• Korean journal of applied entomology
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• v.28 no.1
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• pp.32-36
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• 1989

The joint toxic action of mixtures of cypermethrin or pirimicarb with one of other insecticides (acephate, cypermethrin, demeton-S-methyl and pirimicarb) on the cypermethrin or picimicarb-selected green peach aphid (Myzus persicae Sulzer)was investigated. The responses depended on the choice and ratios of insecticide combination. In the cypermethrin-selected strain bioas-say, mixtures of test insecticides showed no synergistic effect. On the other hand, the maxi-mum synergistic effects for the pirimicarb-selected strain were obtained at the 8 : 2 ratio of pirimicarb and demeton-S-methyl exhibited antagonistic effect.

• Korean journal of applied entomology
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• v.26 no.3 s.72
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• pp.159-163
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• 1987

The toxicity of the mixture at 1 to 1 ratio among the insecticides, BPMC, carbofuran, diazinon and monocrotophos to the brown planthopper (BPH), Nilaparvata lugens and green leafhopper (GLH), Nephotettix virescens were tested and compared to their toxicities of individual insecticides. Among the mixtures, carbofuran combinations with BPMC and diazinon showed synergistic effect in toxicity to BPH. There was also synergistic action in toxicity with mixture of BPMC plus monocrotophos to GLH. Other combinations were independent in toxic action to both insects.

• Korean journal of applied entomology
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• v.31 no.3
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• pp.314-327
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• 1992

Insecticide resistance is a serious is a serious threat to IPM, resulting in various adverse effects not to mention the loss of yield in agriculture. One approach to counter the problem is the disruption of resistance mechanisms. This can be achieved by (1) compounds which show a negative correlation with resistance at the site of action, (2) specific metabolic inhibitors which serve as synergists, or (3) a certain combination of two insecticides producing a joint action. This approach, however, requires certain precautions for the side effects may cause an increase in toxicity to mammals. Owing to the recent advances in theoretical studies on resistance management employing computer simulation and mathematical models, a few principles to reduce the risk of development of resistance have been clarified. They are helpful in designing operational strategies with regard to, for instance, insecticide doses to be applied, mode of application, and choice and nature of the insecticide(s) to be used. For restoration of insecticide susceptibility of a resistant population, reintroduction of susceptible individuals to the resistant population is feasible when certain conditions are met. Natural enemies which developed resistance to insecticides can be an important component of IPM as has been shown in the pest management in apple orchards. After all, the implementation of a successful resistance management program depends upon cooperation between different sigments of the agricutural community. Although resistance is a preadaptive phenomenon, in some cases spontaneous loss of resistance does occur without contamination by susceptible individuals. The instability of resistance in these insects implies the possible existence of a switch machanism controlling the expression of resistance gene(s). Elucidation of such a mechanism may eventually provide us with a new technical approach with which we can combat the problem of insecticide resistance.

• Korean journal of applied entomology
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• v.36 no.1
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• pp.105-110
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• 1997

Mixture study of bifenthrin and prothiofos was conducted to control insecticide resistant diamondback moth (DBM), Plutella xylostella, which had shown 581, 18, 19, 11 fold resistance to fenvalerate, cypermethrin, furathiocarb, and prothiofos in Chinju strain, respectively and 38 and 9 fold resistance to fenvalerate and furathiocarb in Seosang strain, respectively. Optimal mixture ratios of bifenthrin and prothiofos was selected against Seosang strain of DBM by leaf dipping method in laboratory and by field test. Maximum co-toxicity coefficient by dipping method was shown at a ratio of 1:50 mixture of bifenthrin 1EC and prothiofos 50EC in active ingredient(a.i.) by 243.2 and then suddenly decreased. The mixed formulation from the dipping test was examined at the cabbage field of Seosang, Hamyang. Although insecticides were reduced to half, control efficacy was similar to farmer's conventional method. In addition, the mixture combination was also more effective against Chinju DBM population which had very high level of resistance to several representative insecticides. Mixture methods of insecticides will be effective countermeasures to the resistance problem of pests.

• Korean journal of applied entomology
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• v.19 no.2 s.43
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• pp.73-78
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• 1980

Some experiment were conducted to evaluate the joint toxic action of carbofuran(2,3-Dihydro-2, 2-dimethyl-benzofuranyl methyl carbamate) and diazinon (0.0-Diethyl-0-(2-isopropyl-6-methyl-e-pyrimidinyl)-0-thionophosphate) against 3rd-instar larvae of the common cutworm, Agrotis fucosa (Butler). Acetone solutions of carbofuran or diazinon or mixture of these two insecticides, were topically applied to the mesonotum of the insect in a constant volume of $1.0{\mu}l$ per larva by means of Burkard microapplicator. Joint toxic action of carbofuran and diazinon for 3rd-instar larva of common cutworm was synergistic. The maximum synergistic effect might be obtained when the ratio of carbofuran to diazinon was 4.8 : 5.2.