Evaluation of using insect-proof nets to control Bradysia odoripaga in Chinese chive crops and the effects of nets on the growth of Chinese chives

Objectives] To evaluate the effectiveness of using insect-proof nets to control Bradysia odoripaga in chive fields. [Methods] We determined the escape rate of adult B. odoripaga confined in netting cages for 48 hours under laboratory conditions. We also conducted field trials to determine the effectiveness of netting with different sized mesh in excluding B. odoripaga and improving the growth of chives. [Results] The escape rate of B. odoripaga adults decreased with decreasing mesh size. Escape rates from 20 mesh, 40-80 mesh, to 100-120 mesh, were approximately 100%, 4.43%60.55%, and 0, respectively. Field trials showed that 80 mesh was best for excluding chives from B. odoripaga. 60 mesh was better than 40 mesh but not significantly so (P>0.05). Mesh > 70 adversely affected the growth of chives, but 40, 50, 60 mesh promoted the growth of chives in the dry season. The field experiment further verified that 80 mesh nets restrict the growth of chives, and that 40 or 60 mesh nets either improved, or had no effect, on the growth of chives compared to the control group. [Conclusion] We recommend 40-60 mesh insect-proof nets to control B. odoripaga in the field.