Control of pests of pecan (Carya illinoensis K. Koch) nuts involves multiple challenges. Appropriate application timing is a crucial first step, followed by complete coverage of the nut surface area by contact insecticides, while dissipation of pesticides because of numerous biotic and abiotic factors affects pest control effectiveness through time. Increase of untreated area because of growth of the nut surface, exposing a non-protected part of the shuck to pest attack is rarely considered. We measured the area of pecan nuts at weekly intervals to establish a surface area growth pattern that indicated increase between 15 and 30%. The rapid growth left a considerable area exposed to insect attack, or having less concentration of insecticide on the expanded treated area only a week after the previous application of insecticide make nuts more susceptible to pest attack. The information can be useful when reapplying pesticides to control pests of pecan nuts.