DENVER — Japanese beetles are out in force now. Adults chew on the flower blossoms and leaves of many plants including roses, Virginia creeper, hollyhocks and apple, plum and linden trees.
Adults are best controlled by handpicking and dropping them into soapy water. While chemical sprays are available, they vary in how long they work, what plants they can be used on and their toxicity to humans, beneficial pollinators and other good bugs like bees, butterflies, ladybugs and praying mantis.
There is one product available that will kill only Japanese beetles. It is not toxic to bees, ladybugs and butterflies and can be used on edible fruits and vegetables. Check with a garden center to see if they carry it.
Beetle traps are not usually recommended because they attract beetles by the hundreds. That being said, Rob Proctor and protege Jennifer are both trying them this year. Jennifer placed hers outside her yard. Do not place traps near flowers, trees or vegetables – the goal is to get the beetles out of the garden, not in.
Beyond killing the adult beetles, in the fall it will be important to kill the grubs or larvae. Beetle larvae are a type of white grub that feed on the roots of grasses destroying yards from below. During the fall months, grubs dine on turf roots below the surface. By the time they’re done in October, a lawn could be reduced to nothing but dirt as the grass dies.
Synthetic grub killers, beneficial nematodes and other products are all effective so do some research to prepare for a late summer or fall application.
And always make sure to read the directions to make sure products are being applied safely and correctly.
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