Toxicity Effect of Three Insecticides on Important Pests and Predators in Tomato Plants (original) (raw)
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The present experiment was conducted to assess relative toxicity of selected insecticides against whitefly in the Entomology laboratory at College of Horticulture, Mudigere during the year 2014-2015. Among the eleven treatments, imidachloprid, thiamethoxam and cyantraniliprole were highly toxic to adults which recorded 100 per cent mortality, four days after treatment. Cyantraniliprole recorded the highest adult mortality comparatively early than imidachloprid and thiamethoxam. Fipronil 80% WG, recorded 100 percent mortality five days after treatment which was followed by emamectin benzoate 5% SG at sixth day after treatment and recorded as next best treatments under laboratory condition against whitefly. Acephate 75% SP and azadirhactin 10000 ppm recorded highest level of mortality (100%) at seventh and eighth day after treatment, respectively which was followed by triazophos 40% EC, spinosad 480% SC and buprofezin 25% SC at eleventh day after treatment. Considering the result, cyantraniliprole, thiamethoxam and imidacloprid were recommended for effective control of sucking pests in cotton ecosystem.
Journal of entomology and zoology studies, 2018
The present experiment was conducted to assess relative toxicity of selected insecticides against whitefly in the Entomology laboratory at College of Horticulture, Mudigere during the year 2014-2015. Among the eleven treatments, imidachloprid, thiamethoxam and cyantraniliprole were highly toxic to adults which recorded 100 per cent mortality, four days after treatment. Cyantraniliprole recorded the highest adult mortality comparatively early than imidachloprid and thiamethoxam. Fipronil 80% WG, recorded 100 percent mortality five days after treatment which was followed by emamectin benzoate 5% SG at sixth day after treatment and recorded as next best treatments under laboratory condition against whitefly. Acephate 75% SP and azadirhactin 10000 ppm recorded highest level of mortality (100%) at seventh and eighth day after treatment, respectively which was followed by triazophos 40% EC, spinosad 480% SC and buprofezin 25% SC at eleventh day after treatment. Considering the result, cya...
The relative residual toxicity of selected insecticides against whitefly was assessed in the Entomology laboratory at College of Horticulture, Mudigere during the year 2014-2015. The treatments viz., imidachloprid (15.70 to 22.97%), triazophos (10.43 to 21.97%), thiamethoxam (20.77 to 37.97%), cyantraniliprole (20.03 to 34.37%), azadirhactin (10.40 to 18.27%), fipronil (6.60 to 29.10%) and buprofezin (7.93 to 17.00%) showed high level of residual toxicity up to sixth day after the treatment. From eighth day after treatment, toxicity started decreasing. However, in treatments acephate and emamectin benzoate, residual toxicity started decreasing from sixth day itself. Although toxicity of spinosad (15.23%) was noticed to be high at two days after treatment, its toxicity started decreasing from fourth day itself. At sixth day after treatment, the order of residual toxicity was thiamethoxam > cyantraniliprole > fipronil > imidachloprid > triazophos > azadirhactin > buprofezin > spinosad > emamectin benzoate > acephate.
Insects
The generalist mirid predator Macrolophus basicornis may contribute to Integrated Pest Management (IPM) of Bemisia tabaci in tomato crops. It is important to know the compatibility of the chemicals used to control this pest with this promising biological control agent. Seven insecticides were tested to investigate their toxicity to the predator. For four of the products, the LC50 for adults were determined. Buprofezin, cyantraniliprole and spiromesifen did not cause lethality and were classified as harmless. Acetamiprid, bifenthrin, etofenprox + acetamiprid and pyriproxyfen + acetamiprid caused acute toxicity and were classified as harmful. LT50 for all harmful insecticides were relatively low, ranging from 1.8 to 3.2 days. Moreover, these four insecticides have low LC50, with acetamiprid (0.26 mg a.i. L−1) as the lowest, followed by bifenthrin (0.38 mg a.i. L−1), etofenprox + acetamiprid (4.80 mg a.i. L−1) and pyriproxyfen + acetamiprid (8.71 mg a.i. L−1). However, the calculated r...
Molecules
The whitefly, Bemisia tabaci, is the main pest for many field and horticultural crops, causing main and significant problems. The efficiency of imidacloprid insecticide as seed treatment and foliar spray at three rates against the whitefly, B. tabaci, was evaluated in tomato plants under field conditions; in addition, insecticide residues were determined in tomato leaves and fruits. The obtained results revealed that the seedlings produced from treated seeds with imidacloprid were the most effective treatment in decreasing whitefly stages. Reduction percentages of whitefly stages in seedlings produced from treated seeds and sprayed with ½, ¾ and 1 field rates of imidacloprid were more than that produced from untreated seeds. Tomato fruit yield in seedlings produced from treated seeds and sprayed with one recommended rate of imidacloprid was more than that of untreated seeds. The residues of imidacloprid in leaves and fruits in seedlings produced from treated seeds and sprayed with f...
Residues of some rational insecticides (etofenprox, imidacloprid and spirotetramat) in tomatoes fruits were determined after three applications. The results showed that the residues of tested insecticides in zero time (after one hour of insecticides treatment) were the maximum. After the first application the residues of these insecticides were 2.62, 0.91 and 0.95 mg/kg for imidacloprid, spirotetramat and etofenprox, respectively. The corresponding results after the second and third applications were 3.14, 0.95 and 0.96; 3.42, 1.06 and 0.86 mg/kg, respectively. After one week intervals the insecticides residues were decreased to 0.089, 0 and 0; 0.009, 0 and 0; 0.18, 0.04 and 0.05 mg/kg, respectively. The dissipation rate after the third application was 94.7, 92.2 and 94.2% for imidacloprid, spirotetramat and etofenprox, respectively. The results showed that imidacloprid has a minimum preharvest interval (PHI) followed by spirotetramat and etofenprox. The Pre-Harvest Interval (PHI) was 3.8, 5.8 and 6.8 days, respectively. The results showed also, imidacloprid was the most toxic against sweet potato whitefly adults followed by etofenprox and spirotetramat. The reduction percent of whitefly adults was 98.7, 93.7 and 30%, respectively. The results recommended that using of imidacloprid in sweet potato whitefly control was effective and safely.
Journal of Entomological Society of Iran, 2021
Tomato leaf miner (TLM), Tuta absoluta (Meyrick), is a destructive insect pest in greenhouses and fields on tomato plants. In this study, the efficacy of seven insecticides: spinosad (Laser ®), chlorantraniliprole (Coragen ®), indoxacarb (Steward ®), abamectin (Vertimec ®), metaflumizone (Alverde ®), azadirachtin (NeemAzal ®), and Bacillus thuringiensis was evaluated against T. absoluta during 30 days from spraying. Tomato plants were sprayed by half and a quarter of the recommended field concentrations of the insecticides. Thirty 2 nd instar larvae were placed on the treated plants, 2, 4, 7, 10, 13, 17, 22, 26, and 30 days after treatment, and mortality was recorded 48 hours later. The results showed that spinosad and chlorantraniliprole in the half of the field recommended concentration caused maximum efficacy on T. absoluta larvae, 100 and 80 % mortality at the end of 30 days, respectively. On the other hand, indoxacarb caused 57 % mortality on the 22 nd day after exposure to the quarter of the field recommended concentration. In the quarter field-recommended concentration, abamectin and metaflumizone also had moderate mortality (52 and 54 % on the 10 th day). The application of these three compounds can be considered suitable for preventing an increasing pest population from reaching the economic injury level. Bacillus thuringiensis var. kurstaki and azadirachtin insecticides had slight mortality and short persistence on this pest. Experts and farmers can select the appropriate compounds to control this pest based on the pest population status according to the obtained results.