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Be mindful of chemical withholding periods if spraying for native budworm

Caterpillar activity

  • Narra Tarra
  • Walkaway
  • Yuna
  • Kellerberrin
  • Burracoppin
  • Varley
Native budworm caterpillar
Native budworm caterpillar. Photo courtesy of: DPIRD.

Technical officer Joanne Walker (DPIRD) reports finding three native budworm caterpillars (0-5mm) per 10 sweeps in a lupin crop near Narra Tarra and two caterpillars (5-10mm) per 10 sweeps in a canola crop near Walkaway.

Technical officer Amber Balfour-Cunningham (DPIRD) has found an average of five budworm caterpillars per 10 sweeps in a lupin crop near Yuna.

A farmer just north of Kellerberrin reports finding seven caterpillars per 10 sweeps in a lupin crop.

Another farmer near Kellerberrin has found approximately one native budworm caterpillar per 10 sweeps in a wheat crop. The caterpillars were mainly found along the edge of the crop. They are feeding on some of the wheat heads as well as the leaves, but overall the damage is minor and does not warrant a control spray.

A farmer near Burracoppin has found two budworm caterpillars per 10 sweeps in a lupin crop.

A budworm trapper reports finding five budworm caterpillars per 10 sweeps in a very early sown lupin crop near Varley, the caterpillars are just beginning to show an interest in the lupin pods. A nearby faba bean crop had less than one caterpillar per 10 sweeps (one grub per 50 sweeps).

Native budworm moth trapping surveillance

  • Usual automated and manual trapping locations
An adult native budworm moth.
An adult native budworm moth. Photo courtesy of: Alan Lord (DPIRD).

Native budworm moth numbers reported by volunteer farmers, agronomists and DPIRD staff have again mostly remained low for most of WA’s wheatbelt over the past week. The higher numbers reported this week include: Badgingarra (49 moths), Binnu (35), Dowerin (24), Dalwallinu (23) and Narra Tarra (12)

Growers who may be contemplating spraying maturing canola, lupins and field peas should be mindful of chemical withholding periods (WHP) and to check chemical labels before spraying. Minimum times required between the spray application date and harvest or windrowing crops can vary from 0-28 days (see Table 1 below).

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Table 1 Withholding periods in days for harvest/swathing; registered insecticides for native budworm.
Active ingredient Canola Lupins Field peas
Alphacypermethrin 21 28 28
Chlorantraniliprole N/A 28 28
Cypermethrin 21 28 28
Deltamethrin 7 7 7
Emamectin 14 N/A 21
Esfenvalerate 14 14 14

Gamma-cyhalothrin

7 14 7
Lambda-cyhalothrin 7 14 7
Methomyl 7 7 7
Permethrin N/A N/A 2
Spinetoram 14 14 14
Btk 0 0 0
NPV 0 0 0

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A mapped view of the native budworm trap captures is available at cesar’s MothTrapVisWA page. For recent native budworm field reports refer to DPIRD’s PestFax map.

The economic spray threshold levels will vary with crop type, grain price and control cost; these can be calculated for each grower’s particular situation using a simple formula outlined in DPIRD’s Management and economic thresholds for Native Budworm page.

More information on native budworm can be found at DPIRD’s;

For more information contact?Alan Lord, Technical officer,?South Perth +61 (0)8 9368 3758 or +61 (0)409 689 468.

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Article author: Alan Lord (DPIRD South Perth).

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