Environmental fate and exposure; neonicotinoids and fipronil.

Environmental risk assessment scheme for plant protection products

Glyphosate decreases mycorrhizal colonization and affects plant-soil feedback

Pollinators and other insects are experiencing an ongoing worldwide decline. While various environmental stressors have been implicated, including pesticide exposure, the causes of these declines are complex and highly debated. Fungicides may constitute a particularly prevalent threat to pollinator health due to their application on many crops during bloom, and because pollinators such as bees may consume fungicide-tainted pollen or nectar. In a previous study, consumption of pollen containing the fungicide Pristine® at field-relevant concentrations by honey bee colonies increased pollen foraging, caused earlier foraging, lowered worker survival, and reduced colony population size. Because most pollen is consumed by young adults, we hypothesized that Pristine® (25.2% boscalid, 12.8% pyraclostrobin) in pollen exerts its negative effects on honey bee colonies primarily on the adult stage. To rigorously test this hypothesis, we used a cross-fostering experimental design, with bees reared in colonies provided Pristine® incorporated into pollen patties at a supra-field concentration (230 mg/kg), only in the larvae, only in the adult, or both stages. In contrast to our predictions, exposure to Pristine® in either the larval or adult stage reduced survival relative to control bees not exposed to Pristine®, and exposure to the fungicide at both larval and adult stages further reduced survival. Adult exposure caused precocious foraging, while larval exposure increased the tendency to forage for pollen. These results demonstrate that pollen containing Pristine® can induce significant negative effects on both larvae and adults in a hive, though the magnitude of such effects may be smaller at field-realistic doses. To further test the potential negative effects of direct consumption of Pristine® on larvae, we reared them in vitro on food containing Pristine® at a range of concentrations. Consumption of Pristine® reduced survival rates of larvae at all concentrations tested. Larval and adult weights were only reduced at a supra-field concentration. We conclude that consumption of pollen containing Pristine® by field honey bee colonies likely exerts impacts on colony population size and foraging behavior by affecting both larvae and adults.

Flupyradifurone (Sivanto) is a novel systemic insecticide from the butenolide class developed by Bayer. Based on available data (USEPA 2014), this insecticide appears to have a favorable safety profile for honey bee colonies. As a result, the label permits the product to be applied during prebloom and bloom in various crops, including citrus, except when mixed with azole fungicides during the blooming period. We placed 24 honey bee (Apis mellifera L.) colonies adjacent to eight flowering buckwheat (Fagopyrum esculentum Moench) fields that either had been sprayed with the maximum label rate of flupyradifurone or with water only (control fields), with three colonies placed adjacent to each field. We conducted colony strength assessments during which the number of adult bees, eggs, uncapped brood cells, capped brood cells, food storage cells, and weights of honey supers and brood chambers were determined prior to, during, and after the flowering period. We also analyzed bee-collected pollen and nectar for flupyradifurone residues. Overall, there were no differences in any colony strength parameter for colonies placed at control and flupyradifurone-treated buckwheat fields. Residue analyses showed that pollen (x = 565.8 ppb) and nectar (x = 259.4 ppb) gathered by bees on fields treated with flupyradifurone contained significantly higher flupyradifurone residues than did bee bread and unprocessed nectar collected by bees from control fields (75% of samples <LOD). Within the conditions set forth by our experimental design, our collective data suggest no adverse effects of flupyradifurone on honey bee colonies when following label directions.

Plant growth regulators (PGRs) are extensively used in modern agriculture to modify plant developmental processes, enhance productivity, and improve crop quality under increasingly variable environmental conditions. While their agronomic benefits are well established, growing attention has been directed toward understanding their broader environmental implications. In this current review, we analyze recent research published over the last five years to evaluate the environmental behavior and ecological impacts of widely used natural and synthetic plant growth regulators. Particular emphasis is placed on their persistence and mobility in soil and water, their interactions with soil microbial communities, and their effects on non-target terrestrial and aquatic organisms. Recent advances in analytical detection and ecotoxicological assessment have revealed that several PGRs, despite being applied at low doses, may exhibit prolonged environmental residence and subtle biological effects, particularly following repeated applications. Alterations in soil enzyme activity, shifts in microbial community structure, and growth disturbances in non-target plants and aquatic primary producers have been increasingly reported. The review also discusses emerging strategies aimed at reducing environmental risks, including precision application technologies, the development of biodegradable regulators, and improved regulatory frameworks. Overall, these findings highlight the need for integrated risk assessment approaches and long-term field studies to support the sustainable use of plant growth regulators in agroecosystems.

