Pigweed flea beetle infestation in native plant garden

Asked June 17, 2019, 4:22 PM EDT

I have a large native prairie plant garden for pollinators. It is suddenly infested with what appear to be pale-striped pigweed flea beetles. They are tiny, black and yellow striped with orange-red head and they both jump and fly. Leaf damage is evident on many different species such as Monarda, Giant hyssop, Vervain, even Creeping Charlie! My research tells me that my method of no cultivation, just cutting back old plant stalks in the spring, may be allowing adults and eggs to winter over. The garden is four years old in the same spot. I do not want to use even organic controls that will harm other insects. Do you have advice for me?

Hennepin County Minnesota

1 Response

“Adult flea beetles overwinter in plant debris. To destroy possible refuge sites of adult flea beetles, maintain field sanitation by keeping field margins free from weeds. In case of infested fields, deeply disc plant residue after harvest. Crop rotation with nonhost plants (e.g., cereal grains such as wheat) and maintaining good plant health (e.g., no water stress) are also important for managing flea beetles in alfalfa production.” This quote is from the following website: http://ipm.ucanr.edu/PMG/r1302111.html Another common method of controlling weeds and pests in praire gardens is to control burn the fields periodically in early spring. It gets the weeds and debri because weeds come up weeks before the prairie plants. See: https://extension.umn.edu/planting-and-growing-guides/planting-and-maintaining-prairie-garden