Effects Of Different Pesticides Research Articles

Preparation and indoor virulence determination of a temperature-sensitive insecticide against Zeugodacus cucurbitae (Coquillett).

Zeugodacus cucurbitae (Coquillett) is an important fruit and vegetable pest, especially in high-temperature seasons. In our previous research, we developed a temperature-sensitive sustained-release attractant for Z. cucurbitae, that not only can control the release rate of cuelure according to the temperature change, but also shows an excellent trapping effect on Z. cucurbitae. To further enhance the killing effect of the temperature-sensitive attractant on Z. cucurbitae, this study proposed using it in combination with an insecticide to prepare a temperature-sensitive insecticide for Z. cucurbitae. Based on the controlled release technology of pesticides, a temperature-sensitive Z. cucurbitae insecticide was developed by using PNIPAM gel as a temperature-sensitive switch to carry both cuelure and insecticide at the same time. In addition, the lethal effect of different pesticides on Z. cucurbitae were tested by indoor toxicity test, and the best pesticide combination was screened out. The temperature-sensitive insecticide prepared in this study not only had excellent thermal response and controlled release ability, but also enhanced its toxicological effects on Z. cucurbitae because it contained insecticides. Among them, combining thiamethoxam and clothianidin with the temperature-sensitive attractants was the most effective, and their lethality reached more than 97% against Z. cucurbitae. This study is not only of great practical significance for the monitoring and controlling Z. cucurbitae, but also provides theoretical basis and reference value for the combination of temperature-sensitive attractant and insecticide.

A review on effect of different pesticides on earthworm

This review seeks to raise awareness of the value of earthworms in sustainable agriculture as well as the impact of pesticides on their activity. Enhancing agricultural sustainability requires a high level of soil biodiversity. The immense diversity of soil organisms allows for the best possible utilisation of the resources found in the varied habitats at different resolution levels. By turning organic waste and biodegradable material into nutrient-rich vermicast, earthworms play a significant role in the growth and upkeep of the soil's nutritional value. They go under the name of ecological engineers as well. Earthworms are the primary agents of the process, modifying the microbial activity significantly by splintering the substrate and aerating the environment, even though microbes biochemically decompose organic materials. The biodiversity of invertebrates, particularly earthworms, has been negatively impacted by the widespread use of pesticides. Although they are impacted by intensive practices like pesticide usage, earthworms play a vital role in many ecosystem functions that promote the sustainability of agrosystems. Not only do pesticides rank among the most expensive and widely used soil toxicants, but they also directly impact soil structure through supplementing and indirectly affect it through loss of biodiversity and serious injury to non-target organisms like earthworms.

Dietary risk assessment of pesticide residues in cowpeas from Hainan province of China

This study aims to provide insights into the current status of pesticide residue contamination in Hainan province and to develop food safety regulations for controlling the excessive use of pesticides on cowpea. First, to assess the dietary exposure risks of pesticide residues in Hainan cowpea, more than 340 pesticides in 80 different fresh cowpea samples were investigated by HPLC-Q-TOF/MS/MS. Further, to indicate the health hazards of pesticide residues on consumers, the index of food safety (IFS) and risk coefficient (R) that stand for cumulative and simultaneous effects of different pesticides were calculated. A total of 56 kinds of pesticides were found in all 80 cowpea samples, and the positive rate was as high as 71 % in all samples. The results showed that the detectable rate of pesticide residues in cowpea samples were 100 % (80/80), and over 56 pesticides were detected to exceed the detection limits. In terms of IFS (<1), the safety risk of Hainan cowpeas is acceptable, but the R values of carbendazim and other 11 kinds of pesticide residues is much higher than safety level (R>1.5). These findings indicate a potential high risk of pesticide residues in Hainan cowpea, which reflect the importance of continuous monitoring and daily supervision of cowpea in Hainan.

