The area of coconut leaflets was estimated with multiple‐regression equations using parameters such as frond length, width of the leaflets and the area of corresponding leaflets from the youngest frond, which is usually undamaged. The error of one estimate was commonly less than 10% provided enough parameters were available. Measuring the area of leaflets reduced by leaffeeding insects with a leaf‐area meter, and comparing it with the above results, gave estimates on the defoliation level. Examples for damage caused bySexavaspp. are given and discussed.