The Japanese beetles are out and feeding! These adult forms of the same grubs that infest your lawn are beginning to feed on some of their favorite plants and trees. They are not yet at their worst, so it is a great time to get them taken care of.
Japanese beetle damange compliments of Iowa State University
Japanese beetles emerge from the turf around the last week of June through July. After emerging they will feed, mate, and lay eggs through the middle of August. During this time period is when you will see them doing damage to your landscape. Japanese beetles skelotonize the leaves by eating the tissue between the stems and veins of the leaf. They can feed very quickly and cause a lot of damage. With over 300 host plants, the list of what they will not eat is shorter than what they will!
Recently beetle bags or beetle traps have become popular in residential landscapes. These traps work by emitting a pheromone to attract the beetles and once they fly into the bag they are unable to fly out. These bags work great at attracting beetles, but that is the exact problem you want to avoid. We do not recommend using these beetle bags as they will just attract more beetles than they will trap. I think the only good use they would have for your beetle problem is when your neighbors use them!
An insecticidal application to the affected/threatened plants and trees is effective in protecting them from damage. Since their feeding lasts only 6-8 weeks one application is usually sufficient to control the damage to a tolerable level. We are currently spraying these applications and are achieving great control this year.
