Pests of Emerging Crops

Favourable moisture and high stubble loads have the potential to harbour invertebrate pests. Predation on newly emerging crops can cause severe damage, especially to canola and legume pastures.

Following are pests of significance that may be present during sowing and early emergence.

Red Legged Earth Mite (RLEM)

–     Small black mites with distinctive red legs

–     Most damaging to newly emerged seedlings of canola and legumes

–     Prevalent following the autumn break when temperatures fall below 20˚C

–     Sucking damage causes thickening and silvering of the leaf

–     Dimethoate and Le-mat are registered for control

–     Application rate of Dimethoate is 85 ml/ha

Blue Oat Mite (BOM)

–     Similar appearance to RLEM, but with a red spot in the middle of the back

–     Similar damage, emergence patterns and control measures to RLEM, but can be harder to control

–     Application rate of Dimethoate is 90

Lucerne Flea

–     Small light green member of the springtail family

–     Emerge following the autumn break and can affect cereals, pulses, canola and pasture species

–     Symptoms include window-like holes created by chewing of the underside of leaves

–     Dimethoate and Le-mat are registered for control

–     Application rate of Dimethoate is 55 – 85 ml/ha

Earwigs

–     Damage canola seedlings through chewing of young leaves, often whole plants will be eaten leaving only the small plant stem

–     Most problems associated with heavy stubble patches or adjacent to pastures and tree lines.

–     Important to distinguish between European earwigs which are a pest and Native earwigs which are beneficial.

–     Control by spreading 5 kg/ha cracked wheat, soaked in 200 ml Lorsban + 250 ml sunflower oil.

Weevils

–     3 – 5 mm long, dull grey/brown and rounded appearance

–     Can cause feeding damage in a range of crops, though canola is most severely affected.

–     Damage is often adjacent to pasture paddocks and tree lines.

–     Damage takes the form of ‘ring barking’ just above ground level, leading to death of the young plant. In some cases entire seedlings are eaten.

–     Most feeding occurs during the night, making daytime identification difficult.

–     Fastac Duo is registered for control.

–     Application rate of Fastac Duo is 400 ml/ha.

Slugs

–     Damage establishing canola and pastures.

–     Problems associated with slugs are likely to recur in similar areas, given adequate moisture and cover

–     Symptoms include irregular chewing marks on leaves or bare areas developing within the paddock.

–     Slugs are most active at night and during periods of rain.

–     Baiting with Metaldehyde baits is the main control method.

–     Application rates for Meta Slug & Snail start at 5 kg/ha