Effects of electrolyzed water‐ultrasound treatment on pesticide removal in fresh‐cut potatoes with different cutting methods

AbstractElectrolyzed water (EW) and ultrasound (US) treatment are emerging effective means of reducing pesticides in fresh‐cut vegetables. However, their synergetic efficacy of degrading pesticides in fresh‐cut potatoes has not yet been revealed. Therefore, in this study, the effects of the combination of EW and US treatment on the removal of pesticides (chlorpyrifos, phorate, chlorothalonil, and procymidone) in fresh‐cut potato silks, strips, slices, and dices were investigated. Acidic electrolyzed water (AcEW) was selected as the optimum washing solution for pesticide removal on fresh‐cut potatoes. For the same type of fresh‐cut potato, the AcEW treatment with different sample‐to‐washing solution ratios showed no significant difference in the removal effect of different pesticides. The combined application of AcEW and US could efficiently reduce pesticides for different fresh‐cut potatoes. Furthermore, the optimal effects obtained varied greatly within the range of ultrasonic power 200–400 W and washing time 10–20 min. These results indicated that combining AcEW with US could serve as a promising method for pesticide reduction in fresh‐cut potatoes under respective appropriate process parameters.Practical ApplicationsPotato silks, strips, slices, and dices are the most common application form of fresh‐cut potatoes in Chinese dishes. Electrolyzed water (EW) and ultrasound (US) treatment have recently been used in reducing pesticides on fresh‐cut vegetables. However, their synergetic efficacy of degrading pesticides in fresh‐cut potatoes has not yet been revealed. This research provides a simple and novel method for pesticide removal on fresh‐cut potatoes. These steps combine Acidic electrolyzed water (AcEW) and US treatments to explore and improve the process parameters (sample‐to‐washing solution ratios, ultrasonic power, and washing time) of degrading pesticides for different fresh‐cut potatoes, including potato silks, strips, slices, and dices. Besides, the effect mechanism of different treatments on the degradation of pesticide residues was also discussed. The novel cleaning technology is expected to be popularized in vegetable processing plants.

Pesticide effects on soil fauna communities—A meta‐analysis

Abstract Soil invertebrate communities represent a significant fraction of global biodiversity and play crucial roles in ecosystems. A number of human activities threaten soil communities, in particular intensive agricultural practices such as pesticide use. However, there is currently no quantitative synthesis of the impacts of pesticides on soil fauna communities. Here, using a meta‐analysis of 54 studies and 294 observations, we quantify pesticide effects on the abundance, biomass, richness and diversity of natural soil fauna communities across a wide range of environmental contexts. We also identify scenarios with the most detrimental effects on soil fauna communities by analysing the effects of different pesticides (herbicides, fungicides, insecticides, broad‐spectrum substances and multiple substances), different application rates and temporal extents (short‐ or long‐term), as well as the response of different functional groups of soil animals (body size categories, presence of exoskeleton). Pesticides overall decreased the abundance and diversity of soil fauna communities across studies (Grand mean effect size (Hedge's g) = −0.30 +/− 0.16) and had stronger effects on soil fauna diversity than abundance. The most detrimental scenarios involved multiple substances, broad‐spectrum substances and insecticides, which significantly decreased soil fauna diversity even at recommended rates. We found no evidence that pesticide effects dampen over time, as short‐term and long‐term studies exhibited similar mean effect sizes. Policy implications: Our study highlights that pesticide use has significant detrimental non‐target effects on soil biodiversity, eroding a substantial part of global biodiversity and threatening ecosystem health. This provides crucial evidence supporting recent policies, such as the European Green Deal, that aim to reduce pesticide use in agriculture to conserve biodiversity. The detrimental effects of multiple substances revealed here are particularly concerning because realistic pesticide use often combines several substances targeting different pests and diseases over the crop season. We suggest that future guidelines for pesticide registration, restrictions and banning should rely on data able to fully capture the long‐term consequences of multiple substances for multiple non‐target species in realistic conditions.

Analysis of effects of different pesticides on mammalian system

Analysis of effects of different pesticides on mammalian system

Use of biosensors for rapid and sensitive detection of pesticides in food samples for food safety chemical risk assessment.

