Description:

• Adults are small, shiny black wasps (2-3mm long).
• When touched they curl up, roll on their side and lay motionless.
• Pupation occurs in the seed.
• When mature, the larvae is the size of a lucerne seed.
• Seed wasp larvae are white and legless.

Life Cycle:

Seed wasps become active in spring and build up population numbers on volunteer lucerne and medics. The adult female lays eggs into soft developing seeds, where the larvae feeds on the seed. When mature larvae pupate, the new adults chew their way out of the seed and pod. Round exit holes on the underside of pods indicate the past presence of wasps If not controled, lucerne seed wasp will cause economic damage to lucerne seed crops.

Management:

• Paddock cleanliness and cultural control methods are the only known long term options.
• Monitor field regularly.
• Continue to look for BGA.

Cultural control may include:

• burning harvest residues
• grazing throughout winter
• cultivating severely infested fields
• destroying flowering lucerne and medic plants on check banks and laneways
• ensuring seed crops will flower as evenly as possible, including dryland seed production
• grazing any non seed crop field before lucerne reaches the flower stage

Chemical Control:

Chemical control is possible but, with no residual activity, is often repetitive. The practice of repeated spraying on the wasps and other insects could be detrimental.

CMS First In Integrated Pest Management Copyright © Crop Monitoring Services Pty. Ltd. All rights reserved.
Pest of March Web Page created by Raymond Christinat , last updated Feb 2009
Please kindly email the author of any error.