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Lookout for other invertebrate pests

Lucerne Flea hatch following periods of good soaking winter rains. 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 exacerbated 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.

Cut worms 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 from emergence through establishment at the base of plants; damage is often patchy.

African Black Beetles are often a sporadic pest of perennial grasses and cereals in autumn/early winter. John Sykes (John Sykes Rural Consulting) has had several unconfirmed reports of African Black Beetle damage to rye grass in the Upper Murray. The adult beetles chew plants at or just beneath ground level, ‘ring-barking’ or chewing right through the stem. Look for damage symptoms and the presence of adults.

Wheat Curl Mites and Wheat Streak Mosaic Virus (WSMV) had a significant economic impact on the wheat industry in much of the high rainfall zone of NSW last season. WSMV symptoms are green streaks on the leaves which later develop into yellow stripes running parallel to the leaf veins. WSMV is spread by a tiny (0.3mm) cigar shaped mite, the wheat curl mite (WCM), which is not visible without the aid of high powered magnification.  A recent survey conducted by cesar in NSW has identified numerous alternate non-wheat host plants for the WCM which allows survival between seasons. Initial findings indicate control of weeds and grasses within and nearby wheat crops could curtail the spread and build up of WCM during and between seasons. WSMV infection was most severe in early sown graze/grain crops in NSW last season. This could mean that delaying sowing time of crops may reduce the risk of infection (as in America), however the WSMV was not restricted to such crops, and further research is needed to determine the most appropriate control strategies.

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