affect leaf feeding damage ratings of both insects with similar effects and gene action. Minor interaction effects were observed. The QTL on chromosomes 1, 5, and 9 correspond to previously identified regions affecting resistance to Southwestern Corn Borer. Insect resistance genes including the mir family of genes located on chromosome 6 and the glossylS locus on chromosome 9 fall within Chromosomal regions of QTL predicted in this study. This study confirms that resistance to fall armyworm and Southwestern Corn Borer involves many of the same QTL and candidate genes for insect resistance include the glossy 15 candidate locus on chromosome 9.
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Southwestern Corn Borer damage and aflatoxin accumulation in conventional and transgenic Corn hybrids
Field Crops Research, 2005Co-Authors: P. M. Buckley, Gary L Windham, Paul W Williams, James M PerkinsAbstract:Southwestern Corn Borer (Diatraea grandiosella Dyar) is a major pest of Corn (Zea mays L.) in the southern United States. In addition to the direct yield losses caused by Southwestern Corn Borer, larval feeding on developing ears provides a site for fungi to enter the ear. Aspergillus flavus Link: Fries infection and the subsequent accumulation of aflatoxin in Corn grain are major limitations to profitable Corn production in the southern United States. This investigation was conducted to determine the effectiveness of transgenic Corn hybrids expressing the δ-endotoxin insecticidal (CryIAb) proteins isolated from Bacillus thuringiensis (Bt) in reducing Southwestern Corn Borer damage and aflatoxin accumulation. Ear damage and aflatoxin accumulation were compared among 10 pairs of conventional nonBt and transgenic Bt Corn hybrids following infestation with Southwestern Corn Borer and inoculation with A. flavus using kernel-wounding and nonwounding techniques. Both nonBt and Bt hybrids exhibited high levels of aflatoxin accumulation when inoculated with a kernel-wounding technique. When inoculated with a non-wounding technique and infested with Southwestern Corn Borer, aflatoxin accumulation was significantly higher in nonBt than Bt hybrids. Aflatoxin accumulation was also significantly higher for nonBt hybrids inoculated with A. flavus and infested with Southwestern Corn Borer than for hybrids that were only inoculated with A. flavus. Southwestern Corn Borer larval establishment was significantly higher on nonBt hybrids than on Bt hybrids. Larval survival was extremely low on the Bt hybrids. The results of this investigation indicate that these Bt hybrids should be effective in reducing aflatoxin contamination in areas where high Southwestern Corn Borer infestations occur. The reduced levels of aflatoxin accumulation associated with Bt hybrids are likely a consequence of reduced insect damage rather than resistance to A. flavus infection or aflatoxin accumulation per se.
G.m. Chippendale - One of the best experts on this subject based on the ideXlab platform.
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Effect of a hypolipidemic agent on the growth and development of the Southwestern Corn Borer, Diatraea grandiosella
Comparative Biochemistry and Physiology Part C: Pharmacology Toxicology and Endocrinology, 1996Co-Authors: Holly J R Popham, G.m. ChippendaleAbstract:Abstract The hypolipidemic agent, 5-tetradecyloxy-2-furanocarboxylic acid (TOFA), blocks acetyl-CoA carboxylase, the rate-limiting step in the synthesis of fatty acids. We examined the effect of dietary TOFA on larval growth and development of the Southwestern Corn Borer, Diatraea grandiosella . Dietary levels of 200 and 300 ppm TOFA (wet wt) suppressed both growth and development. A reciprocal transfer experiment using the control and a 300-ppm TOFA diet showed that TOFA must be ingested throughout the larvae period to have a deleterious effect. TOFA holds promise as a tool when a block in fatty acid synthesis will add insight into insect lipid transport, use or metabolism.
