As post-pandemic travel ramps up this summer, the California Department of Food and Agriculture is urging people to leave their home-grown citrus fruit at home.

Traveling with citrus fruit or plant material can unknowingly spread the Asian citrus psyllid, which can carry the deadly tree disease huanglongbing, the agency advised on its Planting Seeds blog. California's $3.4 billion citrus industry has so far avoided HLB infections in commercial groves.

Related: UC develops map to track HLB in citrus

“The best way to stop the spread of the disease is to stop the spread of the pest, which is why we urge residents not to transport their backyard citrus into and out of quarantine zones, bordering counties, state lines or international borders,” said Victoria Hornbaker, director of the Citrus Pest and Disease Prevention Division at the California Department of Food and Agriculture. “Community support is critical to saving California citrus and residents must work together to ensure our iconic citrus crop can continue to bring joy to people across the state.”

Quarantines currently in place throughout California limit the movement of citrus plant material across state and international lines, and between areas where the psyllid and disease have been found, the CDFA warns. Portions of Southern California are currently under an HLB quarantine in numerous communities of Los Angeles, Orange, San Bernardino and Riverside counties.

Related: How long can California citrus continue to dodge HLB in commercial groves?

According to AAA Travel, more than 37 million Americans will travel on Memorial Day weekend this year – a 60% increase from 2020, the CDFA notes. The agency encourages tree owners to share fruit with family and friends within their quarantine area, and urges them to remove leaves and stems and wash the fruit thoroughly.