Biology and Management of Billbugs (Coleoptera: Curculionidae) in Turfgrass

Billbugs (Coleoptera: Curculionidae: Sphenophorus spp.) are a complex of weevil pests affecting turfgrass throughout the United States. Billbug larvae cause damage by feeding in stems, on roots, and on the crowns of turf, causing severe discoloration and eventual plant death. Monitoring efforts have focused on nondestructive pitfall sampling of ground-active billbug adults and on destructive sampling using soil cores for larval stages in the soil. Given the cryptic nature of the susceptible larval stages, billbugs are typically managed by preventive applications of long-residual, systemic insecticides, including neonicotinoids and anthranilic diamides. Despite knowledge of effective management practices including pest-resistant turf varieties, irrigation management, and microbial controls that contribute to an IPM approach, billbug management continues to rely heavily on prophylactic synthetic insecticides. This review will summarize the identification and biology of billbugs and strategies for their management

Report on Laboratory Testing of Fastening of CFS Track to Concrete Base Materials with PAFs, with Revision

The 2012 AISI S100 Section E5 includes design provisions for power-actuated fasteners (PAFs) for connection of cold-formed steel (CFS) to steel base materials. However, a need exists to develop an in-depth understanding when CFS wall tracks are attached to concrete base materials as part of interior and exterior wall framing applications. Current code requirements, as specified by ASCE 7 – 2010 Chapter 13 (Exception to Section 13.4.5), limit individual PAFs in nonstructural component connections as part of distributed systems, to a sustained tension service load of 90 lbs in concrete and 250 lbs in steel in Seismic Design Categories D, E, and F. Although the use of PAFs is very common in CFS wall framing applications, there is a need for an in-depth system study examining the cyclic / seismic lateral performance using this connection method. This experimental test program demonstrates that tested capacities of the CFS track-to-concrete PAF connections exceed those used for design, under the current ASCE 7 (2010) provisions. Experimental data further demonstrates that ductile steel failure modes limit the capacity of the connection with 33 mil and thinner CFS track. Where this failure mode is dominant, the use of AISI S100-12 Section E5.3.2 to determine the capacity of the CFS track connection is appropriate and further limiting the capacity to current standards is not warranted. Where this failure mode is not dominant, and PAF failure modes control the system behavior, the capacity of the CFS track connections should be more accurately descripted in AISI S100-12 Section E5 and the International Building Code (ICC, 2012)

Stem Nematode Counteracts Plant Resistance of Aphids in Alfalfa, Medicago Sativa

Plants are exploited by a diverse community of insect herbivores and phytopathogens that interact indirectly through plant-mediated interactions. Generally, plants are thought to respond to insects and pathogens through different defensive signaling pathways. As plants are selected for resistance to one phytophagous organism type (insect vs. pathogen) in managed systems, it is not clear how this selection may affect community interactions. This study examined the effect of nematode-resistant varieties on aphid (Acyrthosiphon pisum) suppression, and then determined how infection by the stem nematode, Ditylenchus dipsaci, mediated ecological effects on aphids and on plant defense proteins. Four alfalfa (Medicago sativa) varieties were selected with resistance to nematodes only (+,−), aphids only (−,+), nematodes and aphids (+,+), and susceptibility to nematodes and aphids (−,−). Field and greenhouse experiments were conducted to isolate the effect of nematode infection and aphid abundance on each variety. We found that varieties resistant to nematode, regardless of aphid resistance, had the lowest aphid counts, suggesting possible cross-resistance. Aphid abundance, however, increased when plants were exposed to nematodes. Resistant varieties were associated with elevated saponins but these compounds were not affected by insect or pathogen feeding. Concentrations of peroxidases and trypsin inhibitors, however, were increased in nematode resistant varieties when exposed to nematodes and aphids, respectively. The patterns of plant defense were variable, and a combination of resistance traits and changes in nutrient availability may drive positive interactions between nematodes and aphids aboveground

Planting date effects on the germinability and seedling vigour of Abutilon theophrasti (Malvaceae) seeds

