Publications

development of soybean aphid (homoptera: aphididae) on its primary overwintering host, rhamnus cathartica.	thermally dependent development of soybean aphid (aphis glycines matsumura) and common buckthorn (rhamnus cathartica l.) were examined in growth chambers in spring 2005. models based on ambient air temperatures for all development events were developed. adjusted models were developed to account for heat units acquired because of solar radiation. these models were tested at field sites in guelph and ridgetown, ontario, canada. it was found that egg hatch of aphids and bud swell of buckthorn coinc ...	2007	18284720
insect growth regulator effects of azadirachtin and neem oil on survivorship, development and fecundity of aphis glycines (homoptera: aphididae) and its predator, harmonia axyridis (coleoptera: coccinellidae).	aphis glycines matsumura, an invasive insect pest in north american soybeans, is fed upon by a key biological control agent, harmonia axyridis pallas. although biological control is preferentially relied upon to suppress insect pests in organic agriculture, approved insecticides, such as neem, are periodically utilized to reduce damaging pest populations. the authors evaluated direct spray treatments of two neem formulations, azadirachtin and neem seed oil, under controlled conditions for effect ...	2008	18247318
sugar feeding by the aphid parasitoid binodoxys communis: how does honeydew compare with other sugar sources?	parasitoids commonly forage in agricultural settings where the predominant sugar source is homopteran honeydew. the aphidiine braconid, binodoxys communis, is an asian parasitoid currently being released against the soybean aphid, aphis glycines, in north american soybean fields. we conducted a number of laboratory experiments evaluating the quality of a. glycines honeydew as a sugar source for this parasitoid. wasps readily fed on droplets of a. glycines honeydew, honey and 50% sucrose solution ...	2008	18190926
ssr marker diversity of soybean aphid resistance sources in north america.	the soybean aphid (aphis glycines matsumura) has become a major pest of soybean in north america since 2000. seven aphid resistance sources, pi 71506, dowling, jackson, pi 567541b, pi 567598b, pi 567543c, and pi 567597c, have been identified. knowledge of genetic relationships among these sources and their ancestral parents will help breeders develop new cultivars with different resistance genes. the objective of this research was to examine the genetic relationships among these resistance sourc ...	2007	18059538
chlorophyll loss caused by soybean aphid (hemiptera: aphididae) feeding on soybean.	the soybean aphid, aphis glycines matsumura (hemiptera: aphididae), is a worldwide pest of soybean, glycine max (l.) merr. studies to find control methods were initiated in 2000 when it was first detected in north america. a. glycines can reduce yields by as much as 50%, and it is the vector of several viral diseases. a. glycines removes phloem sap, which can result in a reduction of chlorophyll content. quantification of chlorophyll loss caused by a. glycines feeding on soybean is of vital impo ...	2007	17972645
resistance to aphis glycines (hemiptera: aphididae) in various soybean lines under controlled laboratory conditions.	the soybean aphid, aphis glycines matsumura (hemiptera: aphididae), a pest of soybean, glycine max (l.) merr., native to asia, has recently become a principal pest of this crop in many areas of north america. insecticides are currently used to manage a. glycines, but host plant resistance is a potential alternative management tool. tests were conducted to determine resistance to a. glycines among soybean lines. 'cobb,' 'tie-feng 8,' and 'jackson' were resistant to population growth of a. glycine ...	2007	17849903
population dynamics of soybean aphid and biotic mortality at the edge of its range.	the soybean aphid, aphis glycines matsumura, was introduced to north central north america from asia in 2000, and it has become a major pest of soybean, glycine max (l.) merr. understanding how natural enemies impact aphid populations in the field is an important component in developing a comprehensive management plan. we examined the impact of naturally occurring predators in the field by using exclusion cages during july-august 2004 and 2005. field cages of different mesh diameters were used t ...	2007	17849879
economic threshold for soybean aphid (hemiptera: aphididae).	soybean aphid, aphis glycines matsumura (hemiptera: aphididae), reached damaging levels in 2003 and 2005 in soybean, glycine max (l.) merrill, in most northern u.s. states and canadian provinces, and it has become one of the most important pests of soybean throughout the north central region. a common experimental protocol was adopted by participants in six states who provided data from 19 yield-loss experiments conducted over a 3-yr period. population doubling times for field populations of soy ...	2007	17849878
