The trees at UC Irvine are continuing to decline, making the leafy campus a living laboratory for research on polyphagous shot hole borer, an invasive beetle that is ravaging the Southern California urban forest, reported Amina Khan in the Los Angeles Times. The borer kills by entering tree trunks and leaving behind fungus that will grow and serve as food for their young. The fungus spreads and kills the trees.

"The beauty of UCI is that it's a university, and they're used to researchers," said John Kabashima, an environmental horticulture advisor and entomologist with the UC Cooperative Extension in Orange County.

Another scientist on the project is Akif Eskalen, UC Cooperative Extension plant pathology specialist based at UC Riverside. Eskalen first identified the sesame seed-sized beetle in a South Gate avocado tree in 2012. 

Eskalen selected 130 sycamores at UCI for his experiment and divided them into 13 groups of 10. Four of the groups were treated with different insecticides; three were treated with different fungicides; and four others got one of each. Another group was given a beneficial bacteria found in some California trees that's thought to kill the fungus. A final group is serving as a control and received no treatment at all.

The scientists are allowed to cut down and section the trees, sample them, and even leave some infested trees alone. Having this flexibility is essential to understanding the success — or failure — of a given pesticide, Kabashima said: "That's why we're learning so much here at UCI."