Ants killing my Broccoli and Romanesco starts?

Asked April 26, 2014, 8:10 PM EDT

All of my Broccoli and Romanesco Starts seem to be wilting, falling over and then dying one by one. When I looked closer at them the stems there are ants swarming just below the surface of the dirt, and when I pulled a dead plant out it seemed to not have and roots left. I researched online and found that other gardeners having the same issue, but never really found a straight answer on any of the forums for what is causing this and how to deter the ants or other pest that could be causing this to happen. there are no signs of aphids or cut worms. I tried diatomaceous earth and cinnamon. would love your advice! I'm so frustrated.

Multnomah County Oregon integrated pest management vegetable gardening

1 Response

Those tiny black odorous house ants are particularly persistent in their efforts and will return from time to time throughout the year. Yes, they forage for crumbs and the like but they also come indoors for water.

To gain the upper hand against odorous ants or any other kind of house-invading ant, you must be just as persistent as they are. Even so, you aren’t likely to get rid of them. The most effective means of managing house-invading ants is by using commercially formulated baits, combined with sanitation. Baits work well because the ants share it with colony members. The pre-formulated products most effective against odorous ants contain either borate as in Terro or fipronil as in Combat Max Gel.

If the ants are still coming indoors after three weeks, obtain fresh supplies of pre-formulated ant bait containing a different active ingredient. Commercially formulated baits are available at hardware stores and big box stores.

If the above methods don’t work to your satisfaction, consider hiring a pest control company as they have materials unavailable to home users. Even then, sanitation is an important part of treatment. Also understand that odorous house ants are the Number One “call-back” insect for pest control companies.

Resource for you:
“Ants” is a general information article from the University of California which discusses various kinds of ants, one of which, the Argentine ant, isn’t yet in Oregon.