Abutilon theophrasti (Malvaceae) is a troublesome annual weed in many maize and soybean cropping systems of Canada and the United States. Seeds of A. theophrasti exhibit physical dormancy. Differences in the growing environment of parent plants may influence the germinability of seeds and vigour of seedlings produced by this species because of variation in resource allocation to seed development. Thus, the germinability of seeds and subsequent seedling vigour were examined for A. theophrasti plants grown in monoculture at a density of 4.2 plants m-2 under varying natural photoperiods in central New York State. Treatments were established by transplanting A. theophrasti seedlings on three dates: 15 May, 4 June, and 30 June 2000, which correspond to peak photoperiods of 15, 14, and 13 hours, respectively. Seeds produced under the shorter photoperiod (13 h) weighed, on average, 1.5 mg less than seeds produced under the longer photoperiod (15 h). Contrary to expectations, seeds of A. theophrasti that matured under shorter photoperiods had lower germinability (80%) than seeds produced under longer photoperiods (98%). Early radicle growth, a measure of seedling vigour, did not differ between the photoperiod treatments. Environmental conditions other than photoperiod (i.e. water availability) prevailing during the 2000-growing season may have influenced seed coat thickness and consequently affected the germinability of seeds.L’Abutilon theophrasti (Malvaceae) est une mauvaise herbe annuelle qui gêne la production du maïs et du soja dans plusieurs systèmes de culture du Canada et des États-Unis. Les graines de l’A. theophrasti possèdent une dormance physique. Des différences de l’environnement dans lequel croissent les plantes mères peuvent influencer la germination des graines et la vitalité des plantules de cette espèce à cause de variations dans l’affectation des ressources avant que les graines soient pleinement développées. Ainsi, la germination des graines et la vitalité des plantules qui en sont issues ont été étudiées pour l’A. theophrasti en monoculture à une densité de 4,2 plantes m-2 sous diverses photopériodes naturelles du centre de l’État de New York. Les traitements ont débuté par la plantation de plantules de l’A. theophrasti à trois dates, 15 mai, 6 juin et 30 juin 2000, qui correspondent respectivement à des photopériodes maximales de 15, 14 et 13 heures. Les graines produites avec la photopériode la plus courte (13 h) pesaient en moyenne 1,5 mg de moins que les graines produites avec les plus longues photopériodes (15 h). Contrairement à ce qui était prévu, les graines de l’A. theophrasti qui se sont formées lors des photopériodes les plus courtes avaient une germination plus faible (80 %) que les graines formées lors des photopériodes les plus longues (98 %). La croissance précoce de la radicule, une mesure de la vitalité des plantules, est restée la même pour les différentes photopériodes. Les conditions environnementales autres que la photopériode (c.-à-d. la disponibilité en eau) qui régnaient au cours de la saison de croissance de 2000 peuvent avoir influencé l’épaisseur du tégument et avoir ainsi eu un effet sur la germination des graines

Combinations of Plant Water-Stress and Neonicotinoids Can Lead to Secondary Outbreaks of Banks Grass Mite (Oligonychus Pratensis Banks)

Spider mites, a cosmopolitan pest of agricultural and landscape plants, thrive under hot and dry conditions, which could become more frequent and extreme due to climate change. Recent work has shown that neonicotinoids, a widely used class of systemic insecticides that have come under scrutiny for non-target effects, can elevate spider mite populations. Both water-stress and neonicotinoids independently alter plant resistance against herbivores. Yet, the interaction between these two factors on spider mites is unclear, particularly for Banks grass mite (Oligonychus pratensis; BGM). We conducted a field study to examine the effects of water-stress (optimal irrigation = 100% estimated evapotranspiration (ET) replacement, water stress = 25% of the water provided to optimally irrigated plants) and neonicotinoid seed treatments (control, clothianidin, thiamethoxam) on resident mite populations in corn (Zea mays, hybrid KSC7112). Our field study was followed by a manipulative field cage study and a parallel greenhouse study, where we tested the effects of water-stress and neonicotinoids on BGM and plant responses. We found that water-stress and clothianidin consistently increased BGM densities, while thiamethoxam-treated plants only had this effect when plants were mature. Water-stress and BGM herbivory had a greater effect on plant defenses than neonicotinoids alone, and the combination of BGM herbivory with the two abiotic factors increased the concentration of total soluble proteins. These results suggest that spider mite outbreaks by combinations of changes in plant defenses and protein concentration are triggered by water-stress and neonicotinoids, but the severity of the infestations varies depending on the insecticide active ingredient

