The quick finish for winter cereals this season has resulted in the majority of crops escaping infestations of armyworm. Headers are already into some fields, but there are reports of armyworm making their presence felt in some of the later crops.
Being aware of their presence is one thing; whether to intervene is another.
In some late crops starting to turn, the presence of up to 12 small armyworm larvae per square metre need not necessarily sound alarm bells. This situation requires careful and regular monitoring, but there is every chance the crop will make it to harvest without the need to control armyworm.
If however, the crop lingers and the armyworm develop into medium and large larvae, there is a risk, particularly with barley, that head cutting will result in high yield losses. In this situation, quick action may be required to control armyworm and prevent losses.
The key points are
1) to be aware that armyworm are present and
2) to inspect regularly as the crop approaches maturity so that appropriate action can be taken if head cutting occurs.
For more information on armyworm, see the posting made on 20 October 2008.
Photo: Watch for the early signs of head cutting.
Reminder: Last date for Steward® EC use on chickpeas is 15 October
Winter pulses have had their expected share of helicoverpa infestations over recent weeks and most crops have been sprayed to control grubs. Strategies to minimise the risk of insecticide resistance are available. The following points should be observed.
Under the Insecticide Resistance Management Strategy (IRMS), the last use of Steward® EC for Central and Southern regions is 15 October, while the last use date for Northern (Central Queensland) regions (15 September) has long passed.
Grower and consultants are also reminded that for all pulse crops, not more than one application of Steward® EC per field is allowed for the crops entire growth cycle.
Access the full IRMS for 2009-10 on the Cotton CRC website: