emamectin-benzoate and cyhalothrin

Inadequate pesticide application practices have many implications on human and environmental health. This research aimed at assessing pesticide risks on bees, non-target arthropods (NTAs) and earthworms, using PRIMET (Pesticide Risks in the Tropics to Man, Environment and Trade), a pesticide risk model, in the western highlands agro-ecological zone of Cameroon. For this purpose, information on pesticide usage stratagem (dosage, application interval and number of applications) and ecotoxicological properties (median lethal doses, persistence and no observable effect concentration) were gathered and entered into PRIMET to acquire the Predicted Exposure Concentration (PEC), No Effect Concentration (NEC) and Exposure Toxicity Ratio, ETR = PEC / NEC). The risk assessment revealed that the riskiest pesticides for earthworms were acetamiprid, glyphosate and imidacloprid with ETR values of 2963, 1667 and 419 respectively. For bees, acetamiprid, cypermethrin, emamectin benzoate, imidacloprid, and lambda-cyhalothrin were highly risky, with respective ETR values of 3252, 487, 278, 1383 and 295. The model predicted NTAs to be predominantly defenceless against cypermethrin and imidacloprid, as these compounds exhibited the topmost values of ETR of, 4.3 × 10

Topics: Agriculture; Animals; Bees; Humans; Insecticides; Male; Pesticides

Grapholita molesta is one of the most damaging pests worldwide in stone and pome fruits. Application of chemical pesticides is still the main method to control this pest, which results in resistance to several types of insecticides. Carboxylesterase (CarE) is one of the important enzymes involved in the detoxification metabolism and tolerance of xenobiotics and insecticides. However, the roles of CarEs in insecticides susceptibility of G. molesta are still unclear. In the present study, the enzyme activity of CarEs and the mRNA expression of six CarE genes were consistently elevated after treatment with three insecticides (emamectin benzoate, lambda-cyhalothrin, and chlorantraniliprole). According to spatio-temporal expression profiles, six CarE genes expressed differently in different developmental stages, and highly expressed in some detoxification metabolic organs. RNAi-mediated knockdown of these six CarE genes indicated that the susceptibility of G. molesta to all these three insecticides were obviously raised after GmCarE9, GmCarE14, GmCarE16, and GmCarE22 knockdown, respectively. Overall, these results demonstrated that GmCarE9, GmCarE14, GmCarE16, and GmCarE22 play a role in the susceptibility of G. molesta to emamectin benzoate, lambda-cyhalothrin, and chlorantraniliprole treatment. This study expands our understanding of CarEs in insects, that the same CarE gene could participate in the susceptibility to different insecticides.

Topics: Animals; Carboxylesterase; Insecticides; Larva; Moths

Helicoverpa armigera is a major devastating insect pest on a wide range of vegetables and cash crops. Insecticides are presently indispensable for its control in nearly all crops. H. armigera has acquired resistance against almost all insecticides because of the activity of detoxification enzymes used for the defensive mechanism. The current research was carried out to evaluate the activity of detoxification enzymes, i.e., acetylcholinesterase and alkaline and acid phosphatases in chlorpyrifos-, bifenthrin-, lufenuron-, lambda cyhalothrin-, and emamectin benzoate-treated larvae of H. armigera. The maximum AChE activity was recorded in emamectin benzoate-treated larval samples followed by chlorpyrifos, lufenuron, lambda cyhalothrin and bifenthrin, respectively, while the highest alkaline phosphatases' activity was recorded in emamectin and the lowest in bifenthrin-treated H. armigera. As far as acid phosphatases' activity is concerned, the highest activity was noted in lufenuron samples while the lowest in lambda cyhalothrin samples, respectively. Comparatively, activities of alkaline and acid phosphatases were higher than AChE. The elevated activities of detoxification enzymes can possibly lead to increase in resistance development against synthetic chemical insecticides.

Topics: Acetylcholinesterase; Acid Phosphatase; Alkaline Phosphatase; Animals; Chlorpyrifos; Disaccharides; Inactivation, Metabolic; Insect Proteins; Insecticide Resistance; Insecticides; Ivermectin; Larva; Moths; Nitriles; Pyrethrins

The aim of this study was to determine the insecticide residue processing factor (PF) from plums to prunes and the effect of the industrial processing of prunes residue concentrations. Our results show an increase of insecticide concentrations during plum dehydration that is explained by fruit water loss; however, the normalized insecticide residue concentration, based on plum dry weights to compensate dehydration, was reduced. The water washing and tenderizing of prunes produced insecticide residue reductions of 22.9 ± 4.5% and 21.9 ± 4.2%, respectively. PF were: 1.157, 1.872, 1.316, 0.192, 2.198, 0.775 and 0.156 for buprofezin, l-cyhalothrin, spirodiclofen, indoxacarb, acetamiprid, imidacloprid and emamectin benzoate, respectively, being directly related to water solubility, aqueous hydrolysis and degradation point and inversely related to molecular mass and melting point. In plums for the dehydrated agroindustry the final product is prunes, therefore, it is crucial to consider the PF to determine the specific preharvest interval for this important agroindustry.

Topics: Fruit; Gas Chromatography-Mass Spectrometry; Ivermectin; Neonicotinoids; Nitriles; Nitro Compounds; Oxazines; Oxidation-Reduction; Pesticide Residues; Prunus domestica; Pyrethrins; Solid Phase Extraction

Pesticides are highly toxic substances. Their toxicity may not be absolutely specific to the target organisms but can adversely affect different processes in the non-target host plants. In the present study, the effect of over application of four commonly used pesticides (emamectin benzoate, alpha-cypermethrin, lambda-cyhalothrin and imidacloprid) was evaluated on the germination, seedling vigor and photosynthetic pigments in tomato. The obtained results revealed that seed germination was decreased by the pesticides and this effect was more prominent at early stages of exposure. All the tested pesticides reduced the growth of tomato when applied in higher concentration than the recommended dose, but at lower doses the pesticides had some stimulatory effects on growth as compared to the control. A similar effect of pesticides was observed on the photosynthetic pigments, i.e. a decrease in pigments concentrations was caused at higher doses but an increase was observed at lower doses of pesticides. The calculation of EC50 values for different parameters revealed the lowest EC50 values for emamectin (ranged as 51-181 mg/L) followed by alpha-cypermethrin (191.74-374.39), lambda-cyhalothrin (102.43-354.28) and imidacloprid (430.29-1979.66 mg/L). A comparison of the obtained EC50 values for different parameters of tomato with the recommended doses revealed that over application of these pesticides can be harmful to tomato crop. In a few cases these pesticides were found toxic even at the recommended doses. However, a field based study in this regard should be conducted to further verify these results.

Topics: Disaccharides; Germination; Imidazoles; Insecticides; Ivermectin; Neonicotinoids; Nitriles; Nitro Compounds; Pakistan; Photosynthesis; Pyrethrins; Seedlings; Solanum lycopersicum

At present, chemical-based tick control strategies are still the most efficient and widely used methods in control of ticks and tick-borne diseases. In this study, the efficacies of lambda-cyhalothrin, beta-cypermethrin, emamectin benzoate, spirotetramat and hexaflumuron in vitro were evaluated against Hyalomma asiaticum, Haemaphysalis longicornis and Rhipicephalus sanguineus that are widespread and able to transmit a variety of human and animal diseases in China. The results showed that the LC (lethal concentration) 50 of lambda-cyhalothrin, beta-cypermethrin, emamectin benzoate, spirotetramat and hexaflumuron were 22.05, 107.35, 287.62, 432.25 and over 6250 mg/L to Hy. asiaticum engorged nymphs, respectively. The LC50 of lambda-cyhalothrin and beta-cypermethrin were each to 100.69 mg/L and 340.05 mg/L against Hy. asiaticum unfed adults. In addition, 50 mg/L of lambda-cyhalothrin could completely inhibit engorged females of the 3 tick species to lay eggs. These results indicate that lambda-cyhalothrin has the highest efficacy and broadest spectrum for against the 3 tick species. The present study provides some information for selecting chemical acaricides in control ticks and tick-borne-diseases, as well for preparing acaricide mixtures to improve killing efficacy, and retard the advent of tick-resistance of acaricides in China.

Topics: Acaricides; Animals; Aza Compounds; Benzamides; Female; Ivermectin; Ixodidae; Lethal Dose 50; Nitriles; Phenylurea Compounds; Pyrethrins; Rabbits; Random Allocation; Rhipicephalus sanguineus; Sheep; Spiro Compounds