Category Archives: helicoverpa

Refresher on managing helicoverpa in chickpea

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With the approach of spring, helicoverpa start to become active. In CQ, chickpea crops are attractive to moths, and it is timely to revisit some of the key points related to making decisions about control of this pest in crops.In this article, I wanted to discuss a couple of the recommendations which some growers and agronomists have found a bit… Read more »

Latest helicoverpa thresholds for mungbeans

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Revised thresholds for helicoverpa in flowering/podding mungbeans are based on a rate of damage of 35 kg/ha per larva per square metre in podding crops. The new thresholds are nearly double the old threshold of 1/m2, and make allowances for variations in control costs and crop value. For a typical scenario with pesticide control (including aerial application) costing $40/ha and… Read more »

New Helicoverpa thresholds in vegetative soybeans

The new economic threshold for Helicoverpa in vegetative soybeans is 8 larvae per sqare metre and replaces the old 33% defoliation threshold. The new threshold is based on field trials conducted by John Rogers (formerly with DPI&F at Kingaroy). These field trials show that approximately 7.5 larvae per square metre can be tolerated with no yield loss, but that severe… Read more »

Bring on NPV against grubs on grain sorghum

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Every year caterpillars of the corn earworm (helicoverpa), Helicoverpa armigera, cause losses to sorghum crops. Regular inspection during flowering is important to detect caterpillar infestations and properly time control measures. Pre-flowering heads of grain sorghum are very attractive to egg-laying moths of the corn earworm. On any individual head, most eggs are laid prior to the start of flowering, as… Read more »

Managing Helicoverpa larvae in chickpea crops close to dessication and harvest.

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Over the last week or so we have received a number of enquiries about how best to manage new egg-lays, and populations of small larvae, in chickpea crops that are close to dessication and senescing. Of most concern are crops that still have reasonable areas of green crop in them, and what the likelihood of damage is if the weather… Read more »

Helicoverpa management in chickpea – a refresher

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A comprehensive overview of Helicoverpa management in chickpea can be found in the DPI&F brochure Helicoverpa management in chickpea (2007). You can read or download a copy of the brochure at the DPI & F website at www.dpi.qld.gov.au/fieldcrops. Click on the link to Helicoverpa management in chickpea where you will find the brochure. Key management decisions The following is an… Read more »

What are those grubs in winter cereals?

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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 »

Diapause tool to identify helicoverpa risk

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While there was a hefty presence of corn earworn or cotton bollworm, Helicoverpa armigera, in the early and middle part of the 2007-08 season, pest activity has declined in recent weeks and for the most part they appear to pose no major risk. What is diapause? This is the time of the year when a proportion of mature larvae going… Read more »

Getting the most from NPV sprays on grain sorghum

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 »

Friendly fighter conquers foe

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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 »