Best way to get rid of a large mealybug infestation?

Asked June 28, 2020, 8:57 PM EDT

Hi we’ve never had them before, but this year they’re everywhere....hosta, marigolds, bachelor buttons, tiger lilies, redtwig dogwood. Clearly we’ve overlooked them and they’ve multiplied. We have taken a first swing at them with a garden sprayer and safer soap, but we have hundreds of plants. I spent probably 3 hours spraying today, maybe 8 gallons of the soap water. Seems to do a good job when it hits them, but no way did we get them all. Hate to use a chemical, but don’t want to lose vegetable gardens to them. thanks.

Anne Arundel County Maryland

5 Responses

It is possible you may be referring to plant hoppers. Take a look at the photos on our web page to see if this is what you are noticing. https://extension.umd.edu/hgic/topics/planthoppers-flowers

Planthoppers feed on a wide variety of herbaceous ornamental plants but cause little damage. No control is necessary but you can wash it off the stems of your plants with a stream of water.

If this is not what you are seeing, please send us photos so we can see what you are dealing with.

Marian




Thanks, this may well be what we're seeing. They definitely hop when we hit them with water or the safer soap. Do mealybugs hop? If not, we've got planthoppers. They won't bother veggies either? Got some on squash, eggplant. Thanks again.

No, mealybugs do not hop, so it sounds like you do indeed have planthoppers. They can be fairly generalist feeders, so you can protect your vegetables if you wish, but controlling them is challenging due to their flighty nature. Contact insecticides are the only safe type to use on edible plants, and as the name implies, they only work when they can contact the pest directly. Since these insects can easily evade a spray, they are only exposed to the residue when they return, which may not be enough to substantially affect them. Systemic insecticides might work on non-edible plants, but are generally not worth the trouble for a minor pest and where treatments may negatively impact pollinators. Various insect, spider, and bird predators should discover them in time and help to control their numbers. It's not uncommon for a pest population to boom before the beneficials catch up to them.

Miri

What are the beneficials? Anything we can do to reinforce them? Last year we released some lady bugs in the garden, though I’m not sure how much good it did.

Thanks again, Miriam

We do not have a specific reference to which beneficials target planthoppers in particular, but presumably generalist predators will take an interest - jumping spiders (and any web-spinning spiders), mantids, assassin bugs, etc. Lady beetles are probably not going to impact them at all, though they will patrol for aphids and some other small pests.

General good practices for encouraging as many beneficials as possible include planting a diverse range of flowering plants (ideally native), minimizing or eliminating pesticide use, and other tips found on the "Managing Landscape Problems" document linked on this page: https://extension.umd.edu/hgic/topics/natural-enemies

Miri