In the last few weeks, several pest control advisers contacted me about the lilac borer (also called ash borer), Podosesia syringae (Family: Sesiidae). Lilac borer adults are clearwing moths. Female lays eggs on the stem (young trees) and/or branches of the olive plants. Upon hatching, young larvae enter into the cambium layer of the plant and begin to feed on. One larva can kill a young olive tree as one is enough to girdle the stem. We have observed multiple young trees died due to this pest in the last 2-3 years in olive groves in San Joaquin county. They also infested branches, trunks of the mature olive orchards and cause damage to the plant. I wrote an article about this pest's biology with some preliminary trapping data in 2019 in UCCE Field Notes. Please find the pdf copy of that article below:

Lilac Borer Biology_Field Notes May2019

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