Microplitis demolitor is just one of many friendly fighters that battle to contain numbers of one of our most important pests, the corn earworm, Helicoverpa armigera. Corn earworm on grain sorghum is making its presence felt and many crops are being sprayed with Helicoverpa nucleopolyhedrovirus (NPV) to control above-threshold infestations of caterpillars. The current high value of grain sorghum (over… Read more »
Sorghum growers across the Darling Downs can expect to see an influx of the corn earworm, Helicoverpa armigera, in their flowering sorghum crops over the next few weeks. Growers are well equipped to deal with the problem in an environmentally friendly way. Moths are active and wanting to lay eggs on susceptible crops, and sorghum crops putting up heads are… Read more »
Corn earworm larvae on vegetative sorghum crops produce characteristic holes in the leaves after feeding in the throat of the plant. These tell-tale signs are of no great concern as this type of feeding will not affect crop yield. The recent presence of high numbers of corn earworm, Helicoverpa armigera, on winter cereals and chickpea could herald the beginning of… Read more »
Both Helicoverpa armigera and armyworm larvae are occurring together in wheat and barley. It is important to be able to separate the helicoverpa larvae from the armyworm larvae in order to determine whether the numbers are above or below threshold, and, if needed, to make the most appropriate decision about control options. Armyworm larvae have three white stripes on… Read more »
Control considerations – which product when? There is a range of products registered for helicoverpa control in chickpea. However, the use of synthetic pyrethroids is really only an option in regions where H. punctigera dominates, or where the population is predominantly made up of larvae smaller than 5 mm in length. The use of SPs against a predominantly H. armigera… Read more »
Corn earworm, Helicoverpa armigera, are frequently found in winter cereals but usually numbers are too low to warrant control. Occasionally, however, corn earworm numbers may be sufficient to cause economic damage. The high value of today’s grain is further reason to carefully check for grub infestations. It is not unusual to find both corn earworm and armyworm in cereal crops…. Read more »
With the current high value of barley, growers should closely monitor armyworm infestations as crops approach maturity. Armyworms are important pests in southern Queensland where they attack winter cereals, particularly barley and oats, in September and October. Larvae appear in plague proportions in some years, and are patchy in others. Head cutting by large larvae can lead to serious losses… Read more »
Making decisions about control of Cereal Aphids This post is an update on cereal aphid management following a number of enquiries from growers and agronomists over the last week or so. Which species in crops? There are two species of aphid you are most likely to encounter in winter cereals (oats, wheat and barley). They are the oat aphid (Rhopalosiphum… Read more »
Aphid control decisions tend to be more problematic in moisture stressed winter cereal crops, since in a well supplied crop the level of moisture extracted from the crop by aphids is of little concern. However, in dry times every drop seems precious. Had we not received the recent rain over the last few days throughout southern Queensland and northern NSW… Read more »
On Friday August 10, St George growers and agronomists met to discuss strategies to manage the Silverleaf whitefly population in the irrigation area. Over the past two seasons, a number of cotton fields in St George have been treated for SLW. Last year more fields were treated earlier, and required a second treatment. It is clear that SLW is now… Read more »
