Biochemical and nanotechnological approaches to combat phytoparasitic nematodes.

The foundation of most food production systems underpinning global food security is the careful management of soil resources. Embedded in the concept of soil health is the impact of diverse soil-borne pests and pathogens, and phytoparasitic nematodes represent a particular challenge. Root-knot nematodes and cyst nematodes are severe threats to agriculture, accounting for annual yield losses of US$157 billion.

Impacts of the Ban on the Soil-Applied Fumigant Methyl Bromide.

The loss of the soil fumigant methyl bromide (MeBr) and adoption of soil fumigant alternatives has been challenging for farmers, particularly for those crops in which pathogens previously controlled by MeBr have emerged as significant problems, but it has resulted in some unanticipated benefits for the scientific community and the environment. Applauded as one of the most effective environmental agreements to date, the universally accepted Montreal Protocol on Ozone Depleting Substances has had a significant impact on the environment, reducing the release of halogenated compounds from anthropogenic sources enough to mitigate global warming by an estimated 1.1°C by 2021.

Application of Thymol Vapors to Control Postharvest Decay Caused by and in Grapefruit.

Two of the major postharvest diseases impacting grapefruit shelf life and marketability in the state of Florida (USA) are stem-end rot (SER) caused by and green mold (GM) caused by . Here, we investigated the in vitro and in vivo efficacy of vapors of thymol, a natural compound found in the essential oil of various plants and the primary constituent of thyme () oil, as a potential solution for the management of GM and SER. Thymol vapors at concentrations lower than 10 mg L significantly inhibited the mycelial growth of both pathogens, causing severe ultrastructural damage to conidia.

Yield performance, mineral profile, and nitrate content in a selection of seventeen microgreen species.

Introduction: Originally regarded as garnish greens, microgreens are increasingly valued for their nutritional profile, including their mineral content.

Methods: A study was conducted under controlled environmental conditions utilizing a selection of seventeen microgreen species belonging to seven different botanical families to investigate the genetic variation of macro- and micro-minerals and nitrate (NO ) content. Plants were grown in a soilless system using a natural fiber mat as the substrate.

Soil Amendment and Storage Effect the Quality of Winter Melons ( (Thunb) Cogn.) and Their Juice.

Winter melon fruits were grown in the field using anaerobic soil disinfestation (ASD) and conventional fertilizer alone as the control treatment. Fruits were harvested and stored at 20 °C for 120 d, the juice was processed on day one and day 120, and the effects of soil amendment and 120 d storage on the juice's physical and chemical (sugars, acids, volatile and nutritional compounds) properties were evaluated. Fruit juice extracted from ASD-grown fruit had greater magnitude of zeta potential than the control juice, indicating it was physically more stable than the juice obtained from the control conditions.

Simulated Leaching of Foliar Applied Copper Bactericides on the Soil Microbiome Utilizing Various Beta Diversity Resemblance Measurements.

Copper bactericides are routinely used to control Xanthomonas perforans (XP), causal agent of bacterial spot of tomato. Given the widespread tolerance to copper in XP strains in FL, USA, nanotechnology-based elemental composites have gained interest for their potential applications in agriculture in part due to their enhanced antimicrobial properties and toxicity to copper-tolerant strains. However, little is known about the potential impact of conventional copper bactericides as well as nano-based elemental composites on soil microbial communities, as determined by high-throughput sequencing of the 16S rDNA.

Quantifying the effects of anaerobic soil disinfestation and other biological soil management strategies on nitrous oxide emissions from raised bed plasticulture tomato production.

Soilborne pests are a major obstacle that must be overcome for the production of horticultural crops. Methyl bromide (MBr) was an effective preplanting soil broad-spectrum biocide, but its use has been banned due to its role in depleting the ozone layer. As a result, sustainable alternative methods for controlling soilborne pathogens and pests are needed.

Effects of Harvest Maturity, Refrigeration and Blanching Treatments on the Volatile Profiles of Ripe "Tasti-Lee" Tomatoes.

