Trap Crops

FAR says that it is expected that all trap crops will be planted by the end of the week but completion of the planting  program is obviously weather dependent.
For the trap crops to be successful no other peas must be grown inside the controlled area. 

Volunteer peas

FAR says that it is important that volunteer plants are managed so that they cannot attract weevils this coming season.

Farmers who have previously grown pea crops, particularly last season, are advised to check for any self-sowing ‘volunteer’ plants in the areas previously planted. Either pull these out (where feasible), plough them in or treat with herbicide.

Please call MPI on 0800 80 99 66 if volunteer peas are found, all calls are confidential.
This information is needed to ensure areas of growing peas are included in future monitoring plans.

Lifecycle of the pea weevil

Adults hibernate from summer through to spring. The pea weevil spends the winter as an adult in any spot protected from the weather, including peas in storage, crevices in fence posts, around barns and sheds, debris in fields and under the bark of trees. In Australia, pine trees are a favoured hibernation site.

When daily average maximum temperatures reach above 18C the weevil emerge and search for food. If temperatures drop below 16C they become less active and are less likely to fly until the temperature rises.

The females are sexually immature and must feed on pea pollen for ovarian development. The rate of development depends on temperature and other factors and the time may vary considerably.

On average, after two weeks, the females are mature, have mated, and lay eggs on developing pods. Pairs can mate multiple times and mating continues throughout the period of egg laying (oviposition). After egg laying has finished the females die.

Adult pea weevils cause no damage to peas. They are essentially pollen and nectar feeders and if they cannot find pea pollen they can feed on other plant pollen, but they must find pea plants with developing pods on which to lay eggs and produce another generation.

After 2-4 weeks, the eggs hatch and the larva bore directly through the pod wall and into the developing pea (i.e. insecticide at this stage is going to have little or no effect). Only one larva develops in a single seed and the larva feeding on the seed destroys its viability.

After 40 days (5-6 weeks), the larvae pupates in the seed after having pre-prepared an exit hole in the larval stage.

About two weeks later, the adult beetle develops. Some beetles emerge immediately to find hibernation sites. Others remain in the seed until they are disturbed or until next spring when the seed is planted in the ground the weevil exits the seed and may wait in the crop for flowering to occur.

For the eradication phase to succeed, pea weevil must be captured and destroyed over the next few months as they search for podding peas on which to lay their eggs.

Surveillance outside the controlled area

Monitoring surveys have started in the Gisborne area and are expected to start in other regions in the next few weeks.

Paddocks continue to be added to the GIS maps and training sessions in monitoring techniques and use of the tools have been completed.

FAR reports that the presence of pea weevils has not been confirmed outside the Controlled Area.