Establishment pests

Lucerne flea, millipedes, slaters, slugs and false wireworms are still causing concern in many regions. 

 

Lucerne flea

Extremely damaging populations of lucerne flea (Sminthurus viridis) continue to cause problems in NSW. At Grenfell, in the Central Tablelands, lucerne flea has caused serious damage to mature lucerne and clover pastures and some neighbouring canola crops. The insects have skeletonised many of the plants, along with wild oats and capeweed. Large numbers of adults (2-3mm) were freely foraging on plants, and the dense patches of pests were moving steadily across the paddocks. An application of omethoate seemed to have minimal impact, so a respray has been organised. Growers north of Walbundrie in the NSW Riverina report that they have never seen infestations of lucerne flea reach such damaging levels as experienced this season.

Refer to PestFacts Issue No. 2 for further information on lucerne flea.

Millipedes, slaters and slugs

Millipedes and slaters may still be responsible for damage in later sown canola crops in the Lockhart area of the NSW Riverina. Cotyledons are being removed and leaves scalloped, although the damage appears to be patchy. One paddock has needed to be re-sown. Slugs are still being reported attacking chickpeas near Elmore in Victoria’s Northern Country and attacking canola north of Walbundrie in the NSW Riverina. Some crops will outgrow the feeding damage, while others have needed to be re-sown. SARDI Researcher, Michael Nash, has reported extensive losses of cereal crops to slugs in western Victoria and in southern NSW. In the Chatswood, Derrinallum and Mortlake areas of South West Victoria, a second baiting has been required across many paddocks. In NSW, monitoring for slugs has been more challenging because the soils dry out more rapidly, meaning less surface movement (and more in-furrow movement) of slugs. Further, slugs have been more difficult to control this season because of their protracted, rather than synchronous, emergence. This means longer lasting, quality baits are likely to provide better control. Refer to PestFacts Issue No. 1 and PestFacts Issue No. 3 for further information on these pests

False wireworms

False wireworm larvae, probably the southern false wireworm (Gonocephalum spp.) have been found damaging irrigated wheat south of Kerang in Victoria’s Northern Country. The long (>20mm) creamy coloured larvae, exclusively living under the soil, were eating out the plants’ root systems and stem, causing the plants to yellow and wither. Similar observations were made in canola crops on heavier soils near Pyramid Hill, in the Victorian Mallee. Overall damage was patchy, and it is likely that the crops will outgrow the feeding damage. Chemical control of southern false wireworms is not practical at this stage of crop development. Further information on false wireworms can be found here.

 

* Sources of field reports

Lachlan Caldwell – Agronomist, H.O. Rider & Sons (NSW Central Tablelands)

Terry Edis - Agronomist, Landmark (NSW Central West Slopes & Plains)

David Eksteen – Agricultural Consulting (NSW Riverina)

Heidi Gooden – Agronomist, Delta Ag (NSW Riverina)

Rebecca Hope – Agricultural Consultant, Dodgshun Medlin (Victorian Mallee)

Michael Nash – Researcher, SARDI (Adelaide)

Greg Toomey – Agronomist, Landmark (Victorian Northern Country)

Justin Whittakers – Agronomist, Landmark (NSW Riverina)