DIMBOA (2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one) is a naturally occurring hydroxamic acid, a benzoxazinoid. DIMBOA is a powerful antibiotic present in maize and related grasses, particularly wheat and serves as a natural defense against a wide range of pests including insects, pathogenic fungi and bacteria.
In maize DIMBOA functions as natural defense against European corn borer larvae and many other damaging pests. The exact level of DIMBOA varies between individual plants but higher concentrations are typically found in young seedlings and the concentration decreases as the plant ages.