Army worms on the march

Army worm caterpillars are on the march, and munching through newly sown pastures in the Bay of Plenty.

Bill Webb of Bill Webb Feed Solutions says paddocks turned back into pasture after maize harvest and Lucerne stands have been attacked, and he's warning other farmers to check their pasture and forage crops.


Army worm caterpillars can damage both pasture and forage crops.

'So far we've had to spry more than 100 ha to control the worms,” says Bill.

All new pastures can be at risk from the caterpillars – and given the right conditions there can be a population explosion, says Bill.

AgResearch advises insecticides, applied at first sign of caterpillars and damage, remain the most effective way to control tropical armyworm.

Farmers will be hoping for cooler winter temperatures should reduce numbers, but in the meantime should consult their pesticide representatives for advice on what sprays are best to use.

The name army worm comes from the way the caterpillars ‘march' across a field in formation, eating all suitable plant material in their path.

Colours vary and caterpillars grow up to 50mm long.

During summer eggs hatch within a week and the caterpillars take about three-four weeks to fully develop. The pupal stage lasts about two weeks and the female moth begins laying eggs about four days after it emerges from the pupa.

Several generations occur during spring-autumn, depending on the average temperature; the exact number is not known.

There are two types of caterpillar which can cause this kind of crop damage; tropical armyworm (Spodoptera litura) and cosmopolitan armyworm (Mythimna separata).

Tropical armyworm is widely distributed through Asia and the Pacific regions.

Cosmopolitan armyworm is found in warmer parts of the North Island, causing sporadic damage in Northland, Waikato, Bay of Plenty, Taranaki and Manawatu region.

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2 comments

ME TINKS

Posted on 22-04-2016 17:02 | By old trucker

we could use these in their millions to put tunnel in for bypass.


Ooooh

Posted on 22-04-2016 21:15 | By overit

Gross. And more sprays to pollute the land. Another epidemic like the invasive grass that's come in on palm kernel around the country.? Globalism is scarey stuff especially with our Border Control.


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