Lucerne flea hatch following periods of good soaking autumn-winter rainfall. Due to the requirements of their eggs, they are generally a problem in regions with loam/clay soils. Keep a good look out in paddocks of seedling lupins, canola and young clover. If spraying is required, do not use synthetic pyrethroids. In crops, spot spraying is generally all that is required; do not blanket spray unless the infestation warrants it.
Aphids can be problematic to emerging crops and grasses at this time of year. The importance of many aphid species is heightened by their ability to act as vectors for important plant viruses and diseases. Aphids that arrive in crops in autumn and persist in low numbers over winter may lead to large, damaging populations that peak in late winter and early spring. However, in most years natural control by predators and parasites and adverse weather conditions keep their numbers below economic spray thresholds.
Slugs are stimulated out of their summer aestivation following autumn rains, generally in paddocks were they have previously been a problem. Although all seedling crops and pastures may be attacked, canola is particularly susceptible. Slug numbers can be monitored by placing tiles or flowerpots on the soil surface and counting the number under them after a few days.
Cutworms can be a problem to all germinating crops. Prolonged autumn green feed in areas may allow them to develop to a large size by the time crops start emerging. Check crops, especially pulses and pasture legumes, from emergence through to establishment at the base of plants; damage is often patchy.
Bryobia Mites are most active in warm conditions in autumn, spring and summer. They attack clovers, lucerne, lupins and canola, and are likely to be active in many regions. The feeding damage is characterised by a long trail of whitish-grey spots on the upper side of cotyledons and leaves.