The interactive effects of six maturity stages and refrigerated storage (chilling)/blanching (heating) treatments on the volatile profiles of ripe tomatoes were studied. A total of 42 volatiles were identified, of which 19 compounds had odor activity values equal to or greater than 1. Of those, "green" and "leafy" aroma volatiles were most abundant.

Anaerobic Soil Disinfestation Efficacy Against Is Affected by Soil Temperature, Amendment Type, Rate, and C:N Ratio.

A meta-analysis of anaerobic soil disinfestation (ASD) efficacy against and f. sp. was conducted emphasizing effects of environment and organic amendment characteristics and pot and field studies conducted on ASD amendment C:N ratio and soil temperature effects on f.

Organic Amendments for Pathogen and Nematode Control.

The loss of methyl bromide as a soil fumigant and minimal advances in the development and registration of new chemical fumigants has resulted in a resurgence of interest in the application of organic amendments (OAs) for soilborne plant pathogen and plant-parasitic nematode management. Significant progress has been made in the characterization of OAs, application of strategies for their use, and elucidation of mechanisms by which they suppress soilborne pests. Nonetheless, their utility is limited by the variability of disease control, expense, and the logistics of introducing them into crop production systems.

Dissipation of fomesafen in fumigated, anaerobic soil disinfestation-treated, and organic-amended soil in Florida tomato production systems.

Background: Fumigated, anaerobic soil disinfestation-treated (ASD), and organic-amended soil management strategies have been investigated as potential methyl bromide (MBr) alternatives for controlling diseases, nematodes, and weeds in soil. Nutsedge and broadleaf weed control using fomesafen has been reported to be comparable to MBr in normal cropping systems. There is no information on the fate of fomesafen used in combination with alternative practices.

Grafting and Paladin Pic-21 for Nematode and Weed Management in Vegetable Production.

Two years of field trials conducted in a infested field evaluated grafting and Paladin Pic-21 (dimethyl disulfide:chloropicrin [DMDS:Pic] 79:21) for root-knot nematode and weed control in tomato and melon. Tomato rootstocks evaluated were; 'TX301', 'Multifort', and 'Aloha'. 'Florida 47' was the scion and the nongrafted control.

Evaluation of Steam and Soil Solarization for Control in Florida Floriculture Crops.

Steam and soil solarization were investigated for control of the root-knot nematode in 2 yr of field trials on a commercial flower farm in Florida. The objective was to determine if preplant steam treatments in combination with solarization, or solarization alone effectively controlled nematodes compared to methyl bromide (MeBr). Trials were conducted in a field with naturally occurring populations of .

Deep Characterization of the Microbiomes of Calophya spp. (Hemiptera: Calophyidae) Gall-Inducing Psyllids Reveals the Absence of Plant Pathogenic Bacteria and Three Dominant Endosymbionts.

Bacteria associated with sap-feeding insect herbivores include not only symbionts that may increase their hosts' fitness but also harmful plant pathogens. Calophya spp. gall-inducing psyllids (Hemiptera: Calophyidae) are being investigated for their potential as biological control agents of the noxious weed, Brazilian peppertree (Schinus terebinthifolia), in Florida.

First Report of Colletotrichum lupini on Lupinus hartwegii and L. mutabilis.

During the 2013 winter cut flower production season, a severe anthracnose epidemic was observed on Lupinus mutabilis (syn L. cruckshanksii) on a commercial flower farm in Martin County, FL. Approximately 50% of the crop was lost to the disease.

Evaluation of Cover Crops with Potential for Use in Anaerobic Soil Disinfestation (ASD) for Susceptibility to Three Species of Meloidogyne.

Several cover crops with potential for use in tropical and subtropical regions were assessed for susceptibility to three common species of root-knot nematode, Meloidogyne arenaria, M. incognita, and M. javanica.

The effect of transitional organic production practices on soilborne pests of tomato in a simulated microplot study.

