Multivariate analysis of invasive plant species distributions in southern US forests

Landscape Ecology - Invasive plants cause significant impacts in forested areas throughout the world. However, little is known about the relative importance of environmental drivers on the...     

Spatiotemporal Distribution of Two Euschistus spp. Stink Bugs (Hemiptera: Pentatomidae) in Southeastern Farmscapes

Stink bugs (Hemiptera: Pentatomidae) are ubiquitous, cryptic, phytophagous pests that are found in many crops. In agroecosystems, individuals disperse from adjacent noncrop hosts and tend to aggregate or cluster within fields. In this study, we characterized the distribution of Euschistus servus (Say) and Euschistus tristigmus (Say) (Hemiptera: Pentatomidae) over 2 yr at three southeastern United States farmscapes. Stink bugs were captured in pheromone-baited traps, and Spatial Analysis by Distance Indices (SADIE) used to identify the location of significant aggregations by habitat type and season. Euschistus servus adults were more likely to be captured in pecan orchards, cotton, other crops, or unmanaged habitats than in woodland habitats. Significant aggregations of E. servus were detected in a variety of habitats including pecan, corn, cotton, peanut, and tobacco, as well as fallow and hay fields, pastures, and hedgerows. Fewer adult E. tristigmus were captured than E. servus adults, and E. tristigmus adults were typically trapped and aggregated in woodland habitats. The resulting data provide an important understanding regarding the seasonal movement and relative abundance levels of stink bug populations, which are critical to the development of integrated pest management strategies.     

Isoflucypram,the first representative of a new succinate dehydrogenase inhibitor fungicide subclass: Its chemical discovery and unusual binding mode

Succinate dehydrogenase inhibitors (SDHIs) have played a crucial role in disease control to protect cereals as well as fruit and vegetables for more than a decade. Isoflucypram, the first representative of a newly installed subclass of SDHIs inside the Fungicide Resistance Action Committee (FRAC) family of complex II inhibitors, offers unparalleled long‐lasting efficacy against major foliar diseases in cereals. Herein we report the chemical optimization from early discovery towards isoflucypram and the first hypothesis of its altered binding mode in the ubiquinone binding site of succinate dehydrogenase. © 2020 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

INTEGRATED CROP-LIVESTOCK SYSTEMS: LESSONS FROM NEW YORK,BRITISH COLUMBIA,AND THE SOUTH-EASTERN UNITED STATES

• Livestock production in North America has moved to fewer farms with greater inventories • Land application of livestock manures is a preferred nutrient recycling strategy • Confined animal feeding operations have challenges to utilize livestock manure sustainably • Integration of livestock and cropping systems is possible on a farm or among farms • Nutrient balance is needed for environmental sustainability Livestock production in the United States (US) and Canada is diverse, but shows a common trend in most livestock sectors toward fewer farms producing the majority of animal products despite a large number of farms still small in production scale. The migration to larger and more concentrated animal feeding operations in beef finishing and poultry, swine, and dairy production allows processors to streamline supplies to meet market demand for abundant, low-cost livestock products, whether that be for packaged meat, dairy products, or eggs. With concentration of livestock operations comes the challenge of managing manures. When sufficient land is available and nutrients are needed, livestock manure is an excellent nutrient source and land application is the preferred method of recycling this resource. However, when livestock production is constrained in a geographical area and animal densities are high, manure may become an environmental liability with potentially greater risk for runoff and leaching of nutrients, emission of odors, ammonia, and greenhouse gases, and release to the environment of pathogens and chemicals of emerging concern. Addressing these challenges now and into the future requires learning from mistakes and adopting successful approaches. We describe different levels of integration between livestock and crop producers in New York, British Columbia, and the south-eastern US as learning opportunities to improve economic and environmental sustainability. Examples show that effective solutions should recognize (1) manure has value and is not just a cost, (2) farmers, farm advisors, extension educators, nutrient management planners, crop advisors, nutritionists, state agency personnel, regulators, and university researchers need to be active participants in development of solutions, and (3) change to a sustainable future requires a combination of government regulation and outcome-based incentives.     

The performance and design of packed column aeration systems for aquaculture

The packed column aerator (PCA) is a highly efficient aerator that can be used for oxygen and nitrogen + argon removal. Standard transfer efficiencies (N₀) for oxygen range from 1·5 to 2·0 kg O₂/kWh. If 1–2 m of hydraulic head is available, N₀ can be as high as 80 kg O₂/kWh. A mass transfer model was developed for design purposes. Recommended design parameters and procedures are presented for full-scale PCA.     

Carbonate mineral filtrants with new surfaces reduce alkalinity in seawater and artificial seawater: Preliminary findings

Silica sand (silica), coral (aragonite), and oyster shell (calcite) were ground to similar particle sizes and placed in seawater and artificial seawater (GP2 Medium). Alkalinity and pH values of the artificial seawater decreased substantially over 24 h when in contact with coral and oyster shell; the effects in seawater were minor. Once alkalinity has been reduced, the maintenance of stable pH at values typical of seawater is made more difficult. The data, which are preliminary, have practical application.     

