EXETER – California citrus growers faced significant pest challenges this season due to the unprecedented rainfall from atmospheric rivers. The unusual weather pattern disrupted typical citrus thrips timing in orchards and led to uncontrollable conditions in the field.
Citrus thrips are small, orange-yellow insects with fringed wings that feed on the tender leaves and fruit of citrus trees, especially under young, budding fruit, according to the University of California’s Integrated Pest Management system. Thrips typically feed on navel, mandarin and desert citrus varieties after the insects hatch from their eggs in March, just in time for the spring bloom of the fruit. The pest typically dies off once temperatures reach below 58 degrees.
Exeter-based California Citrus Mutual (CCM) is a non-profit trade association advocating for California citrus growers, which produce 90% of the nation’s fresh grown citrus. CCM’s Pest and Disease Task Force reported that some growers have experienced exterior fruit scarring on as much as 80% of the fruit on individual blocks, primarily affecting navels but with varying impacts to mandarins, lemons and other citrus varieties.
“It’s been an extremely challenging pest season for citrus growers,” CCM President Casey Creamer said. “The industry did its absolute best in trying to control this unprecedented thrips season. Growers bear that cost while also facing the reality that the pest pressure will result in decreased returns in the marketplace.”
Once they hatch, the pest leaves scabby, grayish or silvery scars on the rind. Second-instar larvae do the most damage. As the fruit grows, damaged rind tissue moves outward, commonly called a ‘ring scar.’ A second type of scarring can occur around the stylar (bottom) end of the fruit. The scarring can be severe enough to deform the shape of the fruit.
Visual effects from thrips have no effect on the interior fruit quality, taste or texture. Consumers can still expect the same exceptional eating experience they are used to with California citrus with higher volumes of choice fruit. Fancy fruit, with minimal external scarring or damage, will be a premium commodity this season.
The CCM Marketing Committee estimates that 30% of the navel crop has thrips scarring and the utilized volume will be 8% to 15% under the previous season’s production due to thrips. The committee also estimates that the mandarin and lemon crops will also be down 5% compared to the previous season’s utilized production.
“Despite these challenges, our growers remain optimistic about the fruit quality on the tree this season. The overabundance of water has reservoirs full and has reinvigorated the groves after three years of extreme drought conditions,” Creamer said.