The utility of pesticides in the agricultural field is unquestionable, but at the same time pesticide use presents serious hazards to the environment and the human health. For that reason, detection of pesticides and their biotransformation products in food is of utmost importance. According to previous studies, esterase-based biosensors have been proposed as a viable and efficient solution for the detection of organophosphate pesticides. In this project, a double mutant of the thermostable esterase-2 (EST2) from Alicyclobacillus acidocaldarius was studied as a potential biosensor, for its ability to detect residual amounts of pesticides. Initial characterisation of the enzyme was performed, that included determination of optimal pH, thermophilicity, as well as kinetic analysis. Subsequently, the enzyme was studied by enzymatic activity assays with and without the presence of various organophosphate compounds. The effect of the organophosphates on the enzymatic activity was measured and complete inhibition of the enzyme was observed after incubation with paraoxon. These experiments were followed by an additional method involving labelling of the enzyme with a fluorescent probe. In this case, the effect of different pesticides on the EST2 enzyme was monitored by measuring the fluorescence quenching upon addition to the enzyme. Fourteen compounds were screened with this method and significant fluorescence quenching was observed in the presence of paraoxon and methyl-paraoxon when used in equimolar amounts with the enzyme in the range of nanomolar. This biosensor has been also used to test the presence of pesticides in real food samples, like fruits and juices. This research represents a starting point to develop effective fluorescence-based biosensors aiming at the screening of mutants with different pesticide selectivity profiles. The use of this enzyme-based biosensor can have applications in the field of food traceability as well as environmental monitoring, to control the presence of toxic chemicals, in particular organophosphate pesticides.

A recurring error in evaluating the effects of different pesticides, pollutants and fertilizers with a zero level

BackgroundThe Quenouille-Addelman solution has been proposed to properly analyze linear models with a crossed or factorial arrangement of treatments that includes a qualitative/categorical and a quantitative factor with a zero level, a situation particularly prevalent in ecotoxicological studies. However, a review of the recent literature reveals that this solution isn’t used, perhaps due to a lack of recognition that zero-level factors can produce incomplete factorial arrangements.ResultsUsing practical examples, I demonstrate that the conclusions of a study can be substantially altered if the Quenouille-Addelman solution is not used when warranted.ConclusionsSuspecting that the lack of a detailed method may have contributed to the underutilization of the solution, I describe how to apply the solution using current statistical software packages and discuss how the solution can be adapted to address some experimental situations not previously considered.

Effects of Different Pesticides on the Brewing of Wine Investigated by GC-MS-Based Metabolomics.

The application of pesticides is critical during the growth of high-quality grape for wine making. However, pesticide residues have significant influence on the wine flavor. In this study, gas chromatography-mass spectrometry (GC-MS) was performed and the obtained datasets were analyzed with multivariate statistical methods to investigate changes in flavor substances in wine during fermentation. The principal component analysis (PCA) score plot showed significant differences in the metabolites of wine treated with various pesticides. In trials using five pesticides (hexaconazole, difenoconazole, flutriafol, tebuconazole, and propiconazole), more than 86 metabolites were changed. Most of these metabolites were natural flavor compounds, like carbohydrates, amino acids, and short-chain fatty acids and their derivatives, which essentially define the appearance, aroma, flavor, and taste of the wine. Moreover, the five pesticides added to grape pulp exhibited different effects on the metabolic pathways, involving mainly alanine, aspartate and glutamate metabolism, butanoate metabolism, arginine, and proline metabolism. The results of this study will provide new insight into the potential impact of pesticide residues on the metabolites and sensory profile of wine during fermentation.

Effects of Different Pesticides on the Biological Control Agent, Habrobracon hebetor Say (Hymenoptera: Braconidae): A Review

I reviewed effects of different pesticides used against target insect of Habrobracon hebetor Say (an idiobiont and gregarious ectoparasitoid wasp), on the demography and functional response of this important biocontrol agent in Iran. For demographic studies, the young wasps of H. hebetor (under 24h old) were exposed to LC30 of each pesticide for 24h and then their desired features are investigated. About the functional response, sixty mated females of H. hebetor were treated by LC30 of selected pesticides for 24h. Then, among them six wasps were selected and introduced to different densities of host larvae for 24h. In conclusion, result of review confirmed that botanical and insect growth regulator (IGRs) pesticide due to the lowest negative effects on H. hebetor were compatible compared with the other pesticides for their successful combination in integrated pest management (IPM) designs.

