Rotam (China)

Considering the vital role of rooted macrophytes in the aquatic ecosystem, validating assumptions on the interactive effects of herbicides with different modes of action at an environmentally relevant mixture ratio is necessary. We investigated the effects of diflufenican (a carotenoid biosynthesis inhibitor) and iodosulfuron-methyl-sodium (IMS; an acetolactate synthase inhibitor) in a 14-day growth inhibition experiment with Myriophyllum spicatum, wherein single compounds and their combination were tested in parallel (n = 84). The assessment was done using three different methods: significance testing, model deviation ratio (MDR), and mixture interaction factor (MIF). Interactions relative to both concentration addition and independent action were assessed via significance testing. This revealed that diflufenican and IMS acted antagonistically relative to both models for fresh weight and total shoot length (p < 0.05) and that there was slight synergism for the number of side shoots (p < 0.001) relative to concentration addition. The MDR and MIF can only assess interactions relative to the concentration addition model. According to MDR, the mixture appeared to show no interaction (neither antagonistic nor synergistic), whereas the MIF method revealed that the compounds acted antagonistically for fresh weight and that there was a slight synergism for total shoot length and number of side shoots. We conclude that inferences about mixture toxicity interactions are method- and endpoint-dependent, which can have implications for regulatory mixtures assessment. Environ Toxicol Chem 2022;41:2209-2220. © 2022 SETAC.

Recent studies have revealed multiple roles of insect-associated microbes such as lignin degradation, entomopathogen inhibition, and antibiotic production. These functions improve insect host fitness, and provide a novel source of discovering beneficial microbes for industrial and agricultural production. Previously published research found that in the symbiosis formed by the dipteran pest Delia antiqua (Meigen) (Diptera: Anthomyiidae) and its associated bacteria, the bacteria showed effective inhibition of one fungal entomopathogen, Beauveria bassiana. The antifungal activity of those associated bacteria indicates their potential to be used as biocontrol agents for fungal phytopathogens. In this study, we first isolated and identified bacteria associated with D. antiqua using a culture-dependent method. Second, we tested the antifungal activity of these bacteria against four phytopathogens including Fusarium moniliforme, Botryosphaeria dothidea, and two Fusarium oxysporum strains using the dual-culture method. In total, 74 species belonging to 30 genera, 23 families, eight classes, and four phyla were isolated and identified. Among those bacteria, Ochrobactrum anthropi, Morganella morganii, Arthrobacter sp. 3, and Acinetobacter guillouiae showed significant volatile inhibition activity against F. moniliforme, B. dothidea, and both F. oxysporum, respectively. Moreover, bacteria including Rhodococcus equi, Leucobacter aridicollis, Paenibacillus sp. 3, and Lampropedia sp. showed significant contact inhibition activity against F. moniliforme, B. dothidea, and both F. oxysporum. Our work provides a new source for discovering biocontrol agents against phytopathogens.

Agrochemicals are widely used in the present day agricultural practices and many non-targeted species like honey bees are affected by these agrochemicals and getting declined in the nature.To prevent this, detoxification mechanism needs to be studied and implemented in future aspects to protect the honey bees.Honeybee is a member of the genus Apis, involved in the production and storage of honey, construction of perennial, colonial nests from wax. Species of Apis mellifera pollinate a large variety of plants. Of all the honey bee species, only A.mellifera has been used extensively for commercial pollination of crops and other plants. Bees suffer serious effects from toxic chemicals in their environments. These include various synthetic chemicals, such as insecticides and fertilizers, as well as a variety of naturally occurring chemicals from plants. Insecticides are considered the major factors for the current decline in bee populations. However, detoxification mechanisms in healthy, unstressed honey bees are poorly characterized. A substance called p-coumaric acid specifically up-regulates all classes of detoxification genes as well as select antimicrobial peptide genes. This up-regulation has functional significancein that adding p-coumaric acid to a diet of sucrose increases midgut metabolism of coumaphos, a widely used in-hive acaricide, by 60%. As a major component of pollen grains, pcoumaric acid is ubiquitous in the natural diet of honey bees and mayfunction as a nutraceutical regulating immune and detoxification processes. In less than 20 years, neonicotinoids have become the most widely used class of insecticides with a global market share of more than 25%. These chemicals mimic the acetylcholine neurotransmitter and are highly neurotoxic to insects. At field realistic doses, neonicotinoids cause a wide range of adverse sublethal effects in honeybee andbumble bee colonies which affects colony performance through impairment of foraging success, brood and larval development, memory and learning, damage to the central nervous system, susceptibility to diseases, hive hygiene etc. The worldwide production of neonicotinoids is still mounting. Therefore a transition to pollinator-friendly alternatives to neonicotinoids is urgently needed for the sake of the sustainability of pollinator ecosystem services.