Symptoms
Small round shot-hole pattern in leaves from adult feeding. Leaves may look riddled with small holes. Larvae feed on roots. Seedlings most vulnerable — heavy attack can kill young plants.
Prevention
Use floating row covers over seedlings. Apply kaolin clay to leaves to deter adults. Plant later in the season to avoid peak beetle populations. Use radish trap crops to lure beetles away.
Treatment
Organic
Apply neem oil or pyrethrin to control adults. Use diatomaceous earth as a physical barrier. Apply entomopathogenic nematodes to soil to target larvae.
Chemical (last resort)
Apply carbaryl or permethrin to control adult populations. Treat soil with chlorpyrifos to reduce larval damage on roots. Observe PHI strictly.
Affects 1 crop
Sources
MARDI Vegetable Pest Guide; DOA Extension Bulletin