Michael A. Catangui

Western Bean Cutworm, Striacosta albicosta (Smith) (Lepidoptera: Noctuidae), as a Potential Pest of Transgenic Cry1Ab Bacillus thuringiensis Corn Hybrids in South Dakota

Abstract Injuries caused by the western bean cutworm, Striacosta albicosta (Smith), on transgenic Cry1Ab Bacillus thuringiensis (Bt) corn hybrids were documented and quantified. The western bean cutworm is an emerging or potential pest of transgenic Bt corn in South Dakota. The proportion of ears infested with western bean cutworm larvae in the Cry1Ab Bt corn hybrids were 18–20, 38–70, and 0–34% in 2000, 2003, and 2004, respectively. The Cry1Ab Bt corn hybrids were almost completely free of European corn borer infestations. Untreated conventional corn hybrids were less infested with western bean cutworm larvae but more infested with European corn borer larvae. The proportion of ears infested with European corn borer larvae alone were 33, 58–80, and 8–25% in 2000, 2003, and 2004, respectively. Infestations with western bean cutworm alone were 28, 8–28, and 13–19%, respectively. Proportion of ears simultaneously infested with both western bean cutworm and European corn borer larvae were much lower than single infestations by either species alone, indicating niche overlap and competition. Simultaneous infestations by the two species on untreated conventional corn hybrids were only 8, 0–18, and 0–1% in 2000, 2003, and 2004. The corn grains harvested from injured ears were also analyzed for fumonisin and aflatoxin through quantitative enzyme-linked immunosorbent assays. More mycotoxins were found in 2003 when the levels of insect infestation in the corn ears were higher than in 2004. Results from this study underscore the need to investigate other emerging or potential arthropod pests of transgenic Bt corn hybrids in addition to the western bean cutworm.

Comparison of Bacillus thuringiensis Corn Hybrids and Insecticide-Treated Isolines Exposed to Bivoltine European Corn Borer (Lepidoptera: Crambidae) in South Dakota

Abstract The performances of Bacillus thuringiensis (Bt) corn hybrids and permethrin-treated isolines were evaluated in South Dakota from 1997 to 1999. The corn hybrids were exposed to natural seasonal fluctuations of a bivoltine ecotype European corn borer population. Larval injury parameters, grain yields, and gross incomes were quantified during the 3-yr study. The use of either Bt hybrids or whorl-applied permethrin granules resulted in significant yield advantages in only 1 out of 3 yr of performance testing. Under high corn borer pressure in 1997, the performances of the Bt corn hybrids and permethrin-treated isolines were similar, and significantly better than the untreated isolines. However, injury-free corn did not necessarily translate into higher yields in some of the hybrid groups. Grain moisture at harvest, which can result in moisture penalty or dockage, was significantly higher in some Bt corn hybrids. Neither the Bt hybrids nor the permethrin-treated isolines produced significant advantages in yields in 1998 and 1999 when infestations of first-generation corn borer were almost nonexistent and infestations of second-generation European corn borers were moderate.

Recent Records of Adalia bipunctata (L.), Coccinella transversoguttata richardsoni Brown, and Coccinella novemnotata Herbst (Coleoptera: Coccinellidae) from South Dakota and Nebraska

Abstract Adalia bipunctata (L.), Coccinella transversoguttata richardsoni Brown, and C. novemnotata Herbst (Coleoptera: Coccinellidae) were previously common throughout much of North America, but their numbers have declined drastically over the last few decades. This paper reports on recent findings of these species at nine sites in western South Dakota and western Nebraska in 2008. Nine A. bipunctata, 11 C. transversoguttata richardsoni, and 12 C. novemnotata were among 930 coccinellids sampled overall. An additional C. transversoguttata richardsoni was among coccinellids captured on a sticky trap in a wheat field during survey for cereal leaf beetle, Oulema melanopus (L.), in Butte, County, South Dakota in 2000. In several instances, adult C. transversoguttata richardsoni and C. novemnotata were observed on plants with other coccinellids, especially Hippodamia convergens Guérin-Méneville, a native species, and Coccinella septempunctata L., a non-native species. Coccinella septempunctata was observed feeding upon two native aphids, Aphis helianthi Monell and Uroleucon atripes (Gillette and Palmer), providing additional records of predation by this coccinellid on non-target, native prey. Results are discussed with respect to other recent discoveries of A. bipunctata, C. transversoguttata richardsoni, and C. novemnotata and in relation to future research and conservation efforts.

