When your garden is being skeletonized by Japanese beetles, those pheromone traps sure do look tempting! And if you hang one in your yard, you’ll certainly be rewarded with a full bag of squirming beetles on a regular basis. But do they actually reduce the number of beetles in your yard, or attract more to it?
Japanese beetles arrived in the U.S. in the early 1900s, and have spread across much of the eastern part of the country. They attack the leaves of a wide range of plants including trees, flowers, fruits, and vegetables.
How Japanese Beetle Traps Work
Japanese beetle traps release both a sex pheromone and a floral scent, are very effective in attracting adult beetles. They fly to the trap in droves, where they crawl or fall into the bag and can’t get out. You simply dispose of the bag, and put on a fresh one, and the process starts all over again.
The problem is, the traps attract about four times as many beetles as would normally be in your yard, and only 50% to 75% of them will actually end up in the bag. The rest bounce off and make their merry way into your garden, where they vigorously set about munching your plants and laying plenty of eggs for next year’s beetles.
So, yes, technically speaking, the traps work like a charm in attracting beetles. But in terms of actually reducing the beetle population around your plants, they may be helping your neighbors more than you.
Like other pheromone insect traps, Japanese beetle traps work best as a survey tool. By putting one out in early summer, you can get an idea of how bad the infestation is, which can help you make better decisions about how aggressive you need to be in your control program.
They also work great if you have a very small, isolated population of beetles that can easily be lured and controlled by the trap. In most cases, though, if the beetles are in your yard, you can bet that they’re all over the region.
Tips for Using Japanese Beetle Traps
If you’d like to try using Japanese beetle traps, follow these tips:
- Keep a Distance: Place the traps as far away as possible from the plants you’re trying to protect.
- Install Downwind: Make sure to hang the traps downwind from your garden, so that as the beetles follow the wafting scent from the trap, they won’t be flying right over your garden and be tempted to stop for a munch.
- Get Neighbors Involved: Since beetles can travel for up to a couple of miles, a community-wide control program, with traps placed strategically throughout the area, works better than a few isolated traps in yards.
- Keep Traps Fresh: Not only can the lures go stale, but the bag full of dead bugs can cause the trap to stop working. Replace the lure according to package instructions, and replace the trap bag every few days.
- Time It Right: Adult beetles are most active during June, July, and August. Traps are only effective when the adults are out, particularly during the early season before they’ve done too much mating and egg-laying.
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