The fungus gnat Bradysia difformis has been recognized as an important and detrimental pest of greenhouse crops, and research is needed to elucidate the mechanisms to control it. However, it is difficult to breed the many generations of fungus gnat needed for the various types of research necessary to find appropriate pesticides. Indoor growing, by placing the larvae in soil, is a useful method for obtaining a large number of individual fungus gnats. This study was conducted to determine the optimum growing medium and temperature for growing fungus gnats in the laboratory and to investigate the control effect of the fungus gnat using several types of insecticides and Bacillus thuringiensis.

1. As a result of using different growing media on the eclosion rate of B. difformis, the highest eclosion rate was 88.4% with soil mix (50%)+oatmeal(25%)+shredded potato(25%).

2. As a result of four different inoculation levels of larvae on the eclosion rate of B. difformis,the highest eclosion rate was 84.7% with 1,000 larvae; this rate was shortened with the higher number of larvae inoculated per cage.

3. In the growing medium used, 3,000 eggs were better for the initial level of inoculation, showing a relatively high emergence rate and a short developmental period. Mass-rearing procedures are explained in detail.

4. Under varying experimental temperature conditions, pupation, hatching, and eclosion rates were the highest at 20℃. The fungus gnat developmental period was shortened when grown under higher temperatures. The largest number of eggs was an average of 144 at 20℃.

5. Under different larvae growing media, the higher hatching rates were 84.7% and 84.4% with water agar and potato disk media, respectively. The larval period was the shortest at 14.7 days with potato disk medium. The highest pupation to eclosion rate was 85.2% (pupation) to 82.6% (eclosion) on potato disk media. The largest number of eggs was an average of 125.6 on potato disk medium.

6. Five of 20 chemical insecticides were selected for control of B. difformis. Their active ingredients are chlorfenapyr, thiamethoxam, acetamiprid, dinotefuran, and fenthion. Three B. thuringiensis strains were evaluated by comparing their control efficacy of the fungus gnat.

Key word: Fungus gnat, Bradysia difformis, mass-rearing