tracking the role of alternative prey in soybean aphid predation by orius insidiosus: a molecular approach.	the soybean aphid, aphis glycines (hemiptera: aphididae), is a pest of soybeans in asia, and in recent years has caused extensive damage to soybeans in north america. within these agroecosystems, generalist predators form an important component of the assemblage of natural enemies, and can exert significant pressure on prey populations. these food webs are complex and molecular gut-content analyses offer nondisruptive approaches for examining trophic linkages in the field. we describe the develo ...	2007	17784913
antagonistic effects of soybean viruses on soybean aphid performance.	although there is long-standing recognition that pest complexes require different management approaches than individual pests, relatively little research has explored how pests interact. in particular, little is known of how herbivorous insects and plant pathogens interact when sharing the same host plant. the soybean aphid, aphis glycines mastumura, a recently introduced pest of soybean in the upper midwestern united states, and a complex of plant viruses vectored to soybean by insects have bec ...	2007	17716484
population dynamics of aphis glycines (homoptera: aphididae) and impact of natural enemies in northern china.	field surveys of soybean aphid, aphis glycines matsumura, and its natural enemies, as well as natural enemy exclosure experiments, were conducted during 2003 and 2004 in soybean fields near langfang, china. in 2003, aphid density increased six-fold during 12 d in july from 66+/-12 per 10 plants to a seasonal peak of 401+/-79 per 10 plants. aphid density remained high for another 10 d and declined during late july and early august. in 2004, aphid density increased 29-fold during 13 d in july from ...	2007	17716474
molecular phylogenetics and reproductive incompatibility in a complex of cryptic species of aphid parasitoids.	we infer the phylogeny of a complex of cryptic species and populations of parasitic wasps and examine how reproductive incompatibility maps onto the molecular phylogeny. we used four nuclear (28s-d2, its1, its2, argk) and two mitochondrial (coi, coii) gene regions to analyze relationships among populations in the aphelinus varipes species complex (hymenoptera: aphelinidae) from throughout eurasia (france, georgia, israel, china, korea and japan) and from three aphid hosts (aphis glycines, diurap ...	2007	17702609
feeding behavior by the soybean aphid (hemiptera: aphididae) on resistant and susceptible soybean genotypes.	the soybean aphid, aphis glycines matsumura (hemiptera: aphididae), is a major pest of soybean, glycine max (l.) merr. since 2000, when a. glycines was detected in the united states, several studies on this insect have been done in different areas, but there is no report of any studies of stylet penetration behavior by a. glycines on resistant and susceptible soybean. assessment of feeding behavior of this aphid species was compared on four resistant entries (k1639, pioneer 95b97, dowling, and j ...	2007	17598565
decline of soybean aphid (homoptera: aphididae) egg populations from autumn to spring on the primary host, rhamnus cathartica.	soybean aphid, aphis glycines matsumura (homoptera: aphididae), is a severe pest of soybeans in north america. soybean aphid populations cycle between a secondary summer host, where populations reproduce parthenogenetically and a primary host, where populations overwinter as eggs. in north america, the secondary host is soybean, and the primary hosts are rhamnus cathartica l. (rhamnaceae) and r. alnifolia l'her. a location with abundant populations of soybean aphid on r. cathartica was identifie ...	2007	17540062
suppression of soybean aphid by generalist predators results in a trophic cascade in soybeans.	top-down regulation of herbivores in terrestrial ecosystems is pervasive and can lead to trophic cascades that release plants from herbivory. due to their relatively simplified food webs, agroecosystems may be particularly prone to trophic cascades, a rationale that underlies biological control. however, theoretical and empirical studies show that, within multiple enemy assemblages, intraguild predation (igp) may lead to a disruption of top-down control by predators. we conducted a factorial fie ...	2007	17489251
alfalfa living mulch advances biological control of soybean aphid.	despite evidence for biological control in north america, outbreaks of the invasive soybean aphid, aphis glycines matsumura (hemiptera: aphididae), continue to occur on soybean (glycine max l. merr.). our objectives were to determine whether natural enemies delay aphid establishment and limit subsequent population growth and whether biological control can be improved by altering the within-field habitat. we hypothesized that a living mulch would increase the abundance of the aphidophagous commun ...	2007	17445377
soil potassium deficiency affects soybean phloem nitrogen and soybean aphid populations.	the soybean aphid is an invasive pest in the midwest united states, with frequent population outbreaks. previous work has shown that aphid population densities are higher on potassium-deficient soybean than on healthy soybean. the experiments reported here test the hypotheses that the potassium nutrition of the host plant affects the forms of phloem nitrogen available to soybean aphids, and subsequently, their abundance. in field surveys and an exclusion cage study when aphid populations were hi ...	2007	17349112
