While drought has dashed the planned rotations of many growers, there is still a risk of pest outbreaks at this time of year. Below are some of the most common to keep an eye out for. A note on withholding periods following insecticide use in crops that are diverted to stock If insecticide treatments have been applied to crops which… Read more »
Armyworm infestations of barley crops, in particular, are being reported from southern NSW to the Darling Downs. Large numbers of moths are also being seen around lights at night. It is not unexpected that armyworm would be abundant this spring as some of their source areas (Channel Country, North Western Queensland) would have received significant rainfall or flows earlier in… Read more »
Outbreaks of Bruchidius mackenziei (unofficially called the soybean bruchid) have been reported recently in soybean crops in the South Burnett and North Queensland. The bruchids were detected at harvest and postharvest, their timing matching previous reports of this pest from the Darling Downs and Burnett in 2009/10. Bruchidius mackenziei is a native bruchid that is most likely not a true… Read more »
Green lacewing larvae are generalist predators, and are important natural enemies of a range of pests including aphids, helicoverpa, whitefly and mealybugs. There are many species of green lacewings in Australia, including some that commonly occur in field crops. Readers are most likely to be familiar with Mallada signatus, which regularly features in ID guides, but another species, Plesiochyrsa ramburi… Read more »
After the introduction of Bt cotton in the 1990s, the focus of cotton pest management has shifted to sucking pests. Green and brown mirid (Creontiades spp.) damage can occur at any stage, from seedling to boll filling, although crops are usually attacked before peak flowering. Feeding damage (including terminal death, abscission of young squares and bolls, and lint damage in… Read more »
Significant soybean moth flights have been observed recently in some coastal Burnett soybean crops. Little damage has been observed to date, but high numbers of adult moths are an early warning sign of potential severe defoliation. Soybean moth is usually a minor soybean pest but in spasmodic major outbreaks, larval populations can exceed 1,000 per square metre. Identification Soybean moths… Read more »
Significant soybean aphid (Aphis glycines) populations have now been observed in many coastal soybean crops. Once the crop approaches late flowering, a spray decision must be made as later aphid infestations can severely delay harvest maturity. Careful monitoring is required to determine if populations are trending upwards to and beyond threshold levels, or if the aphids are being contained by… Read more »
Peanut mite (Paraplonobia sp.) outbreaks have been widely reported in Burnett peanut crops from Kingaroy to Coulston Lakes. This is not surprising as these mites are favoured by prolonged hot dry weather as has been experienced lately. The first sign that these mites are present are plants with pale leaves. On closer inspection, fine feeding stipples are evident on the… Read more »
With cotton crops approaching cut-out, it’s time to make critical decisions regarding silverleaf whitefly (SLW) management. Recent hot weather has seen SLW numbers increase in many areas—indicating that a number of fields are likely to require control action soon. SLW has evolved to become one of the most complex insects to manage in a cotton system because we are essentially controlling… Read more »
A major outbreak of grass blue butterfly (GBB) (Zizina labradus) in late vegetative and flowering soybeans has been reported in the Maryborough/Hervey Bay region. Some crops inspected had 10-12 GBB larvae per square metre with many plants denuded of buds and flowers. Other crops had less damage and fewer larvae (4-5 per square metre), but had 5 or more adult butterflies… Read more »
