This is always a sad scenario.  The National Pesticide Information Center recommends as follows:  

Without knowing what or how much pesticide is on/in the edible plants, the risks to human health are unknown. If you know who applied the products, consider asking them for the EPA registration numbers, active ingredients, and/or labels of the products. This will show you the active ingredients involved and if any food uses are permitted by the label. If a pesticide was not used according to the label, the risk of ingesting the impacted plants is unknown. Some pesticides are meant to be used on certain edible plants. However, the risk may increase if more of the product got on the plants than the label allows. People not following pesticide label instructions put plants and the people eating them at risk.

Ultimately, you will have to make your own decision about what to do next based on the information you have, and the level of risk you’re comfortable with. When there is an unknown risk to your plants, refraining from eating them is the only way to completely eliminate risk. Consider avoiding composting contaminated plants to keep residue out of your compost.

http://npic.orst.edu/faq/garden-drift.html

It seems that the same recommendation applies:  https://hyg.ipm.illinois.edu/article.php?id=1247  Even though the food is underground, the plants can potentially transfer the pesticide to the root as it nourishes it.  If the pesticide injury was caused by someone other than yourself, you can file a complaint with the Iowa Department of Agriculture and Land Stewardship Pesticide Bureau,<personal data hidden> or by emailing the information to pesticides@Iowa Agriculture.gov