The 2013/14 soybean growing season has been challenging for many growers with very low rainfall and high temperatures until late March. Crop stress was sometimes wrongly attributed to insect pests although a number of crops were infested with more unusual pests such as etiella. The high temperatures also increased the impact of lucerne crown borer in infested crops.
On the Darling Downs there have been a number of reports of common armyworm causing significant defoliation in sorghum, corn and millet. Jimbour grower John Alexander treated a severely defoliated sorghum crop two weeks ago. Millet and corn crops in the same area have also been affected. Although patchy, the outbreaks have the potential to cause significant yield loss if… Read more »
Background: Significant etiella outbreaks have recently been reported in soybeans and mungbeans on the Darling Downs, in the South Burnett (SE Qld) and in the Moree and NorthernRivers regions of NSW. In some soybean crops on the Downs, 100% of plants were infested and 72% of axilliary buds damaged to varying degrees. These outbreaks are similar but more widespread than… Read more »
Following the recent detection of symphyla in some cotton fields on the Darling Downs, DAFF Entomology have been testing sampling strategies for this potential pest of cotton. Literature for a similar symphyla species in North America suggested that baiting with potatoes may be an effective strategy for assessing symphyla abundance and whether individuals were actively feeding or in a restive… Read more »
There have been a number of reports of mirid infestation in cotton on the Central Highlands and at St George. Recent research has focused on the development of plant-based thresholds that should make it easier to make decisions about mirid control.
An investigation into poor establishment in a field of cotton west of Dalby this week confirmed the presence of the soil dwelling symphyla as the likely cause. Symphylans are relatively common in most soils where they generally feed on decomposing organic matter. Symphyla as crop pests Symphyla have caused problems with crop establishment for a number of seasons in the… Read more »
Rutherglen bug (RGB) are best known for the damage they can cause in sunflower and sorghum during grainfill, but they can also damage and even kill seedlings when present in large numbers. In 2012 RGB damaged establishing spring crops in areas of southern and northern NSW. This spring, in some crops there are large numbers of RGB in the canola… Read more »
Armyworm in barley and wheat. A number of reports of armyworm in crops have been received over the past couple of weeks. Numbers range from 30 to 50 per square metre (extreme) to a more typical 5 to10 larvae per square metre. Assessing larval density is done using a sweep net, bucket or beating a section of row into a… Read more »
DAFF Queensland entomologists have confirmed a small outbreak of Solenopsis mealybug (Phenacoccus solenopsis) on a cotton property west of Dalby on the Darling Downs. This is the same species of mealybug that affected cotton crops in Emerald and the Burdekin in 2010 and more recently in the South Burnett.
Etiella (Etiella behrii) larvae have been observed in significant numbers (up to 10 larvae per square metre) in vegetative soybean crops in the Cecil Plains/ Pampas regions of the Darling Downs, and in low numbers (<1/sqm) in a DAFF soybean trial at Kingaroy. These infestations are likely due to the current hot and dry seasonal conditions which historically favour increased… Read more »
