Field Crop Insect Pest Problems in North Dakota

Non-Peer Reviewe

Karshomyia caulicola (Diptera: Cecidomyiidae) Associated with Sclerotinia-Infected Soybean in the United States and Canada

The white-mold gall midge, Karshomyia caulicola Coquillett, was documented in association with soybean, Glycine max (L.) Merr., infected with the fungus Sclerotinia sclerotiorum (Lib.) de Bary. This mycetophagous cecidomyiid appears widespread in the northern soybean producing region, with confirmed detections from Minnesota, North Dakota and Québec. Though likely not a pest of soybean plants, the presence of K. caulicola in soybean fields may complicate identification, population assessment and decision making for soybean gall midge, Resseliella maxima Gagné, which is a recently described pest of soybean. Here, we provide an overview of the known biology and distribution of K. caulicola and descriptions to aid in distinguishing these two cecidomyiids

Pollinators and Other Insect Visitations on Native and Ornamental Perennials in Two Landscapes

Many pollinator insects, especially honey bees [Apis mellifera Linnaeus (Apidae)] and wild bees, are experiencing population decline because of forage and habitat losses. Planting perennial flowering taxa is one method of increasing pollinator habitat. The objectives of this study were to evaluate the potential of 27 native species and ornamental perennial cultivars to determine their ability to attract insect pollinators in a rural and an urban landscape in North Dakota, assess the potential of these perennials to attract other beneficial insects and insect pests, and identify the bee species visiting these perennials. Five to eight native species and/or ornamental cultivars each from four genera, Monarda L. (bee balm), Hylotelephium H. Ohba (stonecrop), Baptisia Vent. (wild indigo), and Symphyotrichum Nees (aster), were tested. Weekly observations of individual plants during flowering and their pollinator visitations from 2018 to 2020 indicated that insect pollinators were present for the earliest flowering perennials in June and until the latest flowering perennials during the second week of October or the first freeze. A total of 16,194 insect pollinators were observed, and 87.8% of these pollinator visitations were Hymenoptera and Diptera. Significant landscapes × perennial flowering taxa interactions were detected for all insect groups, except for syrphid flies, for which both main effects were significantly different. Overall, honey bees and beetles preferred to visit Hylotelephium and Symphyotrichum. The wild bees, lepidopterans, and syrphids preferred Hylotelephium, Symphyotrichum, and Monarda. Tachinids preferred Symphyotrichum. Blow flies preferred Hylotelephium. More beneficial insect visitations (i.e., 96.0%) and fewer insect pest visitations (i.e., 30.4%) were counted on the rural landscape. A total of 3311 bee individuals were identified as species from the following families: Apidae, Andrenidae, Colletidae, Megachilidae, and Halictidae. Thirty-one and 21 bee species were unique to the rural and urban landscapes, respectively. The two most common wild bees were Ceratina calcarata Robertson on the cultivar S. oblongifolium (Nutt.) G.L. Nessom October Skies and Lasioglossum imitatum (Smith) on some Monarda and Hylotelephium. These findings suggest that pollinator visitations are influenced by the landscape and varied among the perennial flowering taxa in some cases. However, all evaluated perennial flower taxa would be suitable for attracting and supporting pollinators in rural or urban landscape settings in the northern Great Plains

Geographic Distribution and Effects of Transgenic Corn Hybrids and Chemical Insecticides on Northern and Western Corn Rootworms (Coleoptera: Chrysomelidae) in North Dakota

Northern (Diabrotica barberi Smith & Lawrence) and western (D. virgifera virgifera LeConte) corn rootworms are major corn (Zea mays L.) pests in North America. Integrated pest management (IPM) strategies used for corn rootworm control include crop rotation, chemical insecticides, and corn hybrids expressing Bacillus thuringiensis (Bt) toxins. Field and laboratory experiments were conducted between July 2013 and October 2017 to address the following objectives: 1) determine the geographic distribution and densities of D. barberi and D. v. virgifera in North Dakota (ND) and compare the effectiveness of unbaited green ScentryTM Multigard and yellow Pherocon® AM/NB sticky traps for monitoring both species; 2) access the impacts of corn hybrids expressing the Cry3Bb1, Cry34/35Ab1, and Cry3Bb1 + Cry34/35Ab1 proteins, tefluthrin soil insecticide, and clothianidin insecticidal seed treatment on beetle emergence, larval feeding injury, and corn grain yield; and 3) evaluate if either species has developed resistance to these Bt-proteins. Both species were commonly distributed in east-central and southeastern ND, and capture rates ranged from 0 to >10 beetles per trap per week. Green ScentryTM sticky traps captured greater mean numbers of D. barberi beetles in 68% of fields containing this species, while the yellow Pherocon AM/NB trap captured higher mean numbers of D. v. virgifera in 57% of fields containing this species, but their relative trap efficiency was inconclusive. Overall beetle emergence was significantly lower in Bt-protected than in non-Bt corn. Bt hybrids produced higher grain yield and sustained consistently lower levels of larval root-feeding injury than non-Bt in fields with higher rootworm densities. Tefluthrin and clothianidin did not significantly impact beetle emergence or larval root injury. Results also documented the first confirmed field-evolved incomplete resistance in D. barberi populations to Cry3Bb1 and Cry34/35Ab1 proteins. The Ransom population of D. v. virgifera was confirmed as resistant to the Cry3Bb1 toxin. Theses findings indicate reduced efficacy of corn rootworm control using tefluthrin, clothianidin, and Bt corn. Continuously scouting for rootworms using sticky traps or other methods prior to making rootworm management decisions, and the use of an IPM approach to their control is needed to mitigate the development of Bt-resistance rootworms in ND.North Dakota Corn Utilization CouncilNational Institute of Food and Agriculture, U.S. Department of Agriculture, Hatch project accession no. 022320

