Studies on the abilities of uptake and translocation from root to shoot of pesticides in soil

The uptake experiments with pesticides were performed to clarify differences among plant species, and the influence of growth stages and conditions on the uptake and translocation ability of pesticides. There were 2–10-fold differences among plant species in the root and shoot concentrations of each pesticide, and shoot concentrations of pesticides in Brassica rapa L. var. perviridis were relatively high. In addition, the changes in shoot concentrations with growth stage of B. rapa were affected by root system development. The influence of temperature on uptake and translocation ability differed for each pesticide, while uptake and translocation ability were high for short day lengths. This indicated that plant uptake and translocation of pesticides were affected by root system development and growth conditions such as temperature and day length, not only the relationships to the chemical’s properties and behavior of organic chemicals in the soil.     

Influence of Atrazine and Roundup pesticides on biochemical and molecular aspects of Biomphalaria alexandrina snails

The excessive use of pesticides in agriculture has sparkled the interest of scientists in investigating the harmful effects of these compounds. The present study evaluates the pesticides Atrazine and Roundup (glyphosate) on biochemical and molecular aspects of Biomphalaria alexandrina snails. The results showed that LC₁₀ of these two pesticides caused considerable reduction in survival rates and egg production of treated snails. Additionally, Atrazine proved to be more toxic to B. alexandrina snails than Roundup. In treated snails, glucose concentration (GL) in the hemolymph as well as lactate (LT) and free amino acid (FAA) in soft tissues of treated snails increased while glycogen (GN), pyruvate (PV), total protein (TP), nucleic acids (DNA and RNA) levels in snail’s tissues decreased. The activities of glycogen phosphorylase (GP), superoxide dismutase (SOD), catalase (CAT) and glutathione reductase (GR), succinic dehydrogenase (SDH), acetylcholinesterase (AChE), lactic dehydrogenase (LDH) and phosphatases (ACP and ALP) enzymes in homogenate of snail’s tissues were reduced in response to the treatment with the two pesticides while lipid peroxide (LP) and transaminases (GOT and GPT) activity increased (P < 0.001). The changes in the number, position and intensity of DNA bands induced by pesticides may be attributed to the fact that pesticide can induce genotoxicity through DNA damage. It was concluded that the pollution of the aquatic environment by Atrazine and Roundup pesticides, would adversely affect the metabolism of the B. alexandrina snails, and have adverse effects on its reproduction.     

白腐真菌降解农药研究进展

白腐真菌是一类腐生的丝状真菌，其分泌的非特异性胞外氧化酶可以降解多种结构不同、毒性较高且难以降解的有机农药。本研究总结了白腐真菌对有机氯、有机磷、氨基甲酸酯和拟除虫菊酯类农药的降解效果，并对部分农药的降解途径研究进展进行了综述，分析了白腐真菌降解农药的影响因素，同时对其应用前景进行了展望。     

Temporal and regional variability of cumulative ecological risks of pesticides in Japanese river waters for 1990–2010

We quantitatively evaluated the cumulative ecological risks from multiple pesticides used in paddy fields in Japan. Moreover, we visualized the temporal and regional variability of those risks for 1990–2010. Considering the region-specific parameters of environmental conditions, region-specific predicted environmental concentrations were estimated at 350 river-flow monitoring sites in Japan. Then the multi-substance potentially affected fraction (msPAF) was calculated as a risk index of multiple pesticides by using the computation tool NIAES-CERAP. The median msPAF values for insecticides and herbicides decreased by 92.4% and 53.1%, respectively, from 1990 to 2010. This substantial reduction in ecological risk was attributed to the development of low-risk pesticides by manufacturers, the efforts of farmers in risk reduction, and tighter regulation by the Japanese government. In particular, the substantial reduction of the ecological risk from insecticides was largely due to the decrease in the use of organophosphorus insecticides.     

农田尾菜发酵过程中农药残留变化特征

基于尾菜中存在农药残留的现状,以设施农业尾菜黄瓜秧为研究对象,采用气相色谱法和超高效液相色谱-串联质谱法检测了尾菜黄瓜秧在静态好氧发酵过程中多菌灵、吡虫啉、哒螨灵等50种农药残留的动态变化,并分析发酵重要影响因子堆高对农药残留消解的影响。结果表明:在尾菜黄瓜秧中共检测出腐霉利、多菌灵、嘧菌酯、苯醚甲环唑、烯酰吗啉、虫螨腈、吡虫啉、啶虫脒和哒螨灵9种农药残留,其中多菌灵平均残留量最高,达11.2 mg/kg,其他8种农药平均残留量在0.042~0.89 mg/kg之间。在发酵的24 d中,不同堆高条件下9种农药的消解规律均符合一级反应动力学方程,但不同农药半衰期差异较大,其中吡虫啉的平均半衰期最长,为28.9 d,多菌灵的平均半衰期最短,为10.2 d;不同堆高处理中农药的消解速率也有差异,总体上在2.5 m堆高下各农药的消解率最高、半衰期最短。本研究结果可为尾菜发酵参数优化、农业废弃物的高效资源化利用以及研发基于尾菜发酵产物的有机蔬菜专用有机肥提供理论支撑。     