Relationship between Prenatal or Postnatal Exposure to Pesticides and Obesity: A Systematic Review.

In recent years, the worldwide prevalence of overweight and obesity among adults and children has dramatically increased. The conventional model regarding the onset of obesity is based on an imbalance between energy intake and expenditure. However, other possible environmental factors involved, such as the exposure to chemicals like pesticides, cannot be discarded. These compounds could act as endocrine-disrupting chemicals (EDC) that may interfere with hormone activity related to several mechanisms involved in body weight control. The main objective of this study was to systematically review the data provided in the scientific literature for a possible association between prenatal and postnatal exposure to pesticides and obesity in offspring. A total of 25 human and 9 animal studies were analyzed. The prenatal, perinatal, and postnatal exposure to organophosphate, organochlorine, pyrethroid, neonicotinoid, and carbamate, as well as a combined pesticide exposure was reviewed. This systematic review reveals that the effects of pesticide exposure on body weight are mostly inconclusive, finding conflicting results in both humans and experimental animals. The outcomes reviewed are dependent on many factors, including dosage and route of administration, species, sex, and treatment duration. More research is needed to effectively evaluate the impact of the combined effects of different pesticides on human health.

Investigating the Wettability of Rapeseed Leaves

HighlightsContact angles of spray droplets were positively correlated with their surface tension.Wettability of rape leaves was generally poor for most pesticides.Surface structure and free energy determine the hydrophobicity of rape leaves.The size of the spray droplets had no significant influence on rape leaf wettability.Abstract. In order to improve the deposition and adherence of spray droplets on leaf surfaces, the wettability of rapeseed leaves was investigated. We explored the effect of different pesticides and test surfaces on droplet contact angles, and analyzed the effects of leaf surface properties, droplet sizes and the addition of organosilicone adjuvant on wettability. The results indicated that contact angles of different liquids were positively correlated with their surface tension for rapeseed leaves. The wettability of rapeseed leaves was generally poor using different pesticides, but was highest for a fungicide mixture of difenoconazole and propiconazole. The hydrophobicity of rapeseed leaves is largely determined by the complex microstructure and the low surface free energy of the leaves. The size of the spray droplets had no significant influence on the wettability. Moreover, the addition of an organosilicone adjuvant significantly reduced the surface tension of all spray droplets, with the best result for a 50% procymidone solution. In conclusion, the factors affecting rapeseed leaf surface wettability should be considered comprehensively before selecting the appropriate pesticide, so as to improve its utilization rates. Keywords: Contact angle, Leaf surface, Pesticide application, Spray droplet.

A prospective cohort study of school-going children investigating reproductive and neurobehavioral health effects due to environmental pesticide exposure in the Western Cape, South Africa: study protocol

BackgroundResearch on reproductive health effects on children from low-level, long-term exposure to pesticides currently used in the agricultural industry is limited and those on neurobehavioral effects have produced conflicting evidence. We aim at investigating the association between pesticide exposure on the reproductive health and neurobehavior of children in South Africa, by including potential relevant co-exposures from the use of electronic media and maternal alcohol consumption.MethodsThe design entails a prospective cohort study with a follow-up duration of 2 years starting in 2017, including 1000 school going children between the ages of 9 to 16 years old. Children are enrolled with equal distribution in sex and residence on farms and non-farms in three different agricultural areas (mainly apple, table grapes and wheat farming systems) in the Western Cape, South Africa. The neurobehavior primary health outcome of cognitive functioning was measured through the iPad-based CAmbridge Neuropsychological Test Automated Battery (CANTAB) including domains for attention, memory, and processing speed. The reproductive health outcomes include testicular size in boys and breast size in girls assessed in a physical examination, and blood samples to detect hormone levels and anthropometric measurements. Information on pesticide exposure, co-exposures and relevant confounders are obtained through structured questionnaire interviews with the children and their guardians. Environmental occurrence of pesticides will be determined while using a structured interview with farm owners and review of spraying records and collection of passive water and air samples in all three areas. Pesticide metabolites will be analysed in urine and hair samples collected from the study subjects every 4 months starting at baseline.DiscussionThe inclusion of three different agricultural areas will yield a wide range of pesticide exposure situations. The prospective longitudinal design is a further strength of this study to evaluate the reproductive and neurobehavioural effects of different pesticides on children. This research will inform relevant policies and regulatory bodies to improve the health, safety and learning environments for children and families in agricultural settings.