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Factors regulating lipophorin synthesis by the larval fat body of the Southwestern Corn Borer, Diatraea grandiosella
Journal of Insect Physiology, 1996Co-Authors: Kent S. Shelby, G.m. ChippendaleAbstract:Abstract The effects of starvation, dietary lipid restriction, topical methoprene treatment, and diapause termination on the synthesis of lipophorin by larval fat bodies of the Southwestern Corn Borer, Diatraea grandiosella, were examined. Excised larval fat bodies were labeled in vitro with [3H]leucine and the synthesis and release of [3H]lipophorin were measured using immunochemical methods. When 9 day old larvae were transferred from control diet on to a nonnutritive agar medium, protein synthesis, including lipophorin synthesis, was inhibited two and four days later. Larvae returned to control diet regained their capacity to synthesize lipophorin. Larvae transferred to a lipid-depleted diet at 10 days of age showed no decrease in lipophorin synthesis two, 8 or 14 days later. When non-diapause 5th instar larvae were treated with methoprene to induce a diapause-like state, lipophorin synthesis and release by the fat body was intermediate between that of non-diapause and pre-diapause larvae. Late diapause larvae, immediately after being transferred to conditions that accelerated diapause termination, showed an increase in lipophorin synthesis over that of controls retained under diapause-sustaining conditions. Thus, the resumption of lipophorin synthesis precedes the onset of the pupal molting cycle, thereby making lipophorin available for lipid transport upon resumption of morphogenesis.
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Effect of dietary treatments on the lipophorin titer in the larval hemolymph of the Southwestern Corn Borer, Diatraea grandiosella
Journal of Insect Physiology, 1994Co-Authors: Holly J R Popham, G.m. ChippendaleAbstract:Abstract This study examined whether the availability of stored lipid controls the release of lipophorin from the larval fat body of the Southwestern Corn Borer, Diatraea grandiosella. The larval fat body of this insect synthesizes and releases a high-density lipophorin. Larvae transferred from a diet containing 1.22% lipid (wet wt) to a lipid-free diet at 9 days-of-age had a lipophorin titer in their hemolymph 8 days after transfer that was 2 mg/ml lower than that in larvae retained on the 1.22% lipid diet. Neonate larvae fed a diet containing 0.25% sucrose and 0.1% lipid had a lower lipophorin titer in their hemolymph at 15 days-of-age than had larvae fed a diet containing 3.25% sucrose and 0.1% lipid. Neonate larvae fed a diet containing 0.03% of the hypolipidemic agent, 5-tetradecyloxy-2-furanocarboxylic acid, and 0.24% lipid had a lower lipophorin titer in their hemolymph at 15 days-of-age than had larvae fed a diet containing no inhibitor and 0.24% lipid. In vitro incubation of fat bodies showed that the release of lipophorin, but not total protein, was inhibited by transferring fourth instars onto a lipid-free diet. Therefore, the availability of lipids for loading onto lipophorin in the fat body is one factor controlling the titer of lipophorin in the larval hemolymph of this insect.
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Measurement of the lipophorin titer in the larval hemolymph of the Southwestern Corn Borer, Diatraea grandiosella, by ELISA
Insect Biochemistry and Molecular Biology, 1993Co-Authors: Holly J R Popham, G.m. ChippendaleAbstract:Abstract An enzyme-linked immunosorbent assay (ELISA) was developed to measure the lipophorin titer in the hemolymph of the Southwestern Corn Borer, Diatraea grandiosella . Results obtained using indirect and direct ELISA methods were compared. The indirect ELISA was then used to compare the lipophorin titers in the hemolymph of non-diapause, pre-diapause, and diapause larvae. The mean lipophorin titer in the hemolymph of non-diapause larvae was 2.5 mg/ml in fourth instar larvae and increased to 3.9 mg/ml during the fifth and sixth instars. The mean lipophorin titer in the hemolymph of pre-diapause larvae was 2.3 mg/ml in 13 day old larvae and increased to 4.0 mg/ml in 22 day old larvae. The mean titer then decreased significantly until day 40, but increased to 5.1 mg/ml in 49 day old larvae after they had entered diapause and held at c . 3 mg/ml until larvae were about 70 days old, when it increased to c . 5 mg/ml and remained constant for at least the next 20 days. The amount of lipid in the hemolymph was also measured and correlated to the amount of lipophorin present.
