In the Imperial Valley, larvae feeding on roots has caused serious damage on occasion. This damage is easily confused with cavity spot symptoms. Relatively low populations can cause economic damage when plants are in the cotyledon or first leaf stages. Baits are not effective. Once plants have several true leaves, they can tolerate several beetles per plant without damage.
Older plants are even more tolerant.
Insecticide treatment should rarely be required, but if it is, one application should suffice. However, chemical treatment may disrupt biological control of aphids and whiteflies. Avoid drift and tailwater runoff into surface waters. Do not apply within this many days of harvest. Permit required from county agricultural commissioner for purchase or use.