Influence of Different Pesticides on Chemical, Biochemical and Yield Parameters of Brinjal (Solanum melongena L.)

Pesticides have become an essential part of agricultural and horticultural practices. There is continuous development of new pesticides to address specific requirement (insect /pest control). New pesticides with specific mode of action, combination to two or more pesticides for enhanced bio-efficacy, new innovation in the field of slow and sustained delivery of chemical are making the pesticides influence positively in growth and development of plant. In present investigation, all four pesticides used at recommended dosage suggested by agricultural experts. These pesticides are most proffered by farmers to control fruit and shoot borer on brinjal. A study on the influence of pesticides persistence on biochemical and yield parameters of brinjal was conducted during kharif and rabi 2013-14 and 14-15 with the objective of physiological responses of different varieties of brinjal (Malapur local-V1, Kalpataru-V2, Manjula-V3, Manjari-V4) sprayed with four different pesticides (thiodicarb-P1, spinosad-P2, profenophos-P3 and chlorantranilliprole-P4). The P0 treatment considered as a non-sprayed control. The experiment was laid out in factorial randomized block design with three replications. The pesticides sprayed at recommended dose (thiodicarb 75WP@1 g-1l, spinosad 45SC@0.1 ml-1l-1l profenophos 50EC@2 ml-1l and chlorantraniliprole 20 SC@0.5 ml-1l) suggested by agricultural experts. Results indicated highly significant differences between the varieties and pesticides treatments at all the stages and in both the seasons. The interaction between the varieties and pesticide treatments was also significant at all the stages. The values of chlorophyll content successive increased from 70 to 90 DAT and decreases from 115 and 125 DAT in both the seasons. The magnesium content in fruits was recorded highest at 90 DAT followed by 80 DAT irrespective of varieties and pesticides. It is clear from the data that Manjar treated with Profenophos indicated maximum magnesium content recorded followed by Manjari treated with chlorantraniliprole compared to other interaction. Total marketable yield noticed maximum in Manjari followed by Manjula and Kalpataru while least was in Malapur local. The profenophos treatments observed with highest marketable yield over the chlorantraniliprole. Spinosad and thiodicarb treatments. Among all the interaction, V4P3 (6.12 kg plant-1) recorded maximum marketable fruit yield and minimum was in untreated Malapur local varity of brinjal interaction. Different varieties of brinjal used in investigation to assess its behavior in regard to find its optimum tolerance limit for healthy growth for maximizing quality production and to minimize the risk of stress created by pesticides in the brinjal during different growing seasons. Lot of work done on plant protection by different agrochemical/pesticides, but this study helpful to know the effects of different pesticides on plant growth and metabolism.

Development of Flow Injection Spectrophotometric Method for 1-Napthylthiourea Using Sodium Nitrite and Sulphanilic Acid Diazotization Reaction

A simple spectrophotometric method in conjunction with flow injection analysis is developed for the quantitative analysis of 1-napthylthiourea (ANTU). The reaction is based on the alkaline hydrolysis of ANTU to 1-naphthylamine at 30°C, coupled with diazotized sulphanilic acid resulting in 4-(sulphophenylazo)-1-naphthylamine which is monitored at 495 nm. The limit of detection (S/N = 3) is 0.01 mg/L with a sampling throughput of 45/h. The method is linear over the range of 0.05–120 mg/L (R2=0.9995,n=7), with calibration equation y = 0.031x−0.018 (y = absorbance; x = mg/L) and relative standard deviation (n=3) 1.8–3.6%. Experimental variables are optimised, and the interfering effects of different pesticides, organic compounds, cations, and anions at environmentally relevant concentrations are investigated. The analysis of ANTU in spiked water samples is extracted with solid phase procedure using disposable Sep-Pak C18 cartridges, and the recovery was 93 ± 1.9–110 ± 3.0%. The results of the proposed method are compared with the HPLC method by applying the F-test and paired Student t-test at 95% confidence level.

