(Photo: Citrus Pest and Disease Prevention Program)

Citrus pests decrease production in California.

Natalie Willis, Reporter, Valley Ag Voice

The California Department of Food and Agriculture ordered a quarantine for over 101 miles in Ventura County two weeks after the detection of Huanglongbing disease in an Asian citrus psyllid cluster. HLB was detected in two citrus trees on a residential property in Santa Paula.

The disease was detected from plant material from one orange and one lime tree on the property near the initial sample detection of an HLB-positive psyllid. According to Hamutahl Cohen, Entomology Advisor with the University of California Agriculture and Natural Resources Department, when HLB was detected in Florida, it spread rapidly.

“I previously worked as an extension agency with the University of Florida IFAS Extension,” Cohen said in an email. “Due to HLB, orange yield in Florida decreased about 40%. In addition to causing low fruit yields, HLB results in fruit that tastes less sweet.”

Cohen noted that following low fruit yields, Florida growers shifted away from growing citrus in favor of other crops.

The detection in Santa Paula prompted the removal of the infected trees as well as a mandatory survey within 250 meters of the find site. The quarantine prohibits the movement of all citrus nursery stock, host plants, or plant parts out of the area, but movement of commercially cleaned and packed citrus is allowed according to the CDFA.

The initial detection of the insect was found in an area adjacent to many citrus orchards, and there is no cure for the HLB disease. Growers in that region will likely spend more time and resources to monitor and treat orchards for ACP insects, Cohen explained.

Infection with HLB results in shoot and leaf yellowing, malformed seeds, small fruits, and will ultimately kill the tree,” Cohen said. “All types of citrus, including lemons, which are frequently grown on the coast, are vulnerable.”

The CDFA implemented a treatment program to reduce ACP infestations in citrus trees and, in partnership with the USDA and local agricultural commissioners, are pursuing a strategy to control the spread of HLB.

Along with a potential outbreak of HLB, the California citrus industry had an unprecedented year in terms of pest and weather damage, according to a press release from California Citrus Mutual. Reports from its Pest and Disease Task Force indicated that some growers experienced exterior fruit scarring on roughly 80% of individual blocks, primarily affecting naval.

However, visual and aesthetic effects do not affect the interior fruit quality, taste, or texture, CCM explained. Regardless, “fancy fruit” with minimal external scarring will be a premium commodity this season, according to the press release.

Excessive rainfall also encouraged a higher level of Thrip insects that affected production yields. The CCM Marketing Committee estimated that the navel crop will be 8% to 15% under the previous season’s production due to thrips, and the mandarin and lemon crops will be down 5%.

“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.”

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