Grass Hosts of Cereal Aphids (Hemiptera: Aphididae) Between Wheat-Cropping Cycles in South Dakota

Several grasses may serve as alternative hosts for cereal aphids during the interim between small-grain crops in South Dakota, but field studies to determine which grasses are important have not been undertaken. We sampled annual and perennial grasses for cereal aphids in 18 counties in South Dakota in the month of August over three years. Eighty-five of 240 site samples had one or more species of cereal aphids, including 61 of 65 corn sites and 12 of 13 sorghum and sudangrass sites. Four species of cereal aphids were found during the survey: corn leaf aphid, 74 times; bird cherry-oat aphid, 27 times; greenbug, eight times; and English grain aphid, seven times. Abundance of corn leaf aphid on host plants was rated high seven times, moderate 11 times, and low 50 times, and presence only was noted at six other sites. Abundance of bird cherry-oat aphid was rated high four times, moderate four times, and low 19 times. Abundance of English grain aphid and greenbug was always rated low. All high ratings of corn leaf aphid and of bird cherry-oat aphid occurred on field corn. Nine moderate ratings for corn leaf aphid and three for bird cherry-oat aphid occurred on corn. Low frequencies of cereal aphids were found on volunteer small-grains and among weedy grass species such as rough barnyard grass, yellow foxtail, and green foxtail. Cereal aphids were not found on other weedy grasses or on noncultivated grasses. The results suggest that corn and, to less degree, sorghum served as predominant grass hosts of cereal aphids during August in South Dakota. Recent trends of expanding corn acreage in South Dakota may potentially lead to concomitant increases of cereal aphids and intensify the risk of fall infestation of winter grains by cereal aphids

Low cost ground receiving systems for television signals from high-powered communications satellites. Volume 2: Parts list and engineering drawings

Parts lists for the 2.25 GHz indoor- and antenna-unit assemblies are followed by drawings that constitute the drafting package for three converter types and the tunnel diode amplifier

Low cost ground receiving systems for television signals from high powered communications satellites, volume 1

The fabrication and evaluation of 10 engineering prototype ground signal processing systems of three converter types are reported for use with satellite television. Target cost converters and cost sensitivity analysis are discussed along with the converter configurations

Varactor diodes for millimeter and submillimeter wavelengths

Whisker-contacted GaAs Schottky barrier varactor diodes are the most common high-frequency multiplier element in use today. They are inherently simple devices that have very high frequency response and have been used to supply local oscillator power for Schottky heterodyne receivers to frequencies approaching 700 GHz. This paper discusses the development of improved varactor diode technology for space based applications at millimeter and submillimeter wavelengths

First records of \u3ci\u3eHippodamia variegata\u3c/i\u3e (Goeze) (Coleoptera: Coccinellidae) for Iowa, U.S.A.

Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae), a Palearctic lady beetle that has become established in North America, is reported for the first time from the state of Iowa, U.S.A. The earliest specimen of H. variegata from Iowa was collected in 2009, with two subsequent specimens in 2012. Collection records of an advancing, non-native species like H. variegata are important for determining comparative rates of geographic spread across various regions and understanding its invasion dynamics

Strategic gaze: an interactive eye-tracking study

We present an interactive eye-tracking study that explores the strategic use of gaze. We analyze gaze behavior in an experiment with four simple games. The game can either be a competitive (hide & seek) game in which players want to be unpredictable, or a game of common interest in which players want to be predictable. Gaze is transmitted either in real time to another subject, or it is not transmitted and therefore non-strategic. We find that subjects are able to interpret non-strategic gaze, obtaining substantially higher payoffs than subjects who do not see gaze. If gaze is transmitted in real time, gaze becomes more informative in the common interest games and players predominantly succeed to coordinate on efficient outcomes. In contrast, gaze becomes less informative in the competitive game

Photointerpretation of Skylab photography

The author has identified the following significant results. In terms of film grain texture and object definition, the S190B color positive film is distinctly superior to the S190A films, when both are compared in the 9 x 9 inch format. Within the six S190A films, the panchromatic black and white films are superior to the infrared black and white, and the color positive film is superior to the color infrared. Minimum relief differences on the order of 500 to 100 feet could be detected by stereoscopic study, however, it is not possible to determine to what extent vegetation and cultural practices assist in such delineations. Water and wind gaps through major ridges were easily seen. Streams of third order and larger were clearly visible and easy to trace; second order streams were not identified with consistency. Differences in color, tone, and textural patterns rarely supplied clues for differentiating soils or bedrock. The separation of naturally forested areas from areas of cultivation and pasture was effective and a valuable clue to the underlying geology. Suburban and industrial developments were clearly differentiated from urban areas and surrounding agricultural fields. Soil associations could be identified on a regional basis, but no sharp boundary could be drawn separating soil associations