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Characteristics of apolipophorin-III of the Southwestern Corn Borer, Diatraea grandiosella
Insect Biochemistry and Molecular Biology, 1992Co-Authors: Charles S. Burks, Kent S. Shelby, G.m. ChippendaleAbstract:Abstract Apolipophorin-III was isolated from the lipophorin-free fraction of larval plasma of the Southwestern Corn Borer, Diatraea grandiosella , because significant amounts of apolipophorin-III were found to be present in the hemolymph not associated with lipophorin. Apolipophorin-III, purified using ammonium sulfate precipitation, cation exchange chromatography, and gel filtration, was shown to be a nonglycosylated polypeptide with 17 kDa mol. wt, as determined by SDS-PAGE and silver staining. The amino acid composition of apolipophorin-III showed similarities to published compositions of apolipophorin-III isolated from other insects. The N-terminal sequence of apolipophorin-III (DAPSTTPPQDXEKKAAEFQKTFTEQXNQLANK), is highly homologous to that of apolipophorin-III of Manduca sexta . Antiserum raised against purified apolipophorin-III was used to demonstrate an immunochemical identity between the isolated apolipophorin-III and that associated with lipophorin. This antiserum cross-reacted with apolipophorin-III of M. sexta , and antiserum raised against M. sexta apolipophorin-III cross-reacted with apolipophorin-III isolated from D. grandiosella , demonstrating an immunochemical relationship between the proteins, and providing confirmatory evidence for the identity of the isolated protein. These antisera did not react with the putative apolipophorin-III of the cricket, Acheta domesticus . Using immunoprecipitation by the apolipophorin-III antiserum of D. grandiosella , the synthesis and secretion of [ 3 H]apolipophorin-III by the fat body in vitro was shown to be maximal in 13–15 day-old larvae, with a transit time of ca 23 min.
W P Williams - One of the best experts on this subject based on the ideXlab platform.
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impact of plant resistance on Southwestern Corn Borer lepidoptera crambidae biology and plant damage
Journal of Economic Entomology, 2007Co-Authors: Chris A. Daves, W P Williams, F M DavisAbstract:Southwestern Corn Borer, Diatraea grandiosella Dyar (Lepidoptera: Crambidae), is a major insect pest of Corn, Zea mays L., in the southern United States. Germplasm lines with resistance to Southwestern Corn Borer have been developed and released by the USDA-ARS. Two single-cross hybrids produced by crossing germplasm lines with resistance to Southwestern Corn Borer and a susceptible single-cross hybrid were infested with Southwestern Corn Borer larvae in a 2-yr field test conducted in Mississippi. The susceptible hybrid sustained significantly more leaf damage and stalk tunneling than either resistant hybrid. The number of tunnels and the length of tunneling were significantly lower on the resistant hybrids. In 2003, up to 15 times more tunneling was observed on the susceptible hybrid. Larvae feeding on the resistant hybrids were delayed in their movement from the whorl to the stalk and larval survival was 50% lower on the resistant hybrids than on the susceptible hybrid. Larvae recovered from the susceptible hybrid 7-14 d after infestation weighed twice as much as those recovered from the resistant hybrids. Similar differences in larval weight were observed in the laboratory when larvae were reared on diets prepared from lyophilized tissue from the three hybrids. These results provide a foundation for other investigations designed to identify and determine the roles of specific genes and gene families associated with Southwestern Corn Borer resistance in Corn.
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aflatoxin accumulation in maize after inoculation with aspergillus flavus and infestation with Southwestern Corn Borer
2003Co-Authors: W P Williams, Gary L Windham, P M Buckley, Received JulAbstract:Aflatoxin is a potent carcinogen produced by the fungus Aspergillus flavus Link: Fr. Drought, high temperatures, and insect damage are associated with high levels of aflatoxin accumulation in maize, Zea Mays L.. Plant resistance is generally considered a desirable way of reducing aflatoxin contamination. Germplasm lines with resistance to aflatoxin contamination have been developed. A nine-parent diallel cross was made using three lines with resistance to Southwestern Corn Borer; Ditraea grandiosella Dyar; three lines with resistance to aflatoxin contamination; and three lines susceptible to both aflatoxin contamination and Southwestern coin Borer. The resulting single cross hybrids were evaluated for aflatoxin contamination following inoculation with A. flavus and infestation with Southwestern Corn Borer. General combining ability (GCA) was a highly significant source of variation in the inheritance of resistance to aflatoxin contamination; specific combining ability was not significant. Estimates of GCA effects indicated that Mp3I3E and Mp92:673, lines selected for aflatoxin resistance, contributed significantl y to reduced aflatoxin contamination. Hybrids with Mp496 and Mp716, two of the Southwestern Corn Borer resistant lines, also exhibited reduced levels of aflatoxin contamination. These lines would be useful as sources of resistance in the development of maize hybrids with resistance to aflatoxin contamination.
