Pests

Argentine Stem Weevil

Argentine Stem Weevil (Hyperodes bonariensis) ASW occurs throughout New Zealand and is a major insect pest of grasses and cereals including maize. It is responsible for a substantial decrease in plant populations in some maize crops.

Damage

Maize can become infested with ASW larvae if it is sown too soon (less than four weeks) after cultivation from pasture, annual ryegrass or cereal crops, or in previously cropped ground where grass weeds, especially Poa annua, are present. Almost all ASW damage occurs during the first four weeks of maize plant growth.

Control Options

The best method of controlling ASW numbers is the implementation of a fallow period of 4-6 weeks prior to planting. It is important to note that the fallow period starts only when all vegetation, especially the grass, is completely buried.

Seed Treatment

Poncho®*
Gaucho®*

Black Beetle

Black Beetles (Heteronychus arator) are a rich brown glossy black. They are robust beetles 10-15 mm long.

Damage

Black Beetles do not occur every season but when they do, they are a very damaging pest in seedling maize with numbers as low as 1/m2 causing economic losses.

Control Options

For maize crop paddocks previously planted in maize crops, the risk of damage will be low if Black Beetle numbers are low. Before cultivation begins, check grass weeds for tiller damage. Sort through the top 100 mm of the soil under grass weeds for adult beetles. Control measures will be necessary if there are 1-2 Black Beetles per square metre. The best control is achieved through the use of Poncho®* insecticide treated maize seed.

Seed Treatment

Poncho®*
Gaucho®*

Greasy Cutworm

Greasy cutworm (Agrotis ipsilon aneituma) occurs throughout New Zealand. Numbers vary greatly from year to year. In some seasons cutworm can reach epidemic proportions, whereas in others they are rarely seen.

Damage

Maize seedlings are most vulnerable up to the four leaf stage. Damage often begins before seedling emergence.

Control Options

Weedy patches allow caterpillars to survive and carryover until the maize crop emerges. Where possible, a 5-6 week weed-free fallow period should be achieved before planting. The caterpillars die from starvation and desiccation. Consider using Poncho®* insecticide seed treatment for the control of greasy cutworm in maize. Poncho®* has a withholding period of 42 days.

Seed Treatment

Poncho®*

Birds

Birds (including pheasants, pukekos & ducks) found around maize paddocks.

Damage

Maize seed is most vulnerable from planting through until the 4-5 leaf stage. Birds either dig for the seed or pull the young seedling out and eat the seed.

Control Options

Mesurol®* treated seed.

Seed Treatment

Mesurol®*

*Registered trademark of the Bayer Group.