Method for Continuously Rearing Coccinella Lady Beetles (Coleoptera: Coccinellidae)

Coccinella novemnotata L., the ninespotted lady beetle, and Coccinella transversoguttata richardsoni Brown, the transverse lady beetle, are predatory species whose abundance has declined significantly over the last few decades in North America. An ex situ system for continuously rearing these two beetles is described here to aid conservation efforts and facilitate studies aimed at determining factors in their decline and possible recovery. All rearing of lady beetles was conducted in the laboratory at or near room temperatures and 16:8 L:D photoperiod. The two coccinellid species were each reared separately, and different life stages were handled independently. Eggs were collected every 1 to 2 d and placed in holding containers, and individual clutches were transferred to cages with prey when their eggs began to hatch. Neonate larvae were fed live bird cherry-oat aphids (Rhopalosiphum padi (L.)) for 3 to 4 d, and second instars were trans- ferred to different cages and fed live pea aphids (Acyrthosiphon pisum (Harris)). Third and fourth instars were also fed pea aphids, but reared individually in small cups to preclude cannibalism. Upon pupation, individuals were collectively trans- ferred to fresh cups and placed in a different container for the duration of pupation. Newly emerged adults were collected within containers about 2 d after eclosion. Adults were housed in cages stocked with live pea aphids, supplemental food, and rumpled paper towels as oviposition substrate. Over 80% of egg clutches were deposited by beetles on rumpled paper towels versus other surfaces within cages, and incidence of cannibalism of egg clutches was greatly reduced on rumpled paper towels. Techniques for successful rearing of these two coccinellids and future research regarding adaptations to fur- ther optimize their rearing methods are discussed.

Nitrogen Fixation, Ureide, and Nitrate Accumulation Responses to Soybean Aphid Injury in Glycine max

ABSTRACT There is little information available about soybean aphid (Aphis glycines Matsumura) effects on the physiology and mineral nutrition of soybean (Glycine max [L.] merr.). Controlled-environment studies were conducted to measure soybean aphid infestation effects on dry weight, nitrogen (N) fixation, ureide-N, and nitrate-N concentration and accumulation. Plants grown in perlite using –N nutrient solution culture were infested at the 3rd trifoliolate (V3) stage and measured for N fixation, nodule characteristics, and ureide-N concentration at the full pod (R4) stage. When compared to uninfested control plants, aphid infestation reduced total nodule volume per plant by 34%, nodule leghemoglobin per plant by 31%, plant N fixation rate by 80% and shoot ureide-N concentration by 20%. Soil-grown plants were infested at the first trifoliolate (V1) stage and shoots were measured for dry weight, nitrate-N, and ureide-N at the full bloom (R2) stage. Infestation reduced shoot dry weight by 63%, increased nitrate-N concentration by 75%, but did not significantly affect ureide-N concentration. Because nutrient concentration is a single-point measurement that results from the integration of two dynamic processes, nutrient accumulation and dry matter production, we conclude that aphid-induced reductions in N fixation, coupled with decreased dry weight accumulation, caused shoot ureide-N concentration to remain unchanged in aphid-injured plants when compared to uninfested plants. Because nitrate-N concentration was greater in aphid-damaged shoot tissue, we further conclude that nitrate-N accumulation was less sensitive to aphid injury than dry weight accumulation.