QTL for IHNV resistance and growth identified in a rainbow (Oncorhynchus mykiss) × Yellowstone cutthroat (Oncorhynchus clarki bouvieri) trout cross

Infectious hematopoietic necrosis virus (IHNV) is a major constraint to rainbow trout culture. Yellowstone cutthroat trout (Oncorhynchus clarki bouvieri) have greater resistance to this virus than do rainbow trout (O. mykiss), but the genetic mechanism of this resistance is not understood. We conducted a genome scan using a backcross of cutthroat trout into a rainbow trout background to estimate the number and locations of quantitative trait loci (QTL) associated with IHNV resistance and growth in trout. IHNV resistance was considered in terms of both survival (binary trait) and days to death (quantitative trait). The genetic map was scanned using interval mapping via two different approaches: one model considered survival alone and a second two-part model combined both survival and days to death. Three QTL were significantly (P ≤ 0.05) associated with virus resistance genome-wide, explaining 32.5% of the phenotypic variation. Cutthroat alleles at two of these QTL resulted in increased resistance to the pathogen, as expected. No growth QTL were detected in this cross. We suggest that these traits are genetically independent.     

Microbial Ecology of the Gastrointestinal Tract of Fish and the Potential Application of Prebiotics and Probiotics in Finfish Aquaculture

Aquaculture is one of the fastest growing industries in the world. The need for enhanced disease resistance, feed efficiency, and growth performance of cultured organisms is substantial for various sectors of this industry. If growth performance and feed efficiency are increased in commercial aquaculture, then the costs of production are likely to be reduced. Also if more fish are able to resist disease and survive until they are of marketable size, the subsequent cost of medication and overall production costs would be reduced drastically. It has been documented in a number of food animals that gastrointestinal microbiota play important roles in affecting the nutrition and health of the host organism. Thus, various means of altering the intestinal microbiota to achieve favorable effects such as enhancing growth, digestion, immunity, and disease resistance of the host organism have been investigated in various terrestrial livestock as well as in humans. Dietary supplementation of prebiotcs, which are classified as non‐digestible food ingredients that beneficially affect the host by stimulating growth and/or activity of a limited number of health‐promoting bacteria such as Lactobacillus and Bifidobacter spp. in the intestine, while limiting potentially pathogenic bacteria such as Salmonella, Listeria and Escherichia coli, have been reported to favorably affect various terrestrial species; however, such information is extremely limited to date for aquatic organisms. Effects of probiotics, defined as live microbial feed supplements, on gastrointestinal microbiota have been studied in some fishes, but the primary application of microbial manipulations in aquaculture has been to alter the composition of the aquatic medium. In general, the gastrointestinal microbiota of fishes including those produced in aquaculture has been poorly characterized, especially the anaerobic microbiota. Therefore, more detailed studies of the microbial community of cultured fish are needed to potentially enhance the effectiveness of prebiotic and probiotic supplementation. This review summarizes and evaluates current knowledge of intestinal microbial ecology of fishes, the various functions of this intestinal microbial community, and the potential for further application of prebiotics and probiotics in aquaculture.     

Chloropicrin Soil Fumigation Reduces <Emphasis Type="Italic">Spongospora subterranea</Emphasis> Soil Inoculum Levels but Does Not Control Powdery Scab Disease on Roots and Tubers of Potato

The effect of chloropicrin fumigation on the soil populations of Spongospora subterranea and the development of powdery scab, formation of root galls and tuber yield was investigated in seven field trials conducted in Minnesota and North Dakota. Sixteen potato cultivars, with different levels of susceptibility to disease on roots and tubers, were planted in plots treated with chloropicrin at rates ranging from zero to 201.8 kg a.i. ha^?1. The amount of S. subterranea DNA in soil was determined using qPCR. Bioassays were conducted to further assess the effect of chloropicrin fumigation on root colonization by S. subterranea in two potato cultivars with contrasting disease susceptibility. In the field, chloropicrin applied at rates between 70.1 to 201.8 kg a.i. ha^?1 significantly decreased S. subterranea initial inoculum in soil but increased the amount of disease observed on roots and tubers of susceptible cultivars. The effect of increasing disease was confirmed in controlled conditions experiments. Although the amount of S. subterranea DNA in roots of bioassay plants increased with increasing chloropicrin rates, it remained similar among potato cultivars. Chloropicrin fumigation significantly increased tuber yield which in cultivars such as Shepody and Umatilla Russet were associated with the amount root galls (r = 0.30; P < 0.03). Results of these studies contradict earlier reports on the use of chloropicrin fumigation for the control of powdery scab. Factors other than inoculum level, such as environmental conditions that affect inoculum efficiency and host susceptibility, may be significant contributors to the development of powdery scab and root gall formation.