Thursday, March 31, 2011
Problems with Citrus Trees; Suspicion of Citrus Greening
SITUATION: Having problems with 30 to 40 years old citrus trees. Have lived in the area for 12 years and the tree has done very well. However, this year something is wrong. The citrus trees are full with hundreds of very small fruit. Normally, the fruit is sweet and eaten by the birds and squirrels. The fruit is usually picked much earlier than this. This year, the fruit is small and sour. The birds and squirrels have not touched it and the leaves are yellowing and beginning to curl. Is this the citrus greening disease we have heard about? I did not see other diseases like this when I tried to look it up.
RESPONSE: Wow, citrus can be tough to work with sometimes. In this case, the trees are very old and it may not take too much to cause them to decline. You should have continued watering on a regular basis during the winter by providing at least 1" of water per week. You should be applying a "citrus fertilizer" four times a year. If you notice any unusual cracking of the bark on the trunk near the soil line suspect foot rot an contact a Certified Arborist for assistance. If you control weeds and grass growing under your citrus trees with Round-Up make no overspray is landing on the trunk of the citrus trees. Because all the citrus trees are having the same problems at the same time, my first suspicion is that they were not being watered with a sufficient amount of water over the past 4-6 months. Secondly, water and fertilizer are closely tied together. Incorrect watering practices can lead to nutrient deficiencies although you are providing fertilizer often enough and in sufficient quantities.
If you suspect Citrus Greening, please call the Department of Plant Industry (1-800-282-5153) for an inspection of your trees. Please do not bring possible greening samples to the Extension Office as you will be transporting potentially infectuous material into areas of the County where Citrus Greening may not be found.