PestFacts Issue 8, 2019
In this issue
- Aphid activity and monitoring guidelines
- Etiella flights expected to occur
- Spring control of redlegged earth mite
- Spring clean storage equipment to avoid grain insect activity
Etiella flights expected to occur
The SARDI degree-day model predicts the timing of initial spring Etiella flight activity using local daily maximum and minimum temperatures from June 21 onwards. Crop monitoring should commence before the cumulative total of degree-days (base 10°C) first reaches 351 (approx. 10% into peak flights). Ideally, start monitoring 1-2 weeks earlier than this figure (around 300). As a guide, daily maximum temperatures of 25°C would see cumulative degree-days increase from 300 to 351 in about 7 days.
Model predictions for degree-day accumulations based on current temperatures (to 23 Sept 2019) indicate that growers near Cleve, Cummins, Kadina and Roseworthy should commence monitoring immediately:
- Cleve, SA: 355*
- Cummins, SA: 328
- Kadina, SA: 334
- Roseworthy, SA: 328
- Lameroo, SA: 269
- Keith, SA: 282
- Horsham, Vic: 231
*Once the model has hit 351 it no longer needs to be run.
To run the model yourself, download the SARDI Etiella degree-day model (XLSX 23.7 KB). Temperature data for your local region can be obtained from the Australian Bureau of Meteorology website and must be entered into the model from 21st June onwards.
Monitoring for Etiella moths
To monitor, use a sweep net and take samples of 20 sweeps in at least 5 locations. If moth numbers exceed threshold guidelines of 1-2 moths per 20 sweeps, consider immediate treatment with a registered insecticide. Commence re-monitoring from 7-10 days after treatment. SARDI entomologists scouting at Wandearah East have not yet seen high activity.
What to look for:
- Etiella moths are 10-15 mm long
- greyish-brown in colour with a pale white stripe running along the front edge of the forewings
- a prominent `beak` protruding forward from the head
- eggs are laid on the calyx, are clear in colour and change to orange prior to hatching.