By Lauren Diepenbrock
Fall in Florida is not generally a time for insect, mite and other invertebrate pest populations to decline rapidly. In Florida citrus, we often see the opposite of this.
MITES
In the hot, dry end of summer and early fall, mite populations often soar, requiring management to prevent excessive damage to fruits. See The Florida Citrus Production Guide chapter on mites for management recommendations.
PSYLLIDS AND LEAFMINERS
In most years, groves will experience a fall flush, which supports Asian citrus psyllid (ACP) and citrus leafminer (CLM) populations. These generally will require simultaneous management. Growers can opt for a chemistry with efficacy on both pests by using recommendations for both ACP and CLM from the aforementioned production guide. Note that all tables include both the list of recommended products by target organism and the other organisms that they are known to control in the far-right column of both tables for each chemistry.
LEBBECK MEALYBUGS
Lebbeck mealybug populations generally see a resurgence during the fall as the temperature and humidity during this period are optimal for reproduction and juvenile survival. A 2024 Tip of the Week describes the annual population structure of lebbeck mealybug, with the juveniles (crawlers and immatures) surging through October.
Hurricane season further complicates the management of this species. Juveniles can often be dislodged from heavy rain and wind events. In fact, it takes only 5-mph winds to dislodge crawlers from a plant’s leaves. This means that hurricanes and similar wind events can serve to spread juveniles throughout a grove and/or between groves. If your grove has had a history of lebbeck mealybug infestations, planning a post-storm management spray can help in knocking back the population.
CHILLI THRIPS
In citrus under protective screen and greenhouses, a second influx of chilli thrips during fall has been recorded. Management recommendations are still under evaluation.
LOOKING AHEAD
Populations of most of the challenging pests in Florida citrus generally decline in late fall going into the winter, reducing the need for most management actions. However, there is merit in considering a dormant season spray during the winter as research has shown that it can reduce the ACP population in advance of the spring flush.
Lauren Diepenbrock is an associate professor at the University of Florida Institute of Food and Agricultural Sciences Citrus Research and Education Center in Lake Alfred.
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