The pea leaf weevil (Sitona lineatus) is an exotic pest that threatens field pea and faba bean production as well as lucerne pastures overseas. The insect causes damage at multiple stages of its life cycle, leading to significantly reduced yields. Australia and New Zealand remain free of the pest.
Much of the damage caused by the weevil is through feeding on the nitrogen-fixing root nodules of the plant, resulting in weaker plants that are less drought tolerant and produce less seed. Large pea leaf weevil populations can destroy up to 90 per cent of the root nodules.
Adults also damage crops through feeding on the leaves and growing point of seedlings. In addition to field pea and faba bean, adults will also feed on chickpea, red root pigweed, trefoil, lupines, clover, alfalfa, vetches and other perennial legumes.
Adult pea leaf weevils are slender, greyish-brown beetles about 5 mm long with a broad-shaped snout. Three light-coloured stripes extend length-wise down the thorax and sometimes the abdomen.
Pea leaf weevil larvae are C-shaped and measure about 3 to 6 mm in length. They are soft-bodied and milky white with a dark brown head.
Pea leaf weevil adults can be confused with other weevil species including the sitona weevil, small lucerne weevil and the spinetailed and vegetable weevils.
The larvae look similar to sitona and small lucerne weevils as well as cock chafers.
Adult feeding damage consists of notches in the leaf margins, cut in close sequence producing a scalloped effect. In most instances only minor damage occurs, but severe ragging of the leaves or complete defoliation can occur during heavy infestations.
Check plant roots, where the major damage is done by larvae feeding on nitrogen root nodules and roots of legume crops. Larvae feed on nodules by chewing a hole through one end and consuming the contents.
Pea leaf weevil is most often spread by moving infested host plant material, soil and machinery. Larvae can be transported in infested soil of potted plants.
Once transported to a new site, adult weevils spread locally by walking or flying short distances.
The current range of pea leaf weevil includes most of its native Europe as well as the UK. It was first discovered in the US in 1936, and occurs in the west of the US and western Canada. Pea leaf weevil also occurs in parts of North Africa.
Ensure all machinery coming on to your property is thoroughly cleaned and inspected in a designated clean or wash down area before going out onto paddocks. Inspect all plant products coming onto the property.
Early detection is crucial in stopping or slowing progress of a new pest. Monitor your crops regularly for anything unusual, and call for assistance to help identify anything unfamiliar without delay.
If you see anything unusual, call the Exotic Plant Pest Hotline on 1800 084 881
Ensure all machinery coming on to your property is thoroughly cleaned and inspected in a designated clean or wash down area before going out onto paddocks. Inspect all plant products coming onto the property.
Early detection is crucial in stopping or slowing progress of a new pest. Monitor your crops regularly for anything unusual, and call for assistance to help identify anything unfamiliar without delay.
If you see anything unusual, call the Exotic Plant Pest Hotline on 1800 084 881