characterization of antibiosis and antixenosis to the soybean aphid (hemiptera: aphididae) in several soybean genotypes.	the soybean aphid, aphis glycines matsumura (hemiptera: aphididae), is an introduced pest of soybean, glycine max (l.) merr., in north america, and it can reduce yields by 50%. since 2000, when a. glycines was first detected in the united states, studies of this insect and possible control methods have been initiated. plant resistance to this aphid species is one important component of integrated control. reproduction of a. glycines was compared on 240 soybean entries in a pesticide-free greenho ...	2006	17066826
predators exert top-down control of soybean aphid across a gradient of agricultural management systems.	the discovery of soybean aphid, aphis glycines matusumura, in north america in 2000 provided the opportunity to investigate the relative strength of top-down and bottom-up forces in regulating populations of this new invasive herbivore. at the kellogg biological station long term ecological research site in agroecology, we contrasted a. glycines establishment and population growth under three agricultural production systems that differed markedly in disturbance and fertility regimes. agricultura ...	2006	16937822
toxicity of indoxacarb and spinosad to the multicolored asian lady beetle, harmonia axyridis (coleoptera: coccinellidae), via three routes of exposure.	the use of selective insecticides may improve conservation of natural enemies and therefore contribute to the success of integrated pest management (ipm) programs. in this study, the toxicity of two commonly used selective insecticides, indoxacarb and spinosad, to the multicolored asian lady beetle, harmonia axyridis (pallas), was evaluated. third instars and adults of h. axyridis were exposed to indoxacarb at 50 and 100% of the field rate (fr), to spinosad at 100% fr and to water (untreated che ...	2006	16794989
soybean plant stage and population growth of soybean aphid.	the soybean aphid, aphis glycines matsumura, is a newly invasive species of aphid in north america. previous studies disagree as to whether soybean, glycine max (l.) merr., plant stage has an impact on aphid intrinsic rate of increase. therefore, the growth rate of soybean aphids on soybean plants of different stages was examined at two different scales in the field. a planting date experiment was used to measure the population growth of soybean aphids on plants of different stages. clip-cages w ...	2006	16573324
determining the optimal timing of foliar insecticide applications for control of soybean aphid (hemiptera: aphididae) on soybean.	field experiments were performed over 3 yr to examine the impact of insecticide application timing to control soybean aphid, aphis glycines matsumura (hemiptera: aphididae), populations and to prevent soybean yield losses. experiments were conducted in early and late-planted soybean, glycine max (l.) merr. insecticide applications were made based on soybean growth stages. in 2001, applications were made at v1, v3, r2, and r3 growth stages; in 2002 and 2003, applications were made at r2, r3, and ...	2005	16539126
changes in delta 13c stable isotopes in multiple tissues of insect predators fed isotopically distinct prey.	traditionally, researchers have used measurements of carbon stable isotopes to infer the composition of consumers' diets. however, since consumer's tissues may process carbon isotopes differently, particularly following a diet shift, it is possible to use measurements of carbon isotopes in multiple tissues to determine not only the composition of an individual's diet, but also the temporal dynamics thereof. this study examined how stable isotopes of carbon (13c/12c, expressed as delta 13c) chang ...	2006	16341886
methyl salicylate, a soybean aphid-induced plant volatile attractive to the predator coccinella septempunctata.	induced volatiles provide a signal to foraging predatory insects about the location of their prey. in iowa, early in the growing season of soybean, glycine max, many predacious seven-spotted lady beetles, coccinella septempunctata, were observed on plants with heavy infestations of soybean aphid, aphis glycines. we studied whether the attraction of this beetle is caused by the release of specific volatile compounds of soybean plants infested by aphids. volatile compounds emitted by soybean plant ...	2005	16222805
forecasting seasonal population growth of aphis glycines (hemiptera: aphididae) in soybean in illinois.	from 2001 to 2004, 252 fifty-plant samples were collected from commercial soybean, glycine max l., fields in three townships (93-km2 area) in illinois. townships were sampled every 3 wk from late june or early july when aphids (aphis glycines matsumura) first invaded the townships to early august. we used linear regression of 18 mean township field densities to calibrate several simple models to predict the change in aphid population density in a township from one sampling date to the next. the ...	2005	16156566