Influence of pesticides on the growth rate and plant-growth promoting traits of Gluconacetobacter diazotrophicus

The in vitro study to examine the effect of different pesticides on the growth and survival of Gluconacetobacter diazotrophicus strain PAL5 was carried out. Monocrotophos, Lindane and Dichlorvos had the most lethal actions against Gluconacetobacter grown on LGIP medium, while Endosulphan, Chlorpyriphos, and Malathion effects were intermediate. Herbicides generally appeared to have no adverse effect on the growth and survival of Gluconacetobacter in the medium except for the concentrations exceeding recommended rates. Fungicides, except Ridomil, had a slight effect on the growth of Gluconacetobacter at recommended dose. With the various pesticides used, the cell morphology was affected to a larger extent resulting in larger number of pleomorphic cells. Further their influence on the physiological traits like nitrogenase activity, indole-3-acetic acid, gibberellin A₃ production, and phosphate and zinc solubilizing activity are discussed.     

三种双酰胺类杀虫剂对小地老虎和 蚯蚓的选择毒性

为筛选出高效安全的土壤处理杀虫剂,室内采用浸叶法比较了溴氰虫酰胺、氯虫苯甲酰胺、氟虫双酰胺与8种常规杀虫剂对小地老虎的毒力,用滤纸接触法和人工土壤法分别测定了11种药剂对蚯蚓的急性毒性,并通过盆栽试验比较了其对小地老虎和蚯蚓的选择毒性.结果表明,3种双酰胺类杀虫剂对小地老虎的室内毒力明显高于其它8种对照药剂,对蚯蚓的LC50均属于低毒级,其中以溴氰虫酰胺的毒力选择性最高.盆栽试验中双酰胺类药剂防虫效果均低于其它对照药剂,10％溴氰虫酰胺可分散油悬浮剂保苗效果显著高于5％氯虫苯甲酰胺悬浮剂和20％丁硫克百威乳油,且双酰胺类药剂对蚯蚓没有明显致死作用.说明在棉田选择溴氰虫酰胺能够控制小地老虎的危害.     

Degradation and leaching potential of pesticides in biobed systems

Biobeds provide a potential solution to pesticide contamination of surface waters arising from the farmyard. Previous work has shown that biobeds can effectively treat spills and splashes of pesticide. This study investigated the potential for biobeds to treat much larger volumes and amounts of pesticide waste not only arising from spills but also from washing processes. Two systems were assessed using a range of pesticides at the semi-field scale, ie a lined biobed system and an unlined system. Studies using the lined biobeds demonstrated that water management was crucial, with biobeds needing to be covered to exclude rain-water. Once covered, the top of the biobed became hydrophobic, restricting moisture loss and resulting in saturated conditions at depth. The drying out of the top layer coincided with a measured decrease in microbial biomass in the treated biobeds. Applied pesticides were effectively retained within the 0-5 cm layer. Whilst all pesticides tested degraded, low moisture content and microbial activity meant degradation rates were low. Studies using unlined biobeds showed that only the most mobile pesticides leached, and for these > 99% was removed by the system, with a significant proportion degraded within 9 months. Peak concentrations of the two most mobile pesticides did however exceeded the limits that are likely to be required by regulatory bodies. However, it is thought that these limits could be reached by optimisation of the system.     

