Brain,the so called June Drop, or excessive shedding of the young fruits, is mainly caused by extremely hot and dry weather, Therefore container trees are commonly not involved with June Drop if kept from overheating. However, for in ground trees June Drip occurs commonly following worm dry periods. In the desert and semi-desert sections of California and Arizona this drop can be so heavy, especially with navel orange varieties, that the yield is commonly greatly reduced, sometimes so much so that production is rendered unprofitable. Other orange varieties and grapefruits are also affected, but no so seriously. June Drop is largely caused by the severe strain on the tree resulting from low humidity, hot dry weather, which leads to excessive transpiration and loss of water. As a result of this condition fruit abscission is stimulated. - Millet.
