Low temperatures and fluctuations in environmental conditions are among what researcher Ashraf El-Kereamy described as a “possible hypothesis” for the cause of lemon pitting in California’s San Joaquin Valley.

Other possible causes include what he called “overdoing a good thing” such as fertilizer and irrigation, or something affecting the integrity of the lemon’s wax layers. El-Kereamy is director of the University of California Agriculture and Natural Resources Lindcove Research and Extension Center and chief investigator for the relatively new lemon pitting issue.

In a survey this summer, valley lemon growers indicated they first observed lemon pitting in 2015. The disorder was observed in other orchards starting in 2020. It has appeared on Lisbon lemon, one of California’s most widely grown lemons. Lemons on trees grown on various rootstocks and various types of soils, from 4 to 70 years old, have been affected.

Read the full article on citrusindustry.net.