Biological and Agronomic Aspects of Two Insect Predators of Switchgrass

Switchgrass (Panicum virgatum L.) is considered a potential model for an alternative fuel source in North America. Recently, two insect pests of switchgrass have been identified. The switchgrass moth [Blastobasis repartella (Dietz): Lepidoptera: Coleophoridae] feeds in the basal internodes and in rhizomes, causing premature tiller and rhizome loss. The switchgrass midge (Chilophaga virgati Gagné: Diptera: Cecidomyiidae) feeds above the last internode of the tiller, causing seed yield and biomass loss. There were two objectives for this study: (1) to determine genetic and temporal variation among cultivars for frequency of tiller infestation by switchgrass moth larvae in mature stands in the northern Great Plains and if variation in biomass production was associated with variation in frequency of infestation, in two trials (plots/established in 2004 and 2008) and (2) to increase knowledge of the biology of the gall midge by describing its life stages, phenology, and parasitoids in the Northern Great Plains. Data collection and observations were made during 2011 and 2012. In plots from 2008, differences were found among cultivars for tiller density, biomass yield, and numbers of leaves per healthy and infested tillers. Mean frequency of infestation was different between 2011 (6.7%) and 2012 (9.6%). Regression of biomass on frequency of infestation showed negative linear relationships for `Carthage’ and `Kentucky 1625’. However, in plots from 2008, differences were found among cultivars for tiller density and numbers of leaves per healthy. Mean frequency of infestation ranged from 2.6% for `Cave-In-Rock’ to 4.5% for `Pathfinder’ and was different between 2011 (2.7%) and 2012 (4.4%). In general, infested tillers had 1 less collared leaf than healthy tillers. Weights of healthy tiller were more \u3e3x those of infested tillers. Switchgrass gall midge adult is active from early June to mid/late July. It overwinters as a late instar larva. The number of larvae ranged from 6 to 85. `Cave-In-Rock’ was more infested (\u3e2x) than `Dacotah’ m-2. New parasitoids were reared from switchgrass gall midge larva: Quadrastichus sp. (Hymenoptera: Eulophilidae) and Platygaster chilophagae Buhl (Hymenoptera: Platygastridae). Results of this study are valuable to scientists for optimizing seed and biomass yields of switchgrass

The Switchgrass Gall Midge (Chilophaga virgati Gagné) in the Northern Great Plains

Switchgrass (Panicum virgatum L.) is considered to be a highly promising bioenergy crop.However, little is known about insect pests that impact its utilization for this purpose. The switchgrass gall midge [Chilophaga virgati Gagné (Diptera: Cecidomyiidae)], which was first discovered in 2008 at Brookings, SD, USA, is shown to have a negative impact on biomass and seed yields of switchgrass. Our objectives were to increase knowledge of the biology of the midge by describing its life stages and any parasitoids that have biological control potential. Data collections were made during May to December in 2011 and April to late autumn in 2012. The gall midge adult is active from early June to late July. This insect overwinters as a late instar larva, usually in large aggregations, enclosed in the sheath of the flag leaf of dry tillers. The mean number of larvae was 31, with a range of 6 to 85 per tiller. Infested tillers m−2 varied among three phenologically distinct cultivars. The late flowering cultivar ‘Cave-In-Rock’ was more heavily infested (\u3e2×) than the early flowering ‘Dacotah’. A newly discovered parasitoid, Platygaster chilophagae Buhl (Hymenoptera: Platygastridae) and a species of Quadrastichus sp. (Hymenoptera: Eulophidae) were reared from gall midge larvae. These results will be valuable to entomologists, switchgrass breeders, and agronomists as a guide to the occurrence and activities of the gall midge

First host-plant record for Leptodictya (Hanuala) leinahoni (Kirkaldy, 1905) (Hemiptera: Heteroptera: Tingidae)

Guadua weberbaueri Plig. [Poaceae] is recorded as the first host-plant record for Leptodictya (Hanuala) leinahoni (Kirkaldy). We observed eggs, nymphs, adults, and feeding injury on stands of Guadua weberbaueri, several kilometers north of the city of Caranavi, Bolivia

A new species of Platygaster Latreille (Hymenoptera: Platygastridae) parasitizing Chilophaga virgati Gagné (Diptera: Cecidomyiidae)

Johnson, Paul J., Buhl, Peter Neerup, Torrez, Veronica Calles (2013): A new species of Platygaster Latreille (Hymenoptera: Platygastridae) parasitizing Chilophaga virgati Gagné (Diptera: Cecidomyiidae). Zootaxa 3630 (1): 184-190, DOI: http://dx.doi.org/10.11646/zootaxa.3630.1.