Coloured bars indicate peak activity periods in the adult armyworm .

Turf | Field Crops | Control | Hint | Pictures

Background

The numerous species of Armyworms in Australia are foremost pests of cereals and grasses. The name Armyworm is derived from the mass movement of caterpillars during their active and damaging periods. Armyworms are from three genera, Persectania spp., Pseudaletia spp. and Spodoptera spp . Their pest status and distribution in Australia varies between species. The principal species of Armyworm in Australia known to be pests of turfgrass are the Common armyworm ( Pseudaletia convecta), Southern armyworm (Persectania ewingii) and the Lawn armyworm (Spodoptera maurita). The Southern armyworm is the most common and widespread Armyworm species having been originally named in 1839. The least common armyworm species are the Inland armyworm (Persectania dyscrita), Day-feeding armyworm (Spodoptera exempta), Lesser armyworm (Spodoptera exigua) and the Cluster caterpillar (Spodoptera litura).

The various Armyworm adult stages (moths) and larval stages (caterpillars) are relatively similar in size but vary in colour and markings to the extent of requiring professional examination by entomologists to distinguish the species. The identity and taxonomy of Australian Armyworm genera have been studied (Common, 1954a; 1965) because of their agricultural significance. The biology of many Armyworm species is similar in Australia. Some species such as the Lawn armyworm are also known overseas.

Turf
It is the armyworm caterpillar, rather than the adult moth that causes the most damage to turfgrass. Armyworms are defoliators and will eat all parts of the exposed leaf and buds and flowers. Their numbers can reach epidemic levels, which can result in complete destruction of foliage in the affected area, and the reason for their common name; armyworm, as they move through an area like an army.

Field grown crops
Armyworms are defoliators and feed off all parts of the leaf. As their name suggests they are often found in large numbers, and as a result may completely strip plants of foliage over a large area given time and sufficient numbers. And as a result, it may limit the ability of the plant to develop and nourish itself, both biologically and via photosynthisis with the eventual result being that the plant/s may die.

Control
This product is designed for surface treatment only. Spray at dusk when pests are evident and damaