Insects: Trees that have lost significant amounts of foliage can be expected flush strongly during the next few weeks. The new foliage will soon provide carbohydrates important for tree recovery and should be protected against foliage pests such as Asian citrus psyllid (ASP) and citrus leafminer (CLM). ASP typically attacks first, before young leaves have even opened. Flush that is more than 20% infested by adults could result in all young leaves being infested with nymphs and sustain significant damage. However, the greatest threat to young flush is CLM. Feather flush should be monitored for the appearance of young mines. Mines on 30% of the flush could slow tree recovery if the new flush will account for 25% or more of the total foliage.
A foliar application would be an efficient means to control these pests if the new flush were indeed sychronized. AgriMek® (5 oz per acre) and oil (5 gal per acre) has been the material of choice for controlling CLM this way. However, growers using this product for rust mite control should probably seek another alternative ( see Florida Citrus Pest Management Guide) so as not to overuse this material and lose its effectiveness through pesticide resistance. If psyllids are the main problem then Provado will probably be the best alternative. Otherwise, petroleum oil alone will provide some control for both pests. Maximum protection will be obtained if sprays are applied when the flush is about half emerged, or when the oldest CLM larvae are just beginning to curl the leaf margins in preparation for pupation.
The high cost of a soil application of Admire® that will provide a longer term alternative to control both pests, is justified on young blocks and resets. Typical rates of Admire are 1/16 oz per small tree or 1/8 oz per larger tree in 10 oz of water in a soil drench. Follow this up next spring with another drench application of Admire and monthly oil sprays to protect next year's new growth.
Several possible scenarios for what will happen next year or this late fall regarding new flush and flowering.