<p> Field corn, <i>Zea mays</i> L., has been introduced to the market with pyramided <i>Bacillus thuringiensis</i> (Bt) corn technologies. These technologies reduce kernel damage from ear feeding caterpillar pests, including corn earworm, <i>Helicoverpa zea</i> (Boddie). The first generation Bt traits in field corn demonstrated limited activity on corn earworm feeding on grain in ears. The pyramided corn technologies have greater cumulative protein concentrations and improved expression throughout the plant, so these corn traits should provide an effective management tool against these pests. In addition, reduced kernel injury may also have a direct effect on physical grain quality. The results for this trial showed no relationship between number of damaged kernels and yield was observed for corn hybrid expressing the Herculex^&reg;, YieldGard^&reg;, or Genuity VT Triple Pro^&reg; technologies. A significant relationship between both damaged kernels and test weight and damaged kernels and aflatoxin concentrations was observed in two technologies.</p>

<p> The objectives of this research were to evaluate management options for tobacco thrips, <i>Frankliniella fusca</i> (Hinds), and reniform nematode, <i>Rotylenchulus reniformis</i> (Linford &amp; Oliverira), in cotton productions systems. When evaluating tillage practices for pest control, conservational tillage reduced thrips densities and damage, while the impact on nematode densities is less understood and in this study had no impact. Insecticide seed treatments remain a vital resource for controlling thrips in Mid-South cotton production systems. When incorporating an early season herbicide application for weed control, systems with an insecticide seed treatment generally tolerated herbicide injury better than those with early season stress from thrips and nematodes. When using foliar applications as an alternative option for thrips management, early season automatic applications at the cotyledon stage followed by one or two sequential applications provided similar efficacy to the insecticide seed treatment. For reniform nematode management, 1, 3-dichloropropene reduced densities lower than that of the untreated control or aldicarb; however, depending on environmental conditions this practice may not result in yield increases great enough to warrant the cost of application. These data highlight the importance of effective control of thrips whether it be via at-planting or foliar applications. 1, 3-dichloropropene reduced nematode densities and is an effective option in nematode management; however, nematodes are a stress pathogen and the ability to minimize other seasonal stresses ,such as water stress, will determine if a nematicide application may be needed. While environmental conditions may be optimal to allow for plant recoverability, effective early season pest management decreases the potential for delayed crop maturity which could lead to increased input cost or reduced yield later in the season.</p><p>

<p> Soybean, <i>Glycine max</i> (L.) Merr., is planted across a vast amount of land in the Mid-Southern U.S. (Arkansas, Louisiana, Mississippi, and Tennessee), and yield responses to defoliation can vary. Experiments were conducted during 2015-2017 evaluating how soybean yield responds to multiple and continuous defoliation, as well as planting date and plant population. Multiple defoliation events were evaluated by defoliating soybean at varying levels at V3, V6, and both growth stages. There was no interaction between defoliation occurring at V3 and V6 growth stages, indicating that the impact of each defoliation event was independent of the other. The effect of continuous defoliation was evaluated by defoliating soybean weekly, beginning at V2. Defoliation continued throughout the vegetative growth stages or throughout the entire growing season, and was compared to the same defoliation level occurring one time at R3. Continuous defoliation during vegetative growth stages only, did not reduce yield at any of the levels tested. Defoliation occurring throughout the growing season reduced yields more than a one-time defoliation event at R3, but only when defoliation levels exceeded the 20% defoliation threshold. This indicates that thresholds do not need to be modified to account for multiple or continuous defoliation. To evaluate the effect of planting date on yield loss from defoliation, soybean was planted at six planting dates beginning in early-April and continuing through mid-June. Each planting date included a defoliated treatment and an undefoliated control. It was determined that later planted soybean lose a greater amount of yield than earlier planted. Higher yielding soybean also lost more yield than lower yielding soybean at every planting date until Mid-June. It was concluded that late planted soybeans could benefit from a lower treatment threshold. The effect of plant population on yield loss from defoliation was evaluated by planting soybean at five populations ranging from 123,500 seeds/ha to 420,070 seeds/ha. A undefoliated control and a defoliated treatment was included for each plant population. Defoliation significantly reduced yields only where final plant populations were lower than 192,800 plants/ha. This indicates that fields with substandard plant populations are more susceptible to yield loss from defoliating pests.</p><p>

<p> Research was conducted 2014-2016 to determine how tobacco thrips (<i> Frankliniella fusca</i>) (Hinds) resistance to neonicotinoid insecticides impact thrips resistance to neonicotinoid insecticides in cotton, <i> Gossypium hirsutum</i> (L.).Studies included bioassays to determine severity and mechanism of resistance and evaluation of host plant characteristics in multiple cotton varieties. Another aspect of research focused on the neonicotinoid insecticide clothianidin and its leaching ability as a seed treatment on corn by evaluating soil type, water regime, and amount found in tissue.</p><p>