Developmental Exposure to Pesticides Alters Motor Activity and Coordination in Rats: Sex Differences and Underlying Mechanisms.

It has been proposed that developmental exposure to pesticides contributes to increasing prevalence of neurodevelopmental disorders in children, such as attention deficit with hyperactivity (ADHD) and to alterations in coordination skills. However, the mechanisms involved in these alterations remain unclear. We analyzed the effects on spontaneous motor activity and motor coordination of developmental exposure to a representative pesticide of each one of the four main chemical families: organophosphates (chlorpyrifos), carbamates (carbaryl), organochlorines (endosulfan), and pyrethroids (cypermethrin). Pesticides were administered once a day orally, in a sweet jelly, from gestational day 7 to post natal day 21. Spontaneous motor activity was assessed by an actimeter and motor coordination using the rotarod, when rats were adults. The effects were analyzed separately in males and females. Extracellular GABA in cerebellum and NMDA receptor subunits in hippocampus were assessed as possible underlying mechanisms of motor alterations. Motor coordination was impaired by developmental exposure to endosulfan, cypermethrin, and chlorpyrifos in females but not in males. The effect of endosulfan and cypermethrin would be due to increased extracellular GABA in cerebellum, which remains unaltered in male rats. Chlorpyrifos increased motor activity in males and females. Cypermethrin decreased motor activity mainly in males. In male rats, but not in females, expression of the NR2B subunit of NMDA receptor in hippocampus correlated with motor activity. These results show sex-specific effects of different pesticides on motor activity and coordination, associated with neurotransmission alterations. These data contribute to better understand the relationship between developmental exposure to the main pesticide families and motor disorders in children.

Interaction of almond cystatin with pesticides: Structural and functional analysis.

Pesticides are chemical substances that eliminate or control a variety of agricultural pests that damage crops and livestock. They not only affect the targeted pests but also affect the nontargeted systems, raising more concerns for their effect on both plant and animal systems. Cystatins (cysteine protease inhibitor) are ubiquitously present in all living cells and show a variety of important physiological functions. The present study shows the effect of different pesticides (pendimethalin, methoxyfenozide, and CuII hydroxide) on purified almond cystatin. Almond cystatin showed concentration-dependent loss in papain inhibitory activity on interaction with the pesticides, showing maximum loss in the presence of Cu(II) hydroxide and minimum in the case of methoxyfenozide. Native polyacrylamide gel electrophoresis showed maximum degradation of purified cystatin in the presence of Cu(II) hydroxide with insignificant effect in the presence of methoxyfenozide. Structural alterations were significant in the case of Cu(II) hydroxide and less in the case of methoxyfenozide as revealed by UV and fluorescence spectral studies. Secondary structural alterations were further conformed by circular dichroism and Fourier transform infrared spectroscopy. The α-helix content of almond cystatin decreases from 35.64% (native) to 34.83%, 30.79%, and 29.62% for methoxyfenozide-, pendimethalin-, and Cu(II) hydroxide-treated cystatin, respectively. A Fourier transform infrared study shows an amide I band shift for almond cystatin from 1649.15±0.5 to 1646.48±0.6, 1640.44±0.6, and 1635.11±0.3cm-1 for methoxyfenozide, pendimethalin, and Cu(II) hydroxide, respectively. Values obtained for different thermodynamic parameters (ΔH0 , ΔG0 , N, and ΔS0 ) by isothermal titration calorimetric experiments reveal maximum binding of almond cystatin with Cu(II) hydroxide followed by pendimethalin and little interaction with methoxyfenozide.