Simple SummarySome insects are beneficial to plants because they eat pest insects and disease-causing fungi; integrating the use of these insects into pest management can help to reduce the need for costly pesticide applications. Twenty-spotted ladybeetles eat plant pathogenic fungi, which helps to reduce disease severity for many economically important crops. In this study, we applied a systemic insecticide to the roots of pumpkin plants and monitored to see if it would be detectable in the spores of a plant pathogenic fungus and whether the insecticide-tainted fungal spores would hurt the ladybeetle larvae. We were able to chemically detect the systemic insecticide in the fungal spores up to 21 days after the plants had been treated with the fungus. We found that the ladybeetles raised on infected plants that had been treated with the systemic insecticide died more rapidly that ladybeetles that had been raised on uninfected or untreated plants. This study is the first to show that systemic insecticides can move from the roots of a plant, into a plant pathogenic fungus, and then have negative effects on a fungus-eating insect. It suggests that growers and land managers need to carefully consider the unintended consequences of insecticide applications.Applications of systemic pesticides can have unexpected direct and indirect effects on nontarget organisms, producing ecosystem-level impacts. We investigated whether a systemic insecticide (imidacloprid) could be absorbed by a plant pathogenic fungus infecting treated plants and whether the absorbed levels were high enough to have detrimental effects on the survival of a mycophagous beetle. Beetle larvae fed on these fungi were used to assess the survival effects of powdery mildew and imidacloprid in a factorial design. Fungal conidia were collected from treated and untreated plants and were tested for the presence and concentration of imidacloprid. The survival of beetles fed powdery mildew from imidacloprid-treated leaves was significantly lower than that of the beetles from all other treatments. Imidacloprid accumulated in fungal conidia and hyphae was detected at levels considered lethal to other insects, including coccinellid beetles. Water-soluble systemic insecticides may disrupt mycophagous insects as well as other nontarget organisms, with significant implications for biodiversity and ecosystem function.

Herbicides have been extensively researched due to widespread use in agriculture, consequently raising concerns regarding their environmental impact and potential adverse effects on non-target organisms, including humans. Nicosulfuron is a post-emergence herbicide used to control annual or perennial grasses and broad-leaved weeds. In contrast, S-metolachlor is primarily employed as a pre-emergence herbicide for managing annual grasses and certain broad-leaved weeds in intensive cropping systems. This study aimed to assess the effects of two commercial herbicides, one based upon nicosulfuron and the other upon S-metolachlor active ingredients, on the early developmental stages of the plant models Lactuca sativa L. (lettuce), Raphanus sativus (radish), Pennisetum glaucum (L.) R. Br. (millet), and Triticum aestivum (wheat), as evidenced from germination and seedling development bioassays. Results indicated that all plant models exhibited phytotoxic responses, including inhibited germination, reduced germination speed index, and impaired seedling growth and development, ultimately leading to decreased fresh weight. Among the plant species tested, T. aestivum was the most sensitive, while R. sativus was the least affected. Data suggest that nicosulfuron and S-metolachlor-based herbicides exert significant phytotoxic effects on non-target plants, offering valuable insights for future research on the environmental impacts of these substances.

Biological control of invasive apple snails by two species of carp: Effects on non-target species matter

Predicting sublethal effects of herbicides on terrestrial non-crop plant species in the field from greenhouse data

A new pseudo-partition coefficient based on a weather-adjusted multicomponent model for mushroom uptake of pesticides from soil

Consumption of field-realistic doses of a widely used mito-toxic fungicide reduces thorax mass but does not negatively impact flight capacities of the honey bee (Apis mellifera)

This guide addresses the effects of various types of pesticides on nontarget organisms, including natural enemies and beneficial organisms such as honey bees, wildlife, fish, and nontarget plants. This document is PI-85, one of a series of the Pesticide Information Office, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. Original publication date: November 2005.

Pesticides are an integral part of agriculture as Florida's climate fosters an environment conducive to major pest outbreaks throughout the entire year. Our environment also is favorable for the development and presence of beneficial organisms that positively affect our agricultural production and enhance our wildlife and plant communities. This revised 7-page guide addresses the effects of various types of pesticides on nontarget organisms, including natural enemies and beneficial organisms, such as honeybees, wildlife, fish, and nontarget plants. Written by Frederick M. Fishel and published by the UF Department of Agronomy, April 2011.

Seasonal variability in physiology and behavior affect the impact of fungicide exposure on honey bee (Apis mellifera) health

Potential detrimental impacts of neonicotinoids on non-target organisms, especially bees, have been subject to a wide debate and the subsequent ban of three neonicotinoids by the EU. While recent research has fortified concerns regarding the effects of neonicotinoids on ecosystem service (ES) providers, potential impacts have been considered negligible in systems with a relatively small proportion of arable land and thus lower the use of these pesticides. In this paper we argue that there is not sufficient information to assess magnitude and extent of neonicotinoid application, as well as potential non-target impacts on ES providers in grass-dominated systems with frequent land-use change. Using Ireland as an example, we show that the highly dynamic agricultural landscape, in conjunction with estimated persistence times of neonicotinoids in soils, may lead to a much larger area (18.6 ± 0.6% of the Irish agricultural area) exposed to these pesticides than initially assumed. Furthermore we present a number of important gaps in current research regarding the impacts of neonicotinoids on ES providers in such systems.