European Chafer Beetle Control
Make Your Lawn Chafer Resistant
(Disclaimer: We are in the process of attributing the following material to the rightful author, believed to be a New Westminster Horticultural Society newsletter contributor. Please use the information at your discretion.)
Yes, it is possible. “Chafer free” is near impossible, “chafer resistant”—YES! You can do it!
Make your lawn healthy through continued good lawn maintenance practices. You want those roots to go deep so if the chafer is there, he will be deep (and not discovered by bird or beast) and if he does eat the roots, there are plenty more roots above him to support your lawn. Also, the healthy roots will hold your turf together, making it much harder for creatures to do damage.
Remove the moss—it is competing with your grass for nutrients. Power rake it away. If you don't, when you water, the moss acts as a sponge holding the water at the surface instead of letting it seep deep into the soil. Apply lime at the best time—in the fall and winter. Think, when do you usually see the moss forming—in the spring! You want to lime to prevent the growth of the moss—not after it has already grown.
If your soil is compacted, aerate, and if possible, top dress with very coarse sand. Rake and hose the sand down into the aeration holes. These filled holes will not collapse back in and remain as avenues for the water to flow deep into the soil.
Finally, when you do water your lawn, let the sprinkler run for 2 hours once a week instead of a light sprinkle daily. The latter entices root growth just at the surface. You want deep watering.
When you fertilize (slow release is best), water that in well as well—get it to the deep roots.
One final suggestion: If you are reseeding your lawn, look at the type of grass seeds in your mix. If possible avoid, Kentucky Blue Grass seed. Research has shown that the chafer finds the roots of this grass more delectable than those of other seeds. Don't baby that bug!
Chafer Lifecycle and Natural Controls
The life cycle of the European chafer has 3 larval stages or instars. The nematode Heterorhabditis bacteriophora is effective in controlling the first and second instar of chafer larvae and should be applied in July when the chafers are still too small to be appealing to birds and others. Watering well is necessary when using nematodes.
If third instar chafer larvae exist, especially, close to the surface, nothing will keep birds and other pests away; it is important to apply nematodes early in the development of the larvae!