Applying pesticides that aren't necessary is a waste of time and money and is an unsafe practice. 10 Avoid cultural practices that promote pest populations. Incorrect or incorrectly performed maintenance practices stress plants and make them more susceptible to pests. For example, excess fertilizer and water produce tender succulent tissue that's ideal for the development of many insects and diseases. Pruning incorrectly can also create suitable conditions for insects or disease.
Insufficient water promotes mite development.
Lack of thinning can promote diseases such as powdery mildew and leaf spots.