The perceived risk of pest resurgence upon transition from conventional to organic-based farming systems remains a critical obstacle to expanding organic vegetable production, particularly where chemical fumigants have provided soilborne pest and disease control. Microplots were used to study the effects of soil amendments and cropping sequences applied over a 2-year transitional period from conventional to organic tomato (Solanum lycopersicum) cultivation on the incidence of bacterial wilt caused by Ralstonia solanacearum, purple nutsedge (Cyperus rotundus) reproduction, root galling by Meloidogyne incognita, and soil nematode populations. A continuation of tomato monoculture during the transitional period resulted in a disease incidence of 33%, as compared with 9% in microplots that were rotated with sunn hemp (Crotalaria juncea) and Japanese millet (Echinochloa crusgalli var.

Susceptibility of Several Common Subtropical Weeds to Meloidogyne arenaria, M. incognita, and M. javanica.

Experiments were conducted in the greenhouse to assess root galling and egg production of three root-knot nematode species, Meloidogyne arenaria, M. incognita, and M. javanica, on several weeds common to Florida agricultural land.

First Report of the Root-Knot Nematode Meloidogyne arenaria on Cheeseweed Mallow (Malva parviflora) in the United States.

During a 2010 field trial for examining alternatives to methyl bromide soil fumigation for the production of field-grown cut flowers, weeds were collected for identification and evaluated for their potential as hosts for plant pathogenic nematodes. In one cut flower field located in Martin County, FL, six cheeseweed mallow (Malva parviflora L.) plants were collected that had root-galling typical of infection by a root-knot nematode (Meloidogyne spp.

Differential performance of tropical soda apple and its biological control agent Gratiana boliviana (Coleoptera: Chrysomelidae) in open and shaded habitats.

The leaf feeding beetle Gratiana boliviana Spaeth has been released since 2003 in the southeastern United States for biological control of tropical soda apple, Solanum viarum Dunal. In Florida, G. boliviana can be found on tropical soda apple growing in open pastures as well as in shady wooded areas.

Microplot Evaluation of Rootstocks for Control of Meloidogyne incognita on Grafted Tomato, Muskmelon, and Watermelon.

Microplot experiments were conducted over two years (four growing seasons) to evaluate Meloidogyne incognita resistance in rootstocks used for grafted tomato (Solanum lycopersicum), muskmelon (Cucumis melo), and watermelon (Citrullus lanatus). Three tomato rootstocks; 'TX301', 'Multifort', and 'Aloha', were tested in addition to the nongrafted scion, 'Florida-47'. Two muskmelon rootstocks; Cucumis metuliferus and 'Tetsukabuto' (Cucurbita maxima × Cucurbita moschata) were evaluated with the nongrafted scion 'Athena'.

Cucurbit yellow stunting disorder virus Detected in Pigweed in Florida.

Pigweeds (genus Amaranthus) are problematic weeds in crop production throughout the world and are responsible for significant yield losses in many crops (2). Members of this genus can produce hundreds of thousands of seeds per plant and are also capable of supporting populations of important crop pathogens including viruses, nematodes, fungi, and oomycetes. Thirty-one pigweed samples (tentatively identified as Amaranthus lividus L.

Effects of midas® on nematodes in commercial floriculture production in Florida.

Cut flower producers currently have limited options for nematode control. Four field trials were conducted in 2006 and 2007 to evaluate Midas® (iodomethane:chloropicrin 50:50) for control of root-knot nematodes (Meloidogyne arenaria) on Celosia argentea var. cristata in a commercial floriculture production field in southeastern Florida.

A Nylon Membrane Bag Assay for Determination of the Effect of Chemicals on Soilborne Plant Pathogens in Soil.

A new nylon membrane bag (NMB) assay was developed for studies to determine the effect of chemicals added to soil on survival of soilborne plant pathogens. The rapid and effective assay can be used to study organisms for which there are no selective media or for which a selective medium is expensive or difficult to prepare. This assay consists of placing pathogens inside a bag made of small-pore (0.

Bidens mottle virus and Apium virus Y Identified in Ammi majus in Florida.

Ammi majus (bishop's weed), a member of the Apiaceae, is grown from seed for cut flowers in South Florida. In March 2005, plants were found to be showing virus-like symptoms including mosaic, vein clearing, and leaf rugosity (3) that rendered their flowers unmarketable. Inclusion morphology in epidermal strips from these infected plants indicated the presence of one or more potyviruses.