Lady Beetle Assemblages (Coleoptera: Coccinellidae) in Western South Dakota and Western Nebraska and Detection of Reproducing Populations of Coccinella novemnotata

ABSTRACT Recent detections of adults of three previously common, native species of lady beetles [Coccinella novemnotata Herbst, Coccinella transversoguttata richardsoni Brown, and Adalia bipunctata (L.); Coleoptera: Coccinellidae] during surveys at several sites in western South Dakota and western Nebraska provided impetus for additional sampling of lady beetles in that region. The current study systematically sampled for lady beetles among three dominant habitats in the region in 2010 and 2011. Four techniques (sucrose-baited and nonbaited yellow sticky traps, sweepnetting, visual searches) sampled 4,036 adult and 830 larval coccinellids comprising 10 species. Coccinella septempunctata L., Hippodamia convergens Guerin-Meneville, Hippodamia parenthesis (Say), and Brachiacantha albifrons (Say) were the most common species. C. novemnotata ranked fifth in abundance, with 94 sampled in small grains, 20 in alfalfa, and 5 in grassland pasture; 58 larval C. novemnotata were sampled primarily in small-grain fields. Abundance of C. novemnotata negatively correlated with proportion of vegetative cover in fields, whereas this characteristic did not correlate with abundances of H. convergens, H. parenthesis, and C. septempunctata. Abundance of these three species negatively correlated with vegetative species richness and diversity in fields, whereas C. novemnotata abundance was not related to these indices. Fourteen C. transversoguttata richardsoni, 30 C. novemnotata, and several other coccinellids were observed on roadside vegetation near sample fields. A. bipunctata was not sampled in this study. Results suggest that sparsely vegetated small-grain fields may favor reproducing populations of C. novemnotata in relatively arid areas of the north central United States.

Coccinellidae (Coleoptera) of South Dakota: New State Record for Anatis lecontei Casey and Erratum to Delete Hyperaspis fimbriolata Melsheimer

We recently published an updated list of the Coccinellidae (Coleoptera) of South Dakota (Hesler and Kieckhefer 2008). Since then, we recorded Anatis lecontei Casey, 1899 for the first time in the state, and also noticed that we had mistakenly listed Hyperaspis fimbriolata Melsheimer, 1847 as recorded from South Dakota. In this paper, we provide collection information to add A. lecontei to the list of South Dakota Coccinellidae and an erratum to delete H. fimbriolata from the list. The number of species of Coccinellidae recorded from South Dakota remains at 79, with no net change from the addition of A. lecontei and deletion of H. fimbriolata. NewStateRecord. Anatis leconteiCasey(Coccinellinae: Coccinellini). Fall River County, South Dakota, 6 mi. south of Provo, 6-VII-2009, collectors Amy Mesman and Cheryl Huddleston. The beetle has been retained as a voucher specimen in the insect collection at the USDA-ARS North Central Agricultural Research Laboratory (NCARL). The specimen was found along a gravel road in an arid area dominated by short-grass prairie and rangeland. No prey was associated with the beetle when it was found. Anatis lecontei is distributed throughout the greater Rocky Mountain region of the United States and Canada (Gordon 1985), and Michels (1987) reported A. lecontei from Sheridan and Laramie counties in Wyoming, which are roughly 200 km from the collection site in South Dakota. Thus, the record of A. lecontei in South Dakota represents an eastward extension of its previously known distribution. Erratum. Hyperaspis fimbriolata fimbriolata Melsheimer is a junior synonym of Hyperaspis inflexa Casey, 1899, a species widely distributed in the United States and Canada (Gordon 1985), including South Dakota (as H. fimbriolata fimbriolata; Kirk and Balsbaugh 1975). In contrast, Hyperaspis fimbriolata Melsheimer has only been recorded from the eastern United States (Gordon 1985). However, we mistakenly listed some specimens of H. inflexa as H. fimbriolata in our updated list of South Dakota Coccinellidae (Hesler and Kieckhefer 2008), and H. fimbriolata should be deleted from the list. The corrected entry forH. inflexa in South Dakota follows. Hyperaspis inflexa Casey (Scymninae: Hyperaspidini). Butte, Deuel, Harding, Hughes, Lawrence, Turner, Yankton. Specimens we examined are housed at NCARL, North Dakota State University Insect Collection (NDSU), Severin-McDaniel Insect Collection, South Dakota State University (SDSU), and in the personal collection of RWK. Matthew Brust, Wade French, Eric Beckendorf, and Lauren Hesler graciously reviewed drafts of this paper.