<p> Experiments were conducted to determine the impact of combining multiple best management practices to manage the tarnished plant bug, Lygus lineolaris (Palisot de Beauvois), on cotton. The implementation of this program reduced the amount of insecticide applications needed, significantly increased both square retention during the three weeks of squaring, and yield in the Delta region. Another study was conducted to explore behavioral responses of tarnished plant bug nymphs to several classes of insecticides. There appeared to be both avoidance and attraction depending on insecticide class. The presence of an insecticide did not affect the fruiting structure tarnished plant bugs were found on in the field, there were significantly more tarnished plant bugs found in the middle of the plant than the top or bottom at 3 DAT. At 7 DAT there were significantly more tarnished plant bugs found on the top of the plant followed by the middle then bottom.</p>

The apple maggot fly, Rhagoletis pomonella (Walsh), is a key pest attacking apple fruit in eastern and midwestern North America. Sticky-coated 8-cm spheres baited with fruit odor (butyl hexanoate) have been the mainstay of a behavioral approach to direct maggot fly control. Improvements upon the red sphere trapping system are needed, however, if it is to be feasible and cost-effective for widespread commercial use. Several aspects of visual and odor stimuli influencing apple maggot fly captures on sticky red spheres were investigated. Results indicated that the efficacy of spheres in capturing adults was not improved by increasing sphere size to a diameter greater than that of 8-cm or by using more synthetic fruit odor (butyl hexanoate). Significant improvement was attained by using synthetic food odor (ammonium carbonate) together with butyl hexanoate. Distance (15-60 cm) of a butyl hexanoate source from a red sphere had no significant effect on fly captures. Semi-natural (field cage) conditions were used to examine response patterns of females to red spheres in relation to fly age and prior ovipositional experience. As fly age increased from a reproductively immature stage to a mature stage, the probability of a fly finding a sphere hung in a host tree increased. Simultaneously, the likelihood that a fly would deposit eggs in host fruit before encountering a sphere increased. Prior experience with different species or cultivars of host fruit did not have significant effect on the ability of flies to find red spheres but reduced the likelihood of oviposition in unfamiliar fruit. Prior experience with the same species or cultivar of host fruit had no apparent effect on fly ability to find a red sphere trap or to oviposit in familiar fruit. Various feeding stimulants, pesticides, and residue-extending agents were evaluated in laboratory and field cage experiments for suitability in developing a nonsticky lethal sphere. Spheres treated with a mixture containing 1.05% (a.i.) dimethoate (insecticide), 58.95% corn syrup (feeding stimulant) and 40% latex paint (residue extending agent) and not exposed to weather killed a great majority of alighting flies. However, these spheres became ineffective after exposure to weather (rainfall). Retreating weather-exposed spheres with feeding stimulant restored effectiveness. Studies conducted in commercial orchards showed that pesticide-treated spheres, like the sticky spheres, had much potential for eliminating insecticide sprays against the flies. Current necessity of retreating pesticide-treated spheres with feeding stimulant after each rainfall compromises present utility for commercial use. Development of a polymer to protect residual effectiveness of feeding stimulant is key to further widespread commercial use of this simpler behavioral approach to controlling apple maggot flies.

<p> Various models of density dependence predicted different evolutionary outcomes for <i>Helicoverpa zea, Diabrotica virgifera,</i> and <i> Ostrinia nubilalis</i> using simple and complex resistance evolution models, different dose assumptions and refuge proportions. Increasing available refuge increased durabilities of pyramided Plant-Incorporated-Protectants (PIPs), especially between 1&ndash;5%. For some models of density dependence and pests, additional refuge resulted in faster adaptation rates. Significant considerations should be given to a pest's intra-specific competition in simple and complex theoretical models when designing insect resistance management plans. </p><p> Life-history, refuge, and dose characteristics of a PIP had different effects on the adaptation rate of a generic pest of Bt, and unexpected outcomes occurred. Intrinsic growth rate 'R₀' was the strongest evolutionary force, and large R₀'s reduced time to resistance for a high dose PIP to similar levels as projected for a low dose PIP. This was caused by differential density dependent effects in refuge and Bt fields that elevated generational resistance increases beyond those from selection alone. Interactions between density dependence and R₀ were always present and further affected the life-time of the PIPs. Varying 'average dispersal distance' did not affect evolutionary outcomes; however, increasing the proportion of the population engaging in dispersal often increased the durability of high dose PIPs. When resistance genes spread from a hypothetical hotspot, local resistance phenomena developed in the immediate surroundings. Higher growth rates lead resistance to spread faster through the landscape than lower rates. Increasing available refuges slowed adaptation rates to single PIPs and low dose pyramids, although non-linear trends were possible. </p><p> Integrated Pest Management (IPM) practices at the onset of PIP commercialization slowed pest adaptation rates. For corn rootworm, interspersing non-selective periods with IPM+IRM delayed resistance evolution, yet crop rotation was the best strategy to delay resistance. For bollworm inclusion of isoline corn as an IPM tool did not increase the life-time of the PIP. A local resistance phenomenon for rootworm was maintained immediately surrounding the hotspot; random selection of mitigatory strategies in the landscape slowed adaptation rates while mitigation in the hotspot alone did not. Mitigation extended the life-time of the pyramid minimally for both corn rootworm and bollworm.</p>

