Insect occurrence is closed related to crop and environment. Global climate changes as environment factor influencing not only crops but also insects on their behavior, distribution, development, survival and reproduction. Insect life stage are most often calculated using accumulated degree days from base temperature and biofix point. Temperature is also main factor to changes in moisture humidity and CO2 that effect on crop and insect development. Precipitation is another climate change on consideration factor to insect survival. Therefore, the precise impacts of climate change on insects is somewhat uncertain because it may change favor some insects while others may inhibit their development. On predicting the impact of climate change on insect is very complex exercise and need closed cooperation with experts on modeling. Some generalized predictions can be made, based on current pest distributions and severity of insect outbreaks in individual regions. At the present in Thailand, some alien insect species often present by global trades as by climate change.

• Chalerm Sindhusake(Plant Protection Research and Development Office, Department of Agriculture)