Biota uptake of pesticides by selected plant species; the case study of Kilombero sugarcane plantations in Morogoro Region, Tanzania

This paper reports on biota uptake of pesticides by selected plant species from soil in which they are grown. The study was conducted at Kilombero sugarcane plantations and environs, Morogoro Region, Tanzania. Three species of the plant materials were collected namely sugarcane (Saccharum officinarum), guinea grass (Panicum maximum) and mango leaves (Mangifera indica). The sugarcane and guinea grass were used to reveal the plant uptake in the plantations whereas mango leaves were used to represent the environs. GPC cleaned sample extracts were analysed by GC-ECD and GC-NPD and the results confirmed using GC-MS. A total of 16 different pesticide residues were detected in soil samples and only 11 pesticide residues were detected in flora samples. o,p′-DDT had the highest concentration of all detected pesticides in soil samples with a mean concentration of 21.04 μg/kg d.w. whereas the highest concentrations of 17.16 μg/kg d.w. was recorded for p,p′-DDD in flora samples. The other DDT metabolites detected in soil samples were p,p′-DDT, p,p′-DDE, o,p′-DDE, p,p′-DDD and o,p′-DDD with concentration ranging from 2.00 to 18.30 μg/kg d.w. whereas the other pesticides detected in flora samples were p,p′-DDT α-endosulfan and γ-HCH with a mean concentration range of 3.21 to 13.54 μg/kg d.w. The paired sample t-test showed no significant difference between the concentrations of pesticides in flora and those found in soil.     

Can Batesian mimicry help plants to deter herbivores?

Several authors have suggested that edible plants could avoid herbivory by mimicking olfactory cues of toxic plants. However, very few studies have been carried out to test this hypothesis. The aims of the present study were to identify the volatiles of three clover species and to test whether a species lacking chemical defences, such as red clover, could avoid being grazed by rabbits by mimicking the volatiles of the cyanogenic white clover. Two main volatiles were identified in all three clover species, and a further two volatiles were present in white clover only. Rabbits presented with a choice between white clover, red clover and red clover sprayed with white clover extract ate significantly more red clover than white or white-flavoured red clover. The results suggest that the volatiles of toxic plants could be used and exploited as a source of natural, safe and effective repellents to control the impact of pest herbivores on plants.     

Movement of pesticides to surface waters from a heavy clay soil

A field experiment at Cockle Park, Northumberland on a clay loam soil (Dunkeswick series) cropped with winter wheat investigated the effects of drainage and season of application on pesticide movement. Isoproturon, mecoprop, fonofos and trifluralin were applied in two consecutive seasons at normal agricultural rates to three hydrologically isolated plots each of 0.25 ha. Two of the plots were mole-drained and the third was an undrained control. Surfacelayer flow and drainflow from each plot were monitored at 10-min intervals. Samples of flow were analysed for pesticides to evaluate transport of applied chemicals from the site. Despite widely differing properties (K_oc 20–8000 ml g^?1, t_1/2 10–60 days), all four pesticides were found in surface-layer flow and mole drainflow from the site. Maximum concentrations of pesticides in flow ranged from 0.1 to 121 μg litre^?1 (aqueous phase) and < 0.2 to 48 μg litre^?1 (particulate phase). Over two contrasting seasons, total losses of pesticides in flow followed total amounts of flow and were approximately four and five times larger, respectively, in 1990/91 than in 1989/90. The maximum loss occurred from the undrained plot and was 2.8 g isoproturon (0.45% of that applied). Total losses of autumn-applied pesticides from an undrained plot were up to four times greater than losses from a mole-drained plot. Mole drainage decreased movement of pesticides from this slowly permeable soil by reducing the amount of surfacelayer flow. Maximum concentrations of mecoprop and isoproturon in drainflow were 10–20 times larger following spring application than after application in autumn. Bypass flow down soil cracks was an important process by which pesticide was lost from the site, with transport to the drainage system via mole channels (55 cm depth) after less than 0.5 and 6.7 mm net drainage in the two winters.     

七种杀虫剂对暗黑鳃金龟成虫和幼虫的毒力及田间防控效果

为筛选防治暗黑鳃金龟Holotrichia parallela的有效药剂,用浸虫法测定了7种药剂对暗黑鳃金龟幼虫的毒力,分别采用浸虫法、浸叶法、药膜法测定了7种药剂对其成虫的毒力,并通过大田试验作了进一步验证。浸虫法测得高效氯氟氰菊酯对成虫的毒力最高,LC₅₀值为1.38 mg/L;浸叶法测得辛硫磷毒力最高,为42.05 mg/L;药膜法测得毒死蜱毒力最高,为18.51 mg/L。其中,高效氯氟氰菊酯毒力值变化最大,浸虫法毒力是浸叶法毒力的61.86倍;氯虫苯甲酰胺、氟虫腈在3种生测方法中毒力相当,但均较低。丁硫克百威对暗黑鳃金龟幼虫的毒力最高,LC₅₀值为7.29 mg/L。田间试验结果显示,35%辛硫磷微囊悬浮剂4 500 g/hm²(有效成分,余同)防效达80.66%,对花生的保果、增产幅度分别为77.90%、17.56%;30%毒死蜱微囊悬浮剂2 250 g/hm²、20%丁硫克百威乳油3 000 g/hm²与辛硫磷防效相当,且显著高于其它药剂。因此,选用以上药剂于7月中下旬花生封垄前田间灌墩可以有效减轻暗黑鳃金龟为害。     

