Sorption and degradation processes of imidacloprid in Florida soils.

Imidacloprid (IDP) is an active ingredient of the Admire brand pesticide used to control the vector (Asian citrus psyllid) that transmits the causative organism Candidatus Liberibacter asiaticus (CLas) for citrus greening or huanglongbing disease. Imidacloprid products are applied via soil drench where citrus roots are mostly concentrated which is between 0 and 60 cm depth. These soil depths exhibit different characteristics that may affect IDP leaching beyond the rooting zone.

Integrated Water, Nutrient, and Pesticide Management of Huanglongbing-Affected Sweet Oranges on Florida Sandy Soils-A Review.

Citrus greening (huanglonbing (HLB)) disease has drastically reduced citrus fruit production in Florida over the last two decades. Scientists have developed sustainable nutrient management practices to live with the disease and continue fruit production. Best pesticide management practices have been devised to reduce the spread of HLB by Asian citrus psyllid (ACP).

Boron, Manganese, and Zinc Sorption and Leaf Uptake on Citrus Cultivated on a Sandy Soil.

Solute fate in soil-plant continuum could either be soil or leaf uptake or leaching beyond the rooting zone. An adsorption coefficient (K) is an important chemical property to describe the interaction between the solute and soil, affecting the solute movement in soils from one point to another. Boron (B), manganese (Mn), and zinc (Zn) uptake are evident in the leaves as a constituent of photosynthesis and other plant body-building mechanisms for growth and development.

Pesticide Sorption to Soilless Media Components Used for Ornamental Plant Production and Aluminum Water Treatment Residuals.

Commercial producers of containerized ornamental plants almost exclusively use soilless media as the substrate for growing the plants. Soilless media are composed primarily of organic materials as opposed to mineral soils. Significant amounts of pesticides can leach from pots containing soilless media to which pesticides have been added as drenches or top-dressings.

How Safe is Chicken Litter for Land Application as an Organic Fertilizer? A Review.

Chicken litter application on land as an organic fertilizer is the cheapest and most environmentally safe method of disposing of the volume generated from the rapidly expanding poultry industry worldwide. However, little is known about the safety of chicken litter for land application and general release into the environment. Bridging this knowledge gap is crucial for maximizing the benefits of chicken litter as an organic fertilizer and mitigating negative impacts on human and environmental health.

Modeling Water and Nutrient Movement in Sandy Soils Using HYDRUS-2D.

Models help to describe and predict complex processes and scenarios that are difficult to understand or measure in environmental management systems. Thus, model simulations were performed (i) to calibrate HYDRUS-2D for water and solute movement as a possible decision support system for Candler and Immokalee fine sand using data from microsprinkler and drip irrigation methods, (ii) to validate the performance of HYDRUS-2D using field data of microsprinkler and drip irrigation methods, and (iii) to investigate Br, NO, and water movement using annual or seasonal weather data and variable fertigation scenarios. The model showed reasonably good agreement between measured and simulated values for soil water content ( = 0.

Imidacloprid soil movement under micro-sprinkler irrigation and soil-drench applications to control Asian citrus psyllid (ACP) and citrus leafminer (CLM).

Imidacloprid (IM) is used to control the Asian Citrus Psyllid (ACP) and citrus leafminer (CLM), which are related to the spread of huanglongbing (HLB or citrus greening) and citrus canker diseases, respectively. In Florida citrus, imidacloprid is mainly soil-drenched around the trees for proper root uptake and translocation into plant canopy to impact ACP and CLM. The objective of this study was to determine the effect of imidacloprid rate, and irrigate amount on concentration of imidacloprid in the soil following drench application to citrus trees in three age classes.

Imidacloprid transport and sorption nonequilibrium in single and multilayered columns of Immokalee fine sand.

Imidacloprid (IMD) is a neonicotinoid pesticide soil-drenched to many crops to control piercing-sucking insects such as the Asian citrus psyllid (ACP). Neonicotinoids are persistent in the environment and transport analyses are helpful estimate leaching potential from soils that could result in groundwater pollution. The objective of this study was to analyze IMD breakthrough under saturated water flow in soil columns packed with three horizons (A, E, Bh) of Immokalee Fine Sand (IFS).

Surfactant-Modified Soil Amendments Reduce Nitrogen and Phosphorus Leaching in a Sand-Based Rootzone.

