also see fludioxonil, soils,  Bee Die-off, Sulfoxaflor and flupyradifurone, mixture effects, digestive tract/microbiome,  legislation/regulatory/USA, resistance, digestive tract/microbiome

Strawberries Lose Their Sweetness, Aroma, and Taste after Being Sprayed with Chemical Fungicides, Study Finds    (Beyond Pesticides, March 1, 2023) 'Fungicides sprayed on chemically farmed strawberries reduce their flavor quality, according to research published in the Journal of Agricultural and Food Chemistry this week.   Differences in sugar content are not minute, with the difenconazole expressing 10% less fructose, and boscalid group 25% less.  At the same time, levels of titratable acid increase in the fungicide treatments, and display the lowest sugar-acid ratio; the control group expresses the highest.   Treated strawberries show lower levels of flavonoid content and a lower number of total phenols compared to the control. Analysis found evidence that treated strawberries also have higher levels of oxidative stress

Neonicotinoids Combined with Other Pesticides Elevate Hazards to Honey Bee  (Beyond Pesticides, February 22, 2023)   'Among the eight pesticides tested, honey bee toxicity was as follows from most to least toxic: the neonicotinoid insecticide thiamethoxam, the organophosphate insecticide dimethoate, the carbamate insecticide methomyl, the synthetic pyrethroid insecticides permethrin, and then cypermethrin, the triazole fungicide tetraconazole, and the synthetic pyrethroids cyfluthrin and then esfenvalerate. These results did change based on different treatment lengths, yet thiamethoxam was found to remain the most toxic throughout all studies.  In the study, scientists evaluate a total of 98 different mixtures, from binary combinations of two different chemicals to octonary combinations of all eight different pesticides. Within these tests, approximately 30% of these were found to be synergistic to honey bees, exhibiting toxicity greater than each individual material in the mixture.  Perhaps the most concerning interaction came from combinations that included thiamethoxam and the fungicide tetraconazole. Any variation of pesticide combinations that include these two chemicals have a roughly 55% chance of exhibiting synergistic toxicity to honey bees.'

Common Fungicide Adds to Growing List of Pesticides Linked to Gastrointestinal and Microbiome Damage   (Beyond Pesticides, January 26, 2023) A study published in Food Safety and Toxicology finds that the widely used fungicide azoxystrobin (AZO), used in food production and turf management, can disrupt the function of the intestinal (colonic) barrier responsible for the absorption of nutrients and defense against harmful substances.  The results reveal AZO exposure altered the metabolic profile of microbes in the gut, inducing gut dysbiosis, leading to structural damage of the colon and colonic inflammatory response. Although the L-AZO (low dose) treatment group experiences no changes in body weight compared to the control group, the H-AZO (high dose) treatment group has significantly reduced body weight and weight gain. SNAP comment: Azoxystrobin does not seem to be currently registered by the PMRA in Canada.

Fungi that Survive Fungicide Use Multiply and Thrive   (Beyond Pesticides, November 22, 2022) 'Fungus that survive a fungicide application may be able to multiply and thrive, putting plant yields at risk. This finding comes from research recently published by scientists at University of Illinois, focusing on the impact of fungicide use on soybean yields and the disease Septoria brown spot, caused by the fungus Septoria glycines. The research underlines the danger of preventive chemical applications in an attempt to protect yield and shows how precarious pesticide use can be when subject to the complexity seen in field conditions.  The takeaway is to not proceed down the path of incessant preventive spraying but instead to reconsider the need for any pesticide application in the context of complex processes occurring on the leaf surface of soybean plants. “But what I’m learning from the study is that we don’t know exactly what we’re doing when we apply fungicides to protect yield. We need to learn more about the unintended effects of chemical applications.” and develop natural bio- alternatives.   “When we applied the fungicide, most of the fungi on plant surfaces decreased,” said Santiago Mideros, PhD, study coauthor and professor at the University of Illinois. “But a few of the fungi increased, Septoria among them. It was very surprising.”    Scientists employed a mixture of the fungicides fluxapyroxad and pyraclostrobin, which are commonly used throughout the Midwest to manage fungal diseases in soybean crops.'   SNAP Comments: As of 7 December 2022, 22 fluxapyroxad and 53 pyraclostrobin pesticides are registered in Canada.

EPA’s Deficient Pesticide Analysis Contributes to Ecological Decline   (Beyond Pesticides, November 21, 2022) Once again, the Environmental Protection Agency (EPA) has registered a new pesticide without performing a thorough review of its impacts on biodiversity as well as threatened and endangered species. Inpyrfluxam was registered in 2020 and only after being sued by the Center for Biological Diversity for failure to comply with the Endangered Species Act (ESA) did EPA commit to completing draft effects determinations by Fall 2022.   SNAP Comment: As of 7 December, 2022, 9 Inpyrfluxam (a fungicide) are currently registered in Canada. I doubt we did a better job than the US EPA regarding its dangers to biodiversity. 

Pesticide Mixtures Reduce Life Span of Honey Bees, Damage Gut Microbiome    (Beyond Pesticides, November 1, 2022) Study done with field relevant concentrations. 'Honey bees exposed to a combination of multiple pesticides suffer a reduced lifespan and experience adverse changes to their gut microbiome, increasing susceptibility to pathogens and disease. This finding comes from a study published recently in Science of the Total Environment, which examines the interactions between the insecticides flupyradifurone and sulfoxaflor and the fungicide azoxystrobin on honey bee health.   As the present study reveals, pesticide risk assessments do not inadequately capture the range of harm that can result when pesticides are combined, necessitating a shift toward safer, alternative, and regenerative organic farming systems that do not use these dangerous chemicals.For the initial experiment on individual bees, those exposed to flupyradifurone fared the worst, experiencing significantly reduced survival (50% reduction). The addition of azoxystrobin did not significantly add to this effect. However, with sulfoxaflor, it did. Bees subjected to sulfoxaflor and azoxystrobin in combination experienced significantly reduced survival when compared to a sole sulfoxaflor exposure.'     All experimental groups 'show significantly increased abundance of Serratia spp. This rod-shaped bacteria can serious harm honey bee fitness. “These bacteria are pathogenic and harmful to bees’ health,” said Dr. Al Naggar. “They can make it harder for the insects to fight off infection, leading to premature death.”

Fungicide Use Harms Beneficial Soil Life, Jeopardizes Crop Yields  (Beyond Pesticides, October 25, 2022) 'Fungicide use harms soil and jeopardizes crop yields by reducing the prevalence of arbuscular mycorrhizal fungi (AMF), according to recent research published in Nature Ecology and Evolution. AMF are important fungi that form symbiotic relationships with plants in both natural and cropland soils, and their presence helps facilitate nutrient uptake, particularly for phosphorus. The natural grassland soils took up 64% more 33P (phosphorus, an essential crop nurient) than soils from the cropland sites. Analysis also finds that AMF richness and microbial biomass was lower in croplands soils by 41% and 29% respectively, with these soils having significantly more available P than in natural grassland soil.  Cropland soils that were not treated with a fungicide had an average P transfer 2.3 times greater than soils that had three fungicide applications over the last year in the study. In fact, P recovery rates decreased in tandem with the number of each additional fungicide application. Unsurprisingly, scientists found evidence for fungicides diminishing AMF richness, thereby reducing P uptake.' This experiment was done of the weed Plantago lanceolata because of its known ability to form associations with a range of different AMF species. Most domesticated crops grown today are not bred to have a symbiotic relationship with AMF.