Study Shows Mandarin IPM Needs Work

Len Wilcox California Corner, IPM, Pests

Tango mandarins are ready for harvest in a California citrus grove.

According to a study published in the Journal of Economic Entomology, current integrated pest management (IPM) techniques used in California mandarins may need to be adjusted to allow for differences between mandarins and oranges. The study suggests that following guidelines for oranges may lead to an overuse of pesticides in some situations.

Almost all mandarins in America are grown in California, providing almost half of the nation’s citrus production. But growers have evolved the IPM used in mandarins from navel orange orchards, and it may not provide the most effective way to deal with insect threats to mandarins. The study was conducted by University of California (UC) scientists Elizabeth E. Grafton-Cardwell, Bodil B. Cass, Lindsey M. Hack and Jay A. Rosenheim. An article about the study appeared in the May issue of Entomology Today.

The study used a data mining or ecoinformatics approach to compile and analyze production records collected by growers and pest control advisers. Ecoinformatics, or ecological informatics, is the science of information in ecology and environmental science. It integrates data to define entities and processes with language common to both humans and computers. It is a new, rapidly developing area of study.

The UC study gave researchers an overview of direct pest densities and their relationships with fruit damage for 202 commercial groves in the central valley of California, the main production region of the state. The research showed pest densities were different among mandarins compared with sweet navel oranges. The mandarins showed considerably less damage from pests than did the navel oranges.

These results led the researchers to believe that some pesticides may be overused in some species of mandarins. Mandarin-specific research and recommendations would improve citrus IPM.

The study can be read online in the Journal of Economic Entomology at

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About the Author

Len Wilcox

Correspondent at Large for Citrus Industry Magazine and AgNet West