United States Golf Association putting greens are susceptible to nitrogen (N) and phosphorus (P) leaching. Inorganic soil amendments are used to increase moisture and nutrient retention and may influence N and P leaching. This study was conducted to determine whether N and P leaching could be reduced using soil amendments and surfactant-modified soil amendments.

Imidacloprid Extraction from Citrus Leaves and Analysis by Liquid Chromatography-Mass Spectrometry (HPLC-MS/MS).

A procedure was developed to extract Imidacloprid (IMD) from newly-flushed and fully-expanded citrus leaves. The extraction was conducted in a bullet blender, using a small sample mass (0.5 g of fresh tissue), stainless-steel beads (24 g), and methanol as extractant (10 mL).

Imidacloprid sorption kinetics, equilibria, and degradation in sandy soils of Florida.

Imidacloprid (IMD) is a neonicotinoid insecticide soil-drenched on sandy soils of southwest Florida for the control of Diaphorina citri Kuwayama or Asian citrus psyllid (ACP). The ACP vectors causal pathogens of a devastating citrus disease called citrus greening. Understanding the behavior of IMD in these soils and plants is critical to its performance against target pests.

Effect of tomato packinghouse wastewater properties on phosphorus and cation leaching in a spodosol.

Land application of wastewater is a common practice. However, coarse-textured soils and shallow groundwater in Florida present favorable conditions for leaching of wastewater-applied constituents. Our objective in this study was to determine phosphorus (P) and associated cations (Ca, Mg, K, Na) leaching in a Spodosol irrigated with tomato packinghouse wastewater.

Organochlorine pesticide residues in sediments from the Uganda side of Lake Victoria.

Organochlorine (OC) residues were analysed in 117 sediment samples collected from four bays of the Uganda side of Lake Victoria. The sediments were collected with a corer at a depth of 0-20 cm, and extracted for OC residues using a solid dispersion method. The extracts were cleaned using gel permeation chromatography and analysed for pesticide residues using a gas chromatograph (GC) equipped with an electron capture detector.

Catechol and humic acid sorption onto a range of laboratory-produced black carbons (biochars).

Although the major influence of black carbon (BC) on soil and sediment organic contaminant sorption is widely accepted, an understanding of the mechanisms and natural variation in pyrogenic carbon interaction with natural organic matter (NOM) is lacking. The sorption of a phenolic NOM monomer (catechol) and humic acids (HA) onto BC was examined using biochars made from oak, pine, and grass at 250, 400, and 650 degrees C. Catechol sorption equilibrium occurred after 14 d and was described by a diffusion kinetic model, while HA required only 1 d and followed pseudo-second-order kinetics.

Characterization of adsorption and degradation of diuron in carbonatic and noncarbonatic soils.

The adsorption and degradation of the pesticide diuron in carbonatic and noncarbonatic soils were investigated to better understand the fate and transport of diuron in the environment. Batch adsorption experiments yielded isotherms that were well-described by the linear model. Adsorption coefficients normalized to soil organic carbon content (K(oc)) were lowest for carbonatic soils, averaging 259 +/- 48 (95% CI), 558 +/- 109, 973 +/- 156, and 2090 +/- 1054 for carbonatic soils, Histosols, Oxisols, and Spodosols, respectively.

Use of mixed solvent systems to eliminate sorption of strongly hydrophobic organic chemicals on container walls.

Strongly hydrophobic organic chemicals (SHOCs) can be defined as neutral organic chemicals that have soil organic carbon (OC) normalized sorption coefficient (K(OC)) >10,000. Sorption isotherms of SHOCs are normally measured in aqueous systems to determine K(OC). Since SHOCs can adsorb on container walls leading to overestimation of K(OC), we used mixed solvent systems to characterize this potential error.

A simple high performance liquid chromatography method for analyzing paraquat in soil solution samples.

A high performance liquid chromatography (HPLC) method with UV detection was developed to analyze paraquat (1,1'-dimethyl-4,4'-dipyridinium dichloride) herbicide content in soil solution samples. The analytical method was compared with the liquid scintillation counting (LSC) method using 14C-paraquat. Agreement obtained between the two methods was reasonable.

Spatial distribution of DDT in sediments from estuarine rivers of central Florida.

Sediments may act as both a carrier for and a potential source of contaminants such as toxic organics in aquatic environments. This study investigated the spatial distribution of the pesticide DDT [1,1, 1-trichloro-2,2-bis(p-chlorophenyl)ethane] in sediments from the Cedar and Ortega Rivers located in the lower St. Johns River basin, Florida, USA, using field measurements and three-dimensional kriging analysis.