Q: I have a citrus tree and the leaves are curling, dropping off, and they look pale. What is wrong with my tree?
A: I am glad you brought a clipping of the tree to me. After examining it closely, I could see the culprit was a citrus mite. The citrus red mite or purple mite, Panonychus citri (McGregor), was first recognized as a pest of Florida citrus in 1885. From the late 1930s to about 1960, it reportedly was one of the most serious economic pests in Florida citrus. Today, growers find this mite to be a sporadic pest. Citrus red mite populations are usually greatest on lemon and grapefruit, followed by orange and then tangerine. Infestations may develop any time of the year, but generally occur between November and June. Peak infestations usually occur in May or June following the major plant growth cycle of new spring flush or when prolonged dry conditions occur. Some citrus varieties such as lemon, lime and grapefruit have several minor flushes of new growth throughout the spring, summer and fall in Florida. This allows spider mites to increase depending upon favorable weather conditions. Citrus red mite prefers green developing fruit to the more mature yellow fruit. The influence of undetermined numbers of citrus red mites and weather can result in heavy leaf drop, twig die-back and even death of large limbs. Usually there is no direct effect on fruit quality although fruit drop due to heavy infestations can occur. Reducing or eliminating pesticides such as copper, copper plus oil, sulfur and lime sulfur can prevent citrus red and Texas citrus mites from flaring and becoming serious pests.