As Florida growers prepare for the spring bloom, it is time to think about a pest that thrives on citrus flowers: thrips.
Most notably, flower thrips are known to cause damage to developing flowers in sweet orange. Feeding damage can range from negligible to causing abortion of the flower or developing fruitlet. This pest is particularly challenging because it migrates between multiple hosts and since it consumes nectar and pollen, it is most likely to be causing damage during bloom, when management options are severely restricted.
While there is no standard economic threshold for this pest, it is recommended to scout blocks twice weekly prior to bud swell and treat between bud swell and full bloom to prevent flower or fruitlet loss if the pest population is increasing. For more information, consult the University of Florida Institute of Food and Agricultural Sciences (UF/IFAS) Citrus Production Guide.
In addition to flower, orchid and greenhouse thrips, which are common in most production settings, recently chilli thrips have been found causing damage to new growth in citrus under protective screen (CUPS) growing environments. UF/IFAS researchers have not developed management recommendations for this pest yet, but anticipate that materials effective for use against common thrips species should work on this species.
However, most materials labeled for thrips in citrus cannot be used in screen houses or greenhouses. To that end, several predatory insects (lacewings, ladybeetles and predatory thrips) and mites (phytoseiids) could be used to manage outbreaks. One challenge to using predators is the ability to retain them in the CUPS production environment, which gets very hot and humid and has few, if any, resources for predators to survive on when pest populations are low.
Lauren M. Diepenbrock is an assistant professor at the UF/IFAS Citrus Research and Education Center in Lake Alfred.