Definition of milky spore in US English:

milky spore


  • A bacterial disease of beetle larvae, including the Japanese beetle; the bacterium has been isolated and used in a commercial pesticide sold under the same name.

    Bacillus popilliae, family Bacillaceae

    • ‘I'll have to decide between a quick-acting chemical pesticide and an application of milky spore, Bacillus popilla, a bacteria that kills the grubs naturally but may take a couple of years to multiply in the soil and become effective.’
    • ‘Bt products are effective against the grape berry moth; some growers report success using milky spore as a control for Japanese beetles at the grub stage.’