Not all pest problems can be solved by manipulating cultural practices in the plant environment or by using biological control agents. In these cases, pesticides become the second or third line of defense. The pest must be properly identified and monitored with reliable techniques to establish acceptable levels in your landscape. Optimum control of many insects and weeds is achieved at a particular stage in its life cycle, which is usually during the early stages of development. For example, mole crickets are most susceptible to chemical control when they are small, usually during the months of May or June. Chemical applications at other times are less effective.