Beetles, Beetles and more Beetles! by Joe Magazzi

Japanese beetle from Joe's house

It is that time of the year again - July 4th barbecues, extensive heat and yes - the first sightings of beetles!  The beetles you see now that are busy decimating your plants are in their last adult life cycle stage. These beetles are the adult form of white grubs (the larvae).  Once these adults decimate your landscape and crops, the beetles will lay their eggs in the later summer/early fall to start the next life cycle.  The eggs will develop into young grubs as the summer winds down, and those larval beetles will then turn their attention to the next headache for you…eating your turf grass and plant roots. With multiple ways of causing problems, beetles and their grubs will provide you with an entire season of angst!  Have no fear, however, Green Earth Ag & Turf has many organic methods to control these pests and help you spend more time enjoying the summer instead of fighting insects.

Like clockwork, the Japanese Beetles showed up in New England on July 1st. We spotted our first a day late on July 2nd (must have been a bad layover on their flight).  If they have not been spotted yet in your area, expect to see them in the very near future.  There are, however, more than just Japanese Beetles to worry about this time of the year.  There is an extensive list of beetles that can damage plants, including Asiatic, Oriental and European Chafer Beetles. These pests do not only cause aesthetic damage but can have a huge economic impact.  For example, the Japanese Beetle alone is estimated to cost the turf and ornamental industries $450 million per year to manage (Potter DA, Held DW. 2002. Biology and management of Japanese. Annual Review of Entomology 47: 175-205).  Some of the Japanese beetles' favorite plants are roses and grapes, and they can decimate a soybean crop and cause heartache for farmers.

Asiatic Garden Beetle from bugguide.net

Not to be outdone is the Asiatic Garden Beetle.  Because this beetle feeds at night, the damage that is seen on plants is often blamed on the more prevalent Japanese Beetles. The Asiatic Beetles can cause a tremendous amount of damage and they are much more difficult to physically control (by squashing) -unless you are a night-owl with a miner’s hat.  Favored hosts include butterfly bush, rose, dahlia, aster and chrysanthemum, according to the UMASS Extension.  Purdue University states that this pest will be seen from mid-July to mid-August, but may be found anytime from late June through October. 

Leaf damage - Asiatic Beetle

To spot and differentiate the damage from Japanese Beetles, adult Asiatic Garden Beetles do not skeletonize leaves, but rather strip, shred and notch the foliage. Oriental Beetles don’t feed much as adults, but they will become a topic of discussion when we address the grubs in the next few weeks – as they particularly enjoy the roots of turf grasses, perennials and nursery stocks…plants which we value greatly in our landscapes.  This also holds true for European Chafers, which have already been out for some time in the form of June Bugs. 

Japanese beetle damage - maine.gov

Most of the damage done by beetles is a group effort - once a single beetle starts to damage a leaf, scents are emitted from the plant that then attract more of their friends. For this reason, we recommend scented oils as very effective organic controls for these pests.  The oils not only directly interfere with the octopamine neuroreceptors (a key neurotransmitter in many insects that regulates movement, heart rate, behavior, and metabolism) but it may mask scents that attract group feeding and attraction of other pests.  

We have found great success with Ecotrol Plus, a mixture of rosemary, peppermint and geraniol oils. Besides smelling great, a spray of EcoTrol every week for a few weeks will go a long way to stopping the feeding cycle and saving your plants. Unlike pre-emergent oils, the concentrations of these oils are very low and safe to use all summer in the heat and bright sunlight.  We also suggest the biological control GRANDEVO , which is an advanced, cross-spectrum insecticide that offers protection against chewing and sucking insects. Its complex actions on pests — oral toxicity, reduced reproduction and repellency, provides up to 14 days of residual control. GRANDEVO is also OMRI listed; both EcoTrol and GRANDEVO are approved for ornamental and food crops.

As always, Green Earth Ag and Turf, your R & D Department, has your organic pest, disease and weed controls ready to go! Enjoy more, and worry less this summer! Give us a call at 866-374-5101.