Generalist and Specialist Mite Herbivores Induce Similar Defense Responses in Maize and Barley but Differ in Susceptibility to Benzoxazinoids

While substantial progress has been made in understanding defense responses of cereals to insect herbivores, comparatively little is known about responses to feeding by spider mites. Nevertheless, several spider mite species, including the generalist Tetranychus urticae and the grass specialist Oligonychus pratensis, cause damage on cereals such as maize and wheat, especially during drought stress. To understand defense responses of cereals to spider mites, we characterized the transcriptomic responses of maize and barley to herbivory by both mite species, and included a wounding control against which modulation of defenses could be tested. T. urticae and O. pratensis induced highly correlated changes in gene expression on both maize and barley. Within 2 h, hundreds of genes were upregulated, and thousands of genes were up- or downregulated after 24 h. In general, expression changes were similar to those induced by wounding, including for genes associated with jasmonic acid biosynthesis and signaling. Many genes encoding proteins involved in direct defenses, or those required for herbivore-induced plant volatiles, were strongly upregulated in response to mite herbivory. Further, biosynthesis genes for benzoxazinoids, which are specialized compounds of Poaceae with known roles in deterring insect herbivores, were induced in maize. Compared to chewing insects, spider mites are cell content feeders and cause grossly different patterns of tissue damage. Nonetheless, the gene expression responses of maize to both mite herbivores, including for phytohormone signaling pathways and for the synthesis of the benzoxazinoid 2-hydroxy-4,7-dimethoxy-1,4-benzoxazin-3-one glucoside, a known defensive metabolite against caterpillars, resembled those reported for a generalist chewing insect, Spodoptera exigua. On maize plants harboring mutations in several benzoxazinoid biosynthesis genes, T. urticae performance dramatically increased compared to wild-type plants. In contrast, no difference in performance was observed between mutant and wild-type plants for the specialist O. pratensis. Collectively, our data provide little evidence that maize and barley defense responses differentiate herbivory between T. urticae and O. pratensis. Further, our work suggests that the likely route to specialization for O. pratensis involved the evolution of a robust mechanism to cope with the benzoxazinoid defenses of its cereal hosts

Low-cost syngas shifting for remote gasifiers: Combination of CO2 adsorption and catalyst addition in a novel and simplified packed structure

This paper presents the technical validation of a novel, low-complexity alternative based on the inclusion of a patented (IEPI-MU-2016-185) packed bed for improving the performance of remote, small-scale gasification facilities. This study was carried out in an updraft, atmospheric-pressure gasifier, outfitted with a syngas reflux line, air and oxygen feed, and an upper packed-bed coupled to the gasification unit to improve the syngas quality by catalytic treatment and CO2 adsorption. The experimental facility is located in the rural community San Pedro del Laurel, Ecuador. Gasification experiments, with and without packed material in the upper chamber, were performed to assess its effect on the syngas quality. The assessment revealed that the packed material increases the carbon monoxide (CO) content in the syngas outlet stream while carbon dioxide (CO2) was reduced. This option appears to be a suitable and low-complexity alternative for enhancing the content of energy vectors of syngas in gasification at atmospheric pressure since CO/CO2 ratios of 5.18 and 3.27 were achieved against reported values of 2.46 and 0.94 for operations which did not include the addition of packed material. It is concluded that the upper packed-bed is an active element able to modify syngas characteristics since CO2 content was reduce