Pesticide residues in soil and foodstuff I. Chlorinated pesticides in cattle feed and milk produced in orchard and non-orchard areas

Milk, hay and silage produced in orchard and non-orchard areas have been analysed for their content of chlorinated pesticides. The residue levels in milk produced in orchard areas were about double those in milk produced in non-orchard areas. The levels in hay were much higher (30% up to sevenfold) in the hay produced in orchard areas and the levels in silage from the two areas showed small differences. Milk collected after cattle had been grazing in an orchard for 3 to 4 days contained 10% more pp′-DDT and 2-, 3-, 7- and 15-fold morepp′-DDE, pp′-TDE and heptachlor epoxide, gamma-BHC and pp′-TDE olefin [1-chloro-2,2-bis(p-chlorophenyl)ethylene], respectively, than did the samples collected one day before the cattle grazed in the orchard.     

Considering degradation kinetics of pesticides in plant uptake models: proof of concept for potato

BACKGROUND

Degradation kinetics of pesticides in plants are crucial for modeling mechanism-based pesticide residual concentrations. However, due to complex open-field conditions that involve multiple pesticide plant uptake and elimination processes, it is difficult to directly measure degradation kinetics of pesticides in plants. To address this limitation, we proposed a modeling approach for estimating degradation rate constants of pesticides in plants, using potato as a model crop. An operational tool was developed to backward-estimate degradation rate constants, and three pesticides were selected to perform example simulations.

RESULTS

The simulation results of thiamethoxam indicated that the growth dynamics of the potato had a significant impact on the degradation kinetic estimates when the pesticide was applied during the early growth stage, as the size of the potato determined the uptake and elimination kinetics via diffusion. Using mepiquat, we demonstrated that geographical variations in weather conditions and soil properties led to significant differences in the dissipation kinetics in both potato plants and soil, which propagated the variability of the degradation rate constant. Simulation results of chlorpyrifos differed between two reported field studies, which is due to the effect of the vertical distribution of the residue concentration in the soil, which is not considered in the majority of recent studies.

CONCLUSIONS

Our proposed approach is adaptable to plant growth dynamics, preharvest intervals, and multiple pesticide application events. In future research, it is expected that the proposed method will enable region-specific inputs to improve the estimation of the degradation kinetics of pesticides in plants. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.     

Comparative effects of lindane and deltamethrin on mortality, growth, and cellulase activity in earthworms (Eisenia fetida)

Laboratory tests were conducted to compare the effects of various concentrations of lindane and deltamethrin on mature earthworms (Eisenia fetida) cultured in artificial soil during typical acute (14d) and subchronic (42d) exposure periods. The effects of the two pesticides on earthworm mortality, growth inhibition, and cellulase activity were determined for different exposure durations. The toxicity order for earthworm mortality from the 14-day exposure was lindane > deltamethrin, with median lethal concentrations (LC₅₀) of 162.1 and 432.9 mg kg⁻¹, respectively. Earthworms exposed to deltamethrin showed dose-dependent toxic effects on growth and cellulase activity only from the acute exposures, whereas lindane’s effects on these activities were seen correlated with both the acute and subchronic doses. Also, changes in biomass and cellulase activity during the subchronic exposure period appear to be a more sensitive parameter than the LC₅₀ value in assessing pesticidal injury.     

In vitro inhibition of the carbonic anhydrase from saanen goat (Capra hircus) with pesticides

This study was conducted to determine the in vitro effects of four commonly used pesticides (Nuarimol™, Fenarimol™, Parathion-methyl™ and 2,4-D™) on erythrocyte carbonic anhydrase (CA) activity from Saanen goats (SG). The enzyme was 262.57-fold purified by affinity chromatography and the purity was confirmed by SDS-PAGE. Inhibitory effect of the pesticides on the purified enzyme was determined using the CO₂-hydratase activity method. IC₅₀ values of the pesticides that caused inhibition were determined by means of activity percentage diagrams. The concentrations of Nuarimol™, Fenarimol™, and 2,4-D™ that inhibited 50% of the enzymatic activity were 0.352, 0.924 and 2.04 mM, respectively. Conversely, the enzyme activity was increased by parathion-methyl.     

