Grubs in winter cereals are not unusual at this time of year, and already there have been reports of high numbers (up to 20/m2) in Central Queensland wheat (Figure 1). More grubs can be expected in southern districts as the season warms up. The two most likely larvae (grubs) found in winter cereals are the corn earworm, Helicoverpa armigera, and… Read more »
Cereal aphid numbers have increased rapidly over the past 3 weeks as the temperatures have increased. Whilst low numbers of aphids have been present in many crops (wheat and barley) for some time, it was not until a couple of weeks ago that numbers reached levels of concern to agronomists and growers. Until the last few seasons, cereal aphids have… Read more »
David Murray, Toowoomba Farm hygiene is an important component of integrated pest management (IPM), particularly when it comes to managing pests such as cotton aphids and Cotton Bunchy Top (CBT) disease. Recent surveys of cotton-growing areas indicate the presence of aphids and CBT, and wetter conditions through the coming winter could favour the growth of weeds that are… Read more »
In the last week, reports from the Downs are suggesting that silverleaf whitefly (SLW) numbers have increased rapidly, and now there are a number of fields that have a population at or exceeding the treatment threshold. This posting has been compiled from information and discussion with Richard Sequeira (Principal Entomologist, Emerald) and Paul Grundy (Senior Entomologist, Ayr) who have considerable… Read more »
Reports of increasing numbers of whitefly are filtering in from across the Downs. In some cases, numbers are sufficient to suggest that control of Silverleaf Whitefly (SLW) may be warranted. Correct identification and regular monitoring of populations is essential to determine if intervention is necessary. Which whiteflies are out there? Results of whitefly samples identified from Downs cotton crops… Read more »
There is an increasing number of reports of whitefly in cotton crops on the Downs. Typically, whitefly start appearing in crops in mid to late summer, once populations have built up on weed hosts or other host crops (e.g. sunflower) adjacent to cotton crops.So far this season we have been able to make collections of whitefly adults and immatures (scale)… Read more »
As many of the early sorghum crops reach physiological maturity, and approach harvest, questions are being asked as to whether it is necessary to control large populations of nymphs in these crops. More specifically, whether these RGB will cause any damage to the maturing grain between physiological maturity and harvest. Photo: Dave Murray (BigBug) out looking at a sorghum… Read more »
Adam Hardy Senior Entomologist, Queensland Department of Primary Industries and Fisheries, Toowoomba. Photo: Adam Hardy (right) and Bernie Franzmann inspecting midge rating trials. Over the last decade sorghum midge have not caused many headaches for sorghum growers. However, staggered sorghum plantings mean that sorghum midge are likely to be found building up in numbers in later planted sorghum… Read more »
Rutherglen bug infestations of grain sorghum This season we are seeing large infestations of Rutherglen bug (Nysius vinitor) (RGB) in sorghum crops from Central Queensland to the Downs, and further south. The large infestations are most likely a result of storm activity and the growth of weed hosts on which they breed up. RGB are very mobile, with large numbers… Read more »
Some issues have recently been raised on the Darling Downs regarding the use of Helicoverpa nucleopolyhedrovirus (NPV) against corn earworm on grain sorghum. These issues involve the delay in time to kill and the level of control not necessarily meeting growers’ expectations. Seasonal conditions The last couple of weeks on the Downs have been cooler than normal. The average daily… Read more »
