Infestations begin in springtime. It is easier and more cost effective to overcome infestations during the initial stage, such as in the nymphal stage. Make it a routine to monitor the field regularly and search plants for the above signs on younger foliage.
Maintain a healthy canopy and avoid long periods of time when trees are under stress due to lack water\proper irrigation or fertilization; healthier canopies are less likely to be attacked.
When drought conditions are present, adjust the size of canopy to with a water regime and prune the trees accordingly.