Why are there so many millipedes after rain?
Why are there so many millipedes after rain?
After heavy rain, many millipedes appear in the yard—there is a reason.
Reasons for increased numbers after rain
- Millipedes usually hide under soil and leaf litter.
- Rain displaces air from the soil, forcing them to emerge.
- They come out in large numbers seeking dry areas.
- After rain, air humidity is high; millipedes breathe through spiracles and require high humidity for proper respiration, so they are especially active.
- Thus, after heavy rain, they emerge in large numbers on the ground and along walls.
- Peak activity occurs 1-3 days after rain, then gradually decreases.
Post-rain is the best time for treatment
- They appear in concentrated numbers, making it an ideal time for targeted spraying.
- Spray bifenthrin when they are clustered—more effective than usual.
- After spraying, sweep away the dead bodies.
- Reapply along wall bases after rain; one treatment lasts a long time.
- Bifenthrin residue is rain-fast once dry.
Precautions
- Large numbers after rain are normal; do not panic.
- Focus on removing standing water and puddles around the house, otherwise they will accumulate more.
- Close doors and windows promptly after rain to prevent entry.
- Ensure good yard drainage to reduce standing water.