Corn Rootworm larvae hatch from eggs in the soil and feed underground on corn roots. The small pale larvae prune roots and tunnel into larger roots, reducing the plant's ability to take up water and nutrients. Badly damaged plants may become stunted or fall over and then curve upward as they continue growing, producing the characteristic “gooseneck” appearance. Later in the season the larvae pupate and emerge as adult beetles, which feed on silks, pollen and other plant tissue. The beetles then lay eggs that overwinter in the soil and produce the following year's damaging larvae.

How to Fix It
Crop rotation: Don't grow corn in the same location year after year. Moving corn to ground that wasn't planted with corn the previous season is the most useful control for a home garden.
Remove volunteer corn: Corn growing in last year's bed can provide food for rootworm larvae and undermine crop rotation.
Control grassy weeds: Some grasses can provide alternative food for developing larvae.
Watch for adult beetles: Beetles appearing later in summer can indicate a greater risk of eggs being laid for the following year's crop.
Don't try to rescue damaged roots: Once substantial larval root feeding has occurred, there is little a gardener can do to reverse the injury. Plan next year's rotation instead.