SUMMARY1The froghopper (Monecphora saccharinaDist.) is a serious pest of sugar‐cane in Trinidad.2Of the two important aspects of the problem namely (1) the factors controlling the numbers of the froghoppers themselves, and (2) the conditions influencing resistance of the canes to, and recovery from attack, the second is considered in the present paper.3The bionomics of the froghopper are briefly dealt with.4The saliva of the froghopper is slightly acid (pH. 6.0–6.2) and it contains amylytic and oxidising enzymes.5The effect of the froghopper sucking the cane leaf is described, noting especially the peculiar and primary effects upon the border parenchyma.6Later spread of injury is described in detail and various influences at work are considered.7The water relations of the plant appear to be highly important in connection with recovery from injury and retardation of the spread of injurious effects.8Fertilisers have not been shown to aid recovery.9The problem is discussed in several of its aspects and the contents of the paper, with suggestions for further investigation, summarised on pp. 102–106. “Canes do not necessarily show serious blight when froghoppers have been abundant, nor is abundance of the insect a necessary condition for serious blight.” Agreatabundance of froghoppers, of course, is bound to have a seriously deleterious effect, quite apart from the condition of the cane. The importance of water relations is e