English: The distribution of chemical defenses over a root system, and how this affects below ground herbivores.
Red indicates the highest defense level in the root system and yellow indicates the lowest level. Chemical defenses are generally highest in the taproot (red), followed by the lateral roots (orange) and the fine roots (yellow). Some insect herbivores, like the cabbage root fly, can deactivate a plant’s chemical defenses and can eat the taproot where defenses are highest. Other herbivores, like the European June beetle, cannot deactivate plant defenses and therefore they eat the fine roots, where chemical defense levels are lower.