Peter: Because the leaves of mildly drought-stressed plants are tougher in texture than the leaves of abundantly watered plants, insects prefer to feed on the leaves of abundantly watered plants  Ttherefore, to minimize crop damage, farmers should water crops only just enough to ensure that there is no substantial threat, from a lack of water, to either the growth or the yield of the crops  Jennifer: Indeed
In fact, a mildly drought-stressed plant will divert a small amount of its resources from normal growth to the development of pesticidal toxins, but abundantly watered plants will not
It supports Peter's argument by offering an explanation of all of Peter's premises.