<p> Alkali bees, <i>Nomia melanderi</i>, are native, solitary, soil&ndash;nesting bees commercially managed in southeastern Washington State. They nest in dense aggregations and are important pollinators of alfalfa produced for seed. The Washington State Department of Transportation (WSDOT) proposed safety improvements to US Highway 12 through the Touchet&ndash; Lowden&ndash;Gardena alfalfa seed growing district, an area critical to alfalfa seed production. This includes northern realignment to accommodate a wider roadway and avoid impacting any towns. Relocation of the highway will bisect several <i> N. melanderi</i> nesting aggregations and alfalfa fields. The study has three objectives: 1) survey the population abundance of <i>N. melanderi </i> across the region by comparing two sampling techniques; 2) determine bee flight heights across roads; and 3) determine <i>N. melanderi</i> foraging range using transgenic pollen. </p><p> Regression was significant between the two population sampling methods. Mean emergence hole counts, mean prepupal counts, and the surface area of the nesting aggregations, were used to estimate the abundance of<i> N. melanderi</i> in each bee bed. We constructed a &ldquo;vehicular bee sweeper&rdquo; designed to capture insects at specific heights over the roadway. The majority of <i>N. melanderi</i> flew below 2.1 m when no other factors were considered, but environmental conditions like temperature and wind speed affected number and flight height of <i>N. melanderi</i>. To determine <i>N. melanderi</i> foraging distance, adults were collected from their nest sites, and pollen on their hind tibia was tested for the presence or absence of Roundup&ndash;^&reg;Ready alfalfa (RRA). The minimum foraging distance was 0.04 km and the maximum was 4.62 km. These distances suggest that <i>N. melanderi</i> will cross the highway for floral resources, increasing potential mortality. </p><p> Studying <i>N. melanderi</i> population abundance and flight characteristics allows us to understand the potential impacts of the proposed highway on bee populations and on alfalfa seed producers. The non&ndash;destructive quadrat method of sampling <i>N. melanderi</i> populations is robust compared to the destructive, labor-intensive, soil core method. Due to the low-flying nature and foraging distance of <i>N. melanderi</i>, vehicle strikes can be expected to cause mortality in bisected populations. Ultimately, recommendations will be made to highway designers to minimize and mitigate these effects. &#8195;</p>

<p> The goldspotted oak borer (GSOB), <i>Agrilus auroguttatus</i> Schaeffer, is an invasive wood-borer associated with tree mortality in San Diego County, California since 2008, and is believed to have been introduced via infested firewood from southeastern Arizona. From 2011-2013, I recorded GSOB emergence holes on <i>Quercus agrifolia</i> trees at eight locations within San Diego County. I evaluated the effectiveness of crown class and purple prism traps as tools to monitor GSOB populations. I also identified possible tree and site characteristics that could explain the variation in GSOB population densities. Crown class was useful in monitoring GSOB populations unlike purple prism traps. Larger trees (>50 cm diameter at breast height), trees located near a stand's edge, and trees previously infested had the greatest emergence hole densities. Sites closer to GSOB's putative original point of infestation and those with an intermediate <i>Q. agrifolia </i> density (30-50 trees per hectare) had greatest infestation levels. </p>

<p> Hybrid poplars are a short rotation woody crop grown for a variety of target markets including paper pulp, saw timber, and biofuels in the Pacific Northwest. Development of pest control strategies within hybrid poplar plantations over the last several decades has focused on controlling foliar feeding herbivores and wood boring pests, and has overlooked the epigeal arthropod community. Understanding this unstudied suite of organisms would allow pest managers to better evaluate the impact their management strategies have on the poplar agroecosystem. Qualitative surveys of the arthropod communities in hybrid poplar plantations and nearby native habitats demonstrated that a greater arthropod diversity persists in the surrounding native areas. Additionally, the poplar plantation's epigeal arthropod community was composed of species found within sampled native areas. </p><p> Historically poplar research focused on protecting trees in the years following establishment through harvest from emerging pests while discounting cutting mortality by replanting areas of failure. Describing unrooted cutting transplant morality and distribution within newly established planting block could provide a risk assessment tool that growers could utilize to evaluate their potential crop loss. It was determined through the examination of damaged cuttings that several pests were responsible for diminishing establishment success. Identification of these risks led to the development of a management strategy to reduce mortality in newly planted areas. Soaking cuttings in imidacloprid for 48 hrs provided superior herbivore protection for unrooted cuttings until root formation allowed for uptake from chemigation treatments. </p><p> An additional study was motivated by the increased concern in growing `clear wood' as poplar has migrated from pulp to saw timber. The accompanying renewed interest in reducing insect galleries in mature trees led to the exploration of deploying a mass trapping, or trap out, effort to reduce populations of <i> Prionoxystus robiniae</i> (Lepidoptera Cossidae) in specific areas of a hybrid poplar plantation. We show that a trap out effort of roughly 5 pheromone-baited traps/ha decimated <i>P. robiniae</i> populations in treated areas throughout the trap out effort and three years post application.</p>