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Southwestern Corn Borer damage and aflatoxin accumulation in a diallel cross of maize
2002Co-Authors: W P Williams, Gary L Windham, F M Davis, P M BuckleyAbstract:Southwestern Corn Borer, Diatraea grandiosella Dyar, is a serious pest of maize, Zea mays L., in the southern USA. When plants are infested during and after anthesis, larvae feed on the husks and developing cars before tunneling into the stalk. Larval feeding also provides potential sites for fungi to enter developing ears. Aflatoxin, produced by the fungus Aspergillus flavus Link: Fr, is a potent carcinogen, and its presence at levels exceeding 20 ng g restricts maize from interstate commerce. Aflatoxin contamination is a chronic problem in maize produced in the southern USA. Little is cur- rently known about the value of resistance to Southwestern Corn Borer in reducing aflatoxin accu- mulation. This investigation was undertaken to compare aflatoxin accumulation in crosses among in- bred crosses with different levels of Southwestern Corn Borer resistance and to study the importance of general and specific combining ability in the inheritance of resistance to Southwestern Corn bor- er and aflatoxin accumulation in an eight-parent diallel cross. Our results indicated that general com- bining ability was a highly significant source of variation in the inheritance of resistance to stalk tun- neling and ear damage by Southwestern Corn Borer and resistance to aflatoxin accumulation. Stalk tunneling, ear damage, and aflatoxin accumulation were lowest in hybrids with the inbred line MP496 as a parent.
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effects of the Southwestern Corn Borer on aspergillus flavus kernel infection and aflatoxin accumulation in maize hybrids
Plant Disease, 1999Co-Authors: Gary L Windham, W P Williams, F M DavisAbstract:ABSTRACT Field studies were conducted in 1995 to 1997 to determine the effect of the Southwestern Corn Borer (SWCB) on Aspergillus flavus kernel infection and aflatoxin accumulation in maize hybrids. In 1995, when A. flavus conidia were applied to silks in a spray and SWCB neonate larvae in maize cob grits were placed in the leaf axil at the top ear of commercial hybrids, aflatoxin contamination and A. flavus kernel infection were highest in plants treated with both the fungus and the insect. In 1996, using the same inoculation and infestation techniques, aflatoxin levels and kernel infection were much lower than in 1995 and SWCB had no effect on aflatoxin contamination or kernel infection. In another study in 1996, the effect of SWCB on aflatoxin contamination and A. flavus kernel infection in hybrids resistant and susceptible to A. flavus was determined. The inoculation-infestation technique involved applying maize cob grits containing A. flavus conidia and SWCB larvae to silks. When SWCB was combined w...
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growth responses of Southwestern Corn Borer lepidoptera crambidae and fall armyworm lepidoptera noctuidae larvae fed combinations of whorl leaf tissue from a resistant and a susceptible maize hybrid
Journal of Economic Entomology, 1998Co-Authors: F M Davis, W P Williams, P. M. BuckleyAbstract:Maize, Zea mays L., germplasm with resistance to leaf feeding by Southwestern Corn Borer, Diatraea grandiosella Dyar, and fall armyworm, Spodoptera frugiperda (J. E. Smith), neonates has been developed and released. Laboratory studies were conducted over 2 yr to determine if this resistance extends to older larvae initially fed susceptible leaf tissue and if larvae initially fed resistant leaf tissue recover when switched to similar susceptible tissue. Our results indicate a resistance and a recovery response by larvae of both species, depending on leaf tissue feeding regime. Southwestern Corn Borer larvae fed susceptible tissue for 3 or 7 d before switching to resistant tissue gained significantly less weight after the switch than those fed on only susceptible tissue. In contrast. Southwestern Corn Borer larvae fed resistant tissue for 3 or 7 d before switching to susceptible tissue gained significantly more weight after the switch than those fed resistant tissue only. Similar results were observed for the fall armyworm. An interesting response occurred with fall armyworm larvae fed resistant tissue after being initially fed susceptible tissue for 7 d. Although the larvae gained less weight after the tissue switch than those reared only on susceptible tissue, the number of days to pupation did not differ. However, the resulting pupae weighed only 138.5 mg compared with 182.1 mg for those reared on only susceptible tissue. Our findings provide evidence that resistance to later instars does occur in maize and useful information when considering using a mixture of resistant and susceptible seed as an integrated pest management strategy.