effect of soil potassium availability on soybean aphid (hemiptera: aphididae) population dynamics and soybean yield.	studies were conducted to examine the effect of potassium (k) on soybean aphid, aphis glycines matsumura, population growth. a laboratory feeding assay examined the effect of k-deficient foliage on life table parameters of soybean aphids, and field experiments were designed to determine the effect of three soil k treatment levels on aphid populations and their impact on soybean yields. the feeding assay found that life table parameters differed between aphids feeding on the k-deficient and nonde ...	2005	15765672
enumerative and binomial sequential sampling plans for soybean aphid (homoptera: aphididae) in soybean.	since the discovery of the soybean aphid, aphis glycines matsumura, in midwestern u.s. soybean, glycine max l., in 2000, the aphid has become a significant economic pest. basic information about estimating population density within fields is unknown. therefore, we developed two sampling plans to efficiently characterize a. glycines densities. enumerative and binomial sequential plans were developed using 89 data sets collected from 10 commercial fields sampled during 2001-2003. re-sampling softw ...	2004	15666774
effect of three resistant soybean genotypes on the fecundity, mortality, and maturation of soybean aphid (homoptera: aphididae).	the fecundity, longevity, mortality, and maturation of the soybean aphid, aphis glycines matsumura (homoptera: aphididae), were characterized using three resistant soybean, glycine max (l.) merrill, genotypes ('dowling', 'jackson', and pi200538 'sugao zarai') and two susceptible genotypes ('pana' and 'loda'). antibiosis in the resistant genotypes was demonstrated by a significant decrease in fecundity and longevity and increased mortality of a. glycines. aphid fecundity, measured as number of of ...	2004	15279297
resistance of glycine species and various cultivated legumes to the soybean aphid (homoptera: aphididae).	the soybean aphid, aphis glycines matsumura, is a new pest of soybean, glycine max (l.) merr., in north america. it has become widespread on soybean in north america since it was first identified in the midwest in 2000. species of rhamnus l. (buckthorn) are the primary hosts of a. glycines, and soybean is known as a secondary host. there is limited information about the secondary host range of a. glycines. aphid colonization on various legume hosts was compared in choice experiments. aphid colon ...	2004	15279293
demography of soybean aphid (homoptera: aphididae) at summer temperatures.	soybean aphid, aphis glycines matsumura, is now widely established in soybean, glycine max l., production areas of the northern united states and southern canada and is becoming an important economic pest. temperature effect on soybean aphid fecundity and survivorship is not well understood. we determined the optimal temperature for soybean aphid growth and reproduction on soybean under controlled conditions. we constructed life tables for soybean aphid at 20, 25, 30, and 35 degrees c with a pho ...	2004	15279264
comparing greenhouse sprayers: the dose-transfer process.	three sprayers were evaluated for their affect on retention and efficacy: a carbon dioxide powered high-volume sprayer, a dramm coldfogger, and an electrostatic spraying systems (ess) sprayer with air-assistance. the active ingredients used were spinosad and azadirachtin. the plant canopy was constructed in the greenhouse using potted soybeans (glycine max (l) merrill cr pioneer 9392). application efficacy with spinosad was assessed using thrips [western flower thrips, frankliniella occidentalis ...	2004	15154520
variability and transmission by aphis glycines of north american and asian soybean mosaic virus isolates.	the variability of north american and asian strains and isolates of soybean mosaic virus was investigated. first, polymerase chain reaction (pcr) products representing the coat protein (cp)-coding regions of 38 smvs were analyzed for restriction fragment length polymorphisms (rflp). second, the nucleotide and predicted amino acid sequence variability of the p1-coding region of 18 smvs and the helper component/protease (hc/pro) and cp-coding regions of 25 smvs were assessed. the cp nucleotide and ...	2003	14551816
photosynthetic responses of soybean to soybean aphid (homoptera: aphididae) injury.	the soybean aphid, aphis glycines matsumara, was discovered in the united states in the summer of 2000. since that initial discovery, the aphid has spread across northern soybean production regions. in 2001, we examined the physiological responses of soybeans to low aphids densities (fewer than 50 aphids/leaf). in this study, we determined photosynthetic rates, leaf fluorescence responses, and photosynthetic responses to variable carbon dioxide and light levels. in addition, analyses for chlorop ...	2003	12650361
bionomics of scymnus (pullus) louisianae j. chapin (coleoptera: coccinellidae) as a predator of the soybean aphid, aphis glycines matsumura (homoptera: aphididae).	a field population of scymnus louisianae chapin (coccinellidae) was found attacking soybean aphids, apis glycines matsumura (aphidae), a pest recently introduced into kentucky. this coccinellid had not previously been found in kentucky. a greenhouse population of s. louisianae was established and its predation on a. glycines studied under laboratory conditions. total time to develop from egg to adult was about 20 d. about 70% of immatures survived to adulthood and they consumed approximately 100 ...	2003	12650339