Rice water weevil

Lissorhoptrus oryzophilus

The rice water weevil adult (about 0.125 inch or 4 mm long) has a prominent beak and is gray with a dark marking on its back from the base of its head to the middle of its wing covers. It is distributed throughout the Sacramento Valley, the upper San Joaquin Valley, and central San Joaquin Valley (Merced County). It overwinters as an adult at the base of grass clumps, in weedy debris on levees and ditch banks, or in soil crevices.
DAMAGE: Rice water weevil is the most economically damaging of the invertebrate pests found in California. Root pruning by larvae is the major cause of reduced yields. Plants with damaged roots may become stunted and lose yield through reduction of tillers and panicles or because maturity is delayed. Reduced tilleringand slower growth also allow weeds to become better established. The heaviest infestations and most serious damage can be expected to occur between late May and July within 15 to 20 feet of the margins of the fields and levees, where weevils are concentrated; moderate damage can occur in areas 20 to 35 feet from levees.

Plant Protection Products