Spotted green beetle

Asked October 20, 2017, 2:00 PM EDT

Over the last few days I have experienced an infestation of the spotted green beetle. It has attacked various plants in my vegetable garden , primarily the late spinach, chard, rhubarb leaves and basil. Also, they have totally decimated the petals of all of my mum plants. Besides picking them off and putting them into soapy weather, is there any other way of control? Do they overwinter? I’m located in SW Michigan, in the town of Union Pier. Thanks for any advice. Marge Spears

Berrien County Michigan

5 Responses

Good morning, Could you send me a picture of the spotted green beetle? It will make it easier to tell you how to control it. Thank you,

Here are the pictures.

Good Afternoon,
Thank you for sending the picture as it clearly identify's the beetle as spotted cucumber beetle. The following information should be helpful to you.

You can control the spotted cucumber beetle by using the following Natural less toxic pesticides: Neem oil extract or Pyrethrin.

Contact Pesticides include Carbaryl, Bifenthrin, Cyhalothrin, and Cyfluthrin.

Please read and follow directions when using any of these pesticides.

I hope this takes care of these critters. Good luck and thank you for using Ask an Expert.

This is our first late season infestation. Do they survive the winter? Should I treat the soil some way over the winter to kill viable eggs?

Fortunately, these beetles do not survive over winter and adults migrate from Southern U.S. in June.
I am sending some information regarding next years crops that might help eliminate or better control these beetles

• Traps baited with an attractant can be used to lure cucumber beetles away from cucurbit fields and for population monitoring purposes. Yellow sticky traps baited with a kairomone or pheromone lure may also reduce adult cucumber beetle.

Delaying planting or transplant of cucurbit fields until late May to mid-June, after cucumber beetles have laid their first generation of eggs (degree of lateness depends on the climate of location), has shown success in reducing crop injury from beetles in the Midwest. For cucumber and summer squash, delayed planting would eliminate early harvests, but could be a practical beetle management option for mid and late season harvests.

Row Covers, Floating row covers or plant fabrics can prevent adult beetles from landing on plants in the spring. Row covers need to be removed when plants begin to flower or pollination will be reduced. Also, weed control under covers must be handled by pre-emergent herbicides or occasional removal of covers to physically remove weeds. Row covers are more practical for home gardens and small commercial fields. Mulches Plastic or organic mulches can deter cucumber beetles from laying eggs in the ground near plant stems and may hinder movement of larvae from roots to fruits to feed. Research conducted in Virginia (Caldwell and Clarke 1998) has shown that aluminum-coated plastic mulch significantly reduced numbers of cucumber beetles on plants. These reflective mulches repelled cucumber beetles and aphids and reduced transmission of bacterial wilt and virus diseases. Feeding of cucumber beetle larvae on cucurbit fruits is more severe when fruits are in contact with moist soil. Use of mulches and drip irrigation reduces soil moisture under fruits and lessens cucumber beetle feeding on fruits.

Avoid Planting Near Other Host Plants. Preferred crop hosts for spotted cucumber beetle larvae are corn, beans, small grains, and other grasses, including weeds. Avoid planting cucurbits near these alternate hosts to help reduce spotted beetle infestations. Limiting the amount of irrigation water applied near harvest, and/or use of irrigation systems such as drip lines that limit the spread of water will reduce the likelihood of cucumber beetle injury to plants and fruits in the mid and late summer.
Cucurbit varieties with low preference by cucumber beetles (Jarvis, 1994): • Summer squash • Crookneck: ‘Yellow Crookneck’ • Scallop: ‘Peter Pan’ • Straightneck: ‘Goldbar’, “Seneca Prolifi c’ • Yellow: ‘Slender Gold’, ‘Sunbar’ • Winter squash • Acorn: ‘Carnival’, ‘Table Ace’ • Butternut: ‘Butternut Supreme’, ‘Zenith’ • Pumpkin • Baby Pam’, ‘Jack-Be-Little’, ‘Jackpot’, ‘Munchkin’, ‘Seneca Harvest Moon’, ‘Tom Fox’

Insecticides can be effective for control of cucumber beetles, but should not be used as the first or sole management tool. Combine insecticides with cultural, physical, and biological tactics for longer-term, sustainable management. In the late spring and early summer, treat when eggs hatch and before larvae move to plant roots to feed. • During mid and late summer, target high numbers of adults and larvae to prevent feeding damage to leaves, stems, flowers, and fruits. Sprays droplets should deposit on the top and underside of leaves, stems, flowers, and fruits. Also, drenching the soil surface when larvae are active can increase larval mortality. Insecticide Resistance Management To prevent the development of resistance to insecticides in the cucumber beetle population, it is important to rotate the chemical class or mode of action between applications.

I'm sorry this is so lengthy, but I think it is important to be prepared for next years crops. Thank you again for using Ask an Expert.