Resistance evolution to organophosphate-based pesticides in apple and pear inhabiting arthropods of western North America extends to many classes of pest and some beneficial species. Resistance management programs to minimize resistance in pests while exploiting it in natural enemies have met with mixed success. Among beneficials, resistances have been exploited mostly among predators of pest mites. Evolution of resistant mites, leafminers, leafhopper, aphids, leafrollers and some internal fruit feeders have led to development of new monitoring methods and means to delay or avoid resistance. But it is resistance to azinphosmethyl in codling moth (Cydia pomonella) that is changing the pest control system and moving it from chemical to biologically-based means. Newly merging IPM system will depend more on use of biological, cultural, behavior and genetic controls. But more selective pesticides also will be needed to augment pheromones, resistant host plants and genetically altered organisms. These more biologically-based tactics will be prone to resistance evolution in pests as well, if used too unilaterally and/or too extensively.

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.

Lodging in the direct seeded rice cultivation on flooded paddy is being severe problem due to the lower production and grain quality at ripening stage. This study was conducted to examine the effect of Iprobenfos-metconazole (IPM) treated 50, 40 and 30 days before heading respectively as a plant regulator to reduce the lodging at ripening stage of direct seeding rice cultivation. The culm length treated with IPM, especially the 4th culm internode, was shortened more than with untreated plot, and the most effective time was at 30 days before heading. At 20 days after heading the flag leaves colour showed more greening than in the untreated leaves and the plot with IPM treatment was to be maintained longer compared to the control plot. The Nitrogen concentration of leaves with IPM was lower than in the control plot, and SiO2 contents were higher than in the untreated plot and SiO2/N ratio was increased more in the IPM plot than in the control plot. The breaking strength of 3rd and 4th culm internode with IPM treatment was higher than in the untreated plot, and the lodging index was reduced in the IPM plot significantly and the field lodging also was reduced. As the results the rice production in the IPM plot was increased more due to be higher ripening ratio and seed grain weight compared to the untreated plot to be occurred the field lodging.