Synthesis and antifungal activity of the proposed structure of a volatile compound isolated from the edible mushroom Hypsizygus marmoreus

We synthesized the proposed structure of an antifungal compound detected in the culture broth of the edible mushroom Hypsizygus marmoreus. Using the Evans aldol and Abiko–Masamune aldol reactions as the key steps, we synthesized all of the stereoisomers of the compound with high stereoselectivity. The GC retention times and the fragmentation patterns in the mass spectra of the synthesized isomers did not match those of the natural product. Therefore, this result may imply that it is necessary to reisolate the natural product and reconsider its structure. All of the synthesized isomers were found to exhibit antifungal activity against the phytopathogenic fungus Alternaria brassicicola. Due to their simple structures, the obtained isomers could be lead compounds for new pesticides.     

Comparative fungitoxicity of the insecticide permethrin and ten degradation products

The toxic effects of permethrin and ten of its degradation products on the growth of ten fungi were determined. Permethrin was relativelynon-toxic, with an EC₅₀ of > 100 mg litre^?1 but six of the degradation products were significantly (P= 0.05) more inhibitory. The ester hydrolysis products, 3-phenoxybenzyl alcohol and 3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid, had EC₅₀ values ranging from 8 to > 100 and 20 to > 50 mg litre^?1, respectively. Other degradation products that were more toxic than permethrin included 3-phenoxybenzaldehyde and 3-phenoxybenzoic acid, with EC₅₀ values as low as < 1 mg lite^?1. Hydroxylated and substituted-benzene metabolites were non-toxic. Combinations of selected test compounds yielded both synergistic, antagonistic and additive interaction responses, depending upon the test system employed.     

Action of pesticides on earthworms. Part I: The toxicity of cholinesterase-inhibiting insecticides to earthworms as evaluated by laboratory tests

The action of seven cholinesterase-inhibiting pesticides [aldicarb, carbaryl, carbofuran, oxamyl, paraoxon (diethyl 4-nitrophenyl phosphate) parathion and trichloronate], the organochlorine insecticide, gamma-HCH, and the nematicide potassium N-hydroxymethyl-N-methyl(dithiocarbamate) (PHMD) on four earthworm species was investigated by laboratory toxicity tests. Eisenia foetida was the most tolerant species to the pesticides tested. Aldicarb was the most toxic pesticide to this species, causing severe dehydration prior to death or at sublethal concentrations. Aldicarb was also toxic to the other species (Allolobophora caliginosa, A. chlorotica and Lumbricus rubellus), while oxamyl, the other oxime carbamate, was not toxic to any of them. Carbaryl and carbofuran at low concentrations were lethal to A. caliginosa, A. chlorotica and L. rubellus, but E. foetida could tolerate high concentrations without dying, although low concentrations severely affected its ability to work the soil or to disappear from the soil surface. Paraoxon, parathion, trichloronate and gamma-HCH were moderately toxic with low lethal effect to all species. The ability to work the soil was moderately affected by parathion, trichloronate and gamma-HCH. PHMD was toxic to all the species. The lethal and non-lethal effects of the pesticides are discussed in relation to their possible biochemical mode of action in earthworms, and the data are compared with published information from field trials.     

Influence of pesticides and application methods on pest and predatory arthropods associated with cotton

Incidence of sucking pests was studied in a transgenic (Bt) and non-transgenic cotton (non-Bt) agro ecosystem in 2008 and 2009. Simultaneously, the influence of different pesticides applied in two different methods on sucking pests and generalist predators was investigated on transgenic cotton. In stem application, the insecticides solutions prepared were painted directly on the middle portion of the plant stem but in foliar application the recommended dosages of the insecticides were sprayed on the cotton plant. The transgenic and non-transgenic cotton did not differ significantly in the population of sucking pests. The different pesticides when applied by foliar sprays reduced significantly more sucking pests than stem application. Among the different insecticides used, imidacloprid caused the maximum reduction of the leaf hopper population, acetamiprid caused the maximum whitefly reduction, and clothianidin caused the maximum thrips reduction under foliar application. Via stem application, acetamiprid and thiomethoxam were found better in suppression of the sucking pests?? population, but the population of predators was significantly less disrupted by the stem application method. The foliar application was in general more effective; stem application may be more applicable early in the season when its efficacy was higher and when foliar sprays were particularly destructive to beneficial pests. In foliar application, all the systemic neonicotinoids like imidacloprid, clothianidin, admire, thiamethoxam and acetamiprid were found highly toxic to natural enemies in comparison with spirotetramat, buprofezin and fipronil.