A new state record of \u3ci\u3eEucera (Xenoglossa) kansensis\u3c/i\u3e (Hymenoptera: Apidae) in South Dakota, USA

Eucera (Xenoglossa) kansensis (Cockerell, 1905) (Hymenoptera: Apidae) is newly recorded for the state of South Dakota, USA. The bees were sampled predominantly with blue vane traps, and E. kansensis was associated with a wide range of habitats that did not include its primary floral resources of Cucurbita L. and Ipomoea L. Further study is warranted to determine the basis for the association of E. kansensis within the wide range of habitats in this study. The longhorn bee tribe Eucerini (Hymenoptera: Apidae) is a widespread and diverse group of solitary bees that includes important pollinators of both wild and agricultural plants (Dorchin et al. 2018). Based on revised phylo­genetic analyses, several members of the tribe were recently reduced to subgeneric rank within the genus Eucera (Dorchin et al. 2018). One of the groups subsumed into Eucera was the large squash bees of the genus Xenoglossa, now treated as a subgenus, which consists of oligoleges that collect pollen from the flowers of Cucurbita L. and Ipomoea L. (Hurd et al. 1971; Fowler 2020). Eucera (Xenoglossa) is morphologically distinct from congenerics by having a small tooth on the inner basal margin of each mandible (Hurd and Linsley 1964; Ascher and Pickering 2022). Eucera (Xenoglossa) consist of seven species distributed from Central America to the northern regions of the United States of America (USA) (Michener 2007). Two species, E. strenua (Cresson, 1878) and E. kansensis (Linnaeus, 1763), are distributed throughout much of the USA (Ascher and Pickering 2022). In this paper, we add a state new record for South Dakota to the known geographic distribution of E. kansensis (Fig. 1) within the country.

Design and Characterization of 1.8-3.2 THz Schottky-based Harmonic Mixers

A room-temperature Schottky diode-based WM-86 (WR-0.34) harmonic mixer was developed to build high-resolution spectrometers, and multi-pixel receivers in the THz region for applications such as radio astronomy, plasma diagnostics, and remote sensing. The mixer consists of a quartz-based Local Oscillator (LO), Intermediate-Frequency (IF) circuits, and a GaAs-based beam-lead THz circuit with an integrated diode. Measurements of the harmonic mixer were performed using a 2 THz solid-state source and 2.6906 THz QCL. A conversion loss of 27 dB for the 3rd harmonic mixing and a conversion loss of 30 dB for the 4th harmonic mixing was achieved. This is the first development of a wideband WM-86 (WR-0.34) harmonic mixer with planar Schottky diode integrated on a beam-lead THz circuit that uses a lower LO harmonic factor for 1.8-3.2 THz RF frequency. Furthermore, this result represents the best Schottky-based mixer in this frequency range

Comparison of a Synthetic Chemical Lure and Standard Fermented Baits for Trapping Drosophila suzukii (Diptera: Drosophilidae)

We determined the attractiveness of a new chemical lure compared with fermented food baits in use for trapping Drosophila suzukii Matsumura, spotted wing drosophila (Diptera: Drosophilidae), in Connecticut, New York, and Washington in the United States and at Dossenheim in Germany. The chemical lure (SWD lure) and food baits were compared in two types of traps: the dome trap and a cup trap. Regardless of trap type, numbers of male and female D. suzukii trapped were greater with the SWD lure compared with apple cider vinegar (ACV) baits at the Washington and New York sites, and were comparable with numbers of D. suzukii captured with a wine plus vinegar bait (W + V) at Germany site and a combination bait meant to mimic W + V at the Connecticut site. Averaged over both types of attractants, the numbers of D. suzukii captured were greater in dome traps than in cup traps in New York and Connecticut for both male and female D. suzukii and in Washington for male D. suzukii. No such differences were found between trap types at the Washington site for female and Germany for male and female D. suzukii. Assessments were also made of the number of large (>0.5 cm) and small (<0.5 cm) nontarget flies trapped. The SWD lure captured fewer nontarget small flies and more large flies compared with ACV bait in New York and fewer nontarget small flies compared with W + V in Germany, although no such differences were found in Washington for the SWD lure versus ACV bait and in Connecticut for the SWD lure versus the combination bait, indicating that these effects are likely influenced by the local nontarget insect community active at the time of trapping. In New York, Connecticut, and Germany, dome traps caught more nontarget flies compared with cup traps. Our results suggest that the four-component SWD chemical lure is an effective attractant for D. suzukii and could be used in place of fermented food-type bait