Fast pesticide detection inside microfluidic device with integrated optical pH, oxygen sensors and algal fluorescence

The necessities of developing fast, portable, cheap and easy to handle pesticide detection platforms are getting attention of scientific and industrial communities. Although there are some approaches to develop microchip based pesticide detection platforms, there is no compact microfluidic device for the complementary, fast, cheap, reusable and reliable analysis of different pesticides. In this work, a microfluidic device is developed for in-situ analysis of pesticide concentration detected via metabolism/photosynthesis of Chlamydomonas reinhardtii algal cells (algae) in tap water. Algae are grown in glass based microfluidic chip, which contains integrated optical pH and oxygen sensors in a portable system for on-site detection. In addition, intrinsic algal fluorescence is detected to analyze the pesticide concentration in parallel to pH and oxygen sensors with integrated fluorescence detectors. The response of the algae under the effect of different concentrations of pesticides is evaluated and complementary inhibition effects depending on the pesticide concentration are demonstrated. The three different sensors allow the determination of various pesticide concentrations in the nanomolar concentration range. The miniaturized system provides the fast quantification of pesticides in less than 10min and enables the study of toxic effects of different pesticides on Chlamydomonas reinhardtii green algae. Consequently, the microfluidic device described here provides fast and complementary detection of different pesticides with algae in a novel glass based microfluidic device with integrated optical pH, oxygen sensors and algal fluorescence.

Assessing risks of pesticides targeting lepidopteran pests in cruciferous ecosystems to eggs parasitoid, Trichogramma brassicae (Bezdenko).

Lethal and sub lethal effects of fresh and old residues of azadirachtin, spinosad, Bacillus thuringiensis var. kurstaki (Bt var. k), and deltamethrin, were evaluated at their recommended field doses against adult and immature stages of Trichogramma brassicae under in vitro conditions. The experiments were carried out at the Entomology section of Division of Crop Protection, ICAR Research Complex for NEH region, Umiam, Meghalaya, in 2012–2013. The effects of different pesticides were determined by bioassays using the residual film method, the diet contamination method, the pupal dip method and the topical application technique. The four pesticides were found harmful to adult T. brassicae after ingestion, however surface contact bioassays revealed that Bt var. k was the least toxic pesticide. Except Bt var. k, other three pesticides were found harmful also to the immature stages of T. brassicae and significantly affected parasitism potential, adult emergence, longevity of adults, and sex ratio of the progeny. Deltamethrin and azadirachtin were the most harmful, even after 15 days of application. Spinosad was found to be relatively safe to T. brassicae after 15 days of application. As Bt appeared to be the least toxic pesticide for T. brassicae, it could be used for the management of severe infestations of lepidopteran pests in cruciferous ecosystems.If essential, spinosad may be used 15 days after parasitoid release, thus minimizing the chances of parasitoid exposure.

Effects of different pesticides on virulence and mortality of some entomopathogenic nematodes

Entomopathogenic nematodes (EPNs) have been used against especially soil borne insect pests. EPNs are feasible and attractive for biological control, because of their virulence against various insect pests, host seeking ability, being usable with standard equipment, and long-term efficacy. In addition EPNs can be applied simultaneously with some pesticides. These properties make EPNs ideal biocontrol agent in integrated pest management. In the present study, effects of 4 widely used pesticides (Glyphosate, Chlorpyrifos-ethyl, Captan, Fosetyl-al) on virulence and mortality of three EPN strains (Heterorhabditis bacteriophora Alman, H. bacteriophora HbH and Steinernema carpocapsae DD-136) were examined at 24 and 48 h periods. All strains were able to infect Galleria mellonella larvae averagely above 90 % rate, after 24 and 48 h treatments with all pesticides. However, some of the pesticides showed negative impact on the viability of the strains. Especially, DD-136 and Fosetylal seemed like incompatible, as the mortality rates were significantly higher than control for both 24 and 48 h. The results of the present study showed that it may be possible to use some EPN strains with some pesticides. It is expected that the results of the study will provide useful information for future integrated pest management programs.