Development of Modular Pilot Plant for mass rearing of Insect Natural Enemies for commercial biological control purpose was conducted on the biscol year 2019. It is an adoption to insect natural enemy mass rearing standard of the International Organization for Biological Control (IOBC) as input and output based on entomological, ecological and geographical analysis. The pilot plant was developed at MJU- Biological Control Technology Learning Center located on Mae Jo University farm at latitude 18.9264 N longitude 99.0532 E. The total area of 6 rai was divided for production, research and development and quality control as well as administration units. Production performances test showed the productivity for Stink bug, Eocanthecona furcellata, Hemiptera: Pentatomidae)of the egg, nymphal and adult stages at 236,860.93, 230,418.31 and 226,040.37 per day respectively while of an egg parasitoid, Trichogramma sp. (Hymenoptera: Trichogrammatidae) was 4, 666 in average per day. The cost analysis associated with fixed and variable costs obtained showed lowest cost per unit for the production of nymphal stage at 2.97 BTH and Net Present Value (NPV) was positive. Accordingly, Internal Rate of Return (IRR), Payback Period and Benefit cost ratio (BCR) were 14.52 percent, 4 years and 9 months, and 1.83, respectively indicating thr cost effectiveness of the pilot plant. Evaluation of population ecology of target insect natural enemies and their target insect pests for further demand and supply analysis was conducted in eight northernprovinces
. It was found that target pests for the insect predators were all Lepidopteran larva damaging rice and crusiferous crops especially in family Crambidae and Noctuidae. While all the egg stage of all insect pests were target host of the egg parasite, Trichogramma sp. Although, the insect natural enemies were found naturally, but their populations were not high enough for biological control in monocropping practices indicating possibility for commercial natural enemy mass production and augmentative biological control. Finally, development of monitoring and evaluation system for the pilot plant operation was conducted by means of information technology (IT). The evaluation system indicated high level of productivity and capacity of the pilot plant and the system was promising for the implementation.