- Red legged earth mites (RLEM) – all winter crops (see the insecticide resistance management strategy for RLEM)
- Blue oat mites (BOM) – pastures, cereals, canola
- Balaustium mites – canola, cereals, lupins
- Bryobia mites – clover, canola, wheat, lupins
|Objectives||Pre-plant||Seedling emergence – Vegetative – Flowering|
|Insects and damage
More information about earth mite identification and host preferences
|Conduct risk assessment of each paddock based on;
Good quality seed (especially canola) will ensure seedlings are vigorous and reduce period of susceptibility to earth mite damage.
Make decisions about the need for seed dressing, pre-plant or post-emergence insecticide treatment. Consider multi-pest risk and insecticide strategy that ensures rotation of insecticide groups to minimise the development of resistance in target and non-target species.
|Weather conditions and time of day influence mite activity. Look for:
Mites can persist in a crop until November when they enter summer diapause. They do not cause crop loss in established crops.
|Monitor and record||Check paddock every 2-3 days for mites prior to sowing, at seedling stage and for at least first three weeks after crop emergence if mites are anticipated. Monitor longer if seedling growth is slow due to cool/wet conditions.
Inspect plants in 0.5 m of crop at 5-10 different sites. Ensure sampling covers field edges and areas of the crop at least 50 m from the edge
Record mite numbers and damage. Note: when disturbed mites drop to the ground to find shelter.
|Natural enemies||Shelterbelts and roadsides are a source of pests as well as natural enemies that may control mites in neighbouring fields.
Predatory mites, predatory beetles, spiders and ants will attack RLEM. Thrips and ladybirds attack BOM. A predatory mite, Anystis wallacei, was imported in 1965 for biological control. Where established it has caused significant mortality of RLEM. Its effectiveness is limited by its slow dispersal and inability to survive multiple cropping seasons.
|Thresholds||Accurate economic thresholds are not available. Damage is a good guide for the need to control but pest numbers can give an estimate of damage potential. It is also important to be aware of RLEM hatching conditions (i.e. approx. 2 weeks with maximum weekly temperature below 21.5ºC).
|Pesticides||Insecticide applications include:
One well-timed spring spray in pasture destined for a susceptible crop (e.g. canola) in autumn can reduce carryover RLEM numbers. TimeRite® is an information package that provides farmers with optimum spray dates to control RLEM in spring. Use Timerite® to guide spray timing. Note: this timing is only appropriate for RLEM.
|Timing of control is critical to minimising crop damage.
Pay close attention to individual pesticide labels as application rates vary with situations e.g. bare earth or post-crop/pasture emergence and with earth mite species.
|Communication||Be alert to the likelihood of insecticide resistance in your region. Record control failures.
An Area Wide Management approach to the management of insecticide resistance in RLEM could be considered in regions with insecticide resistance.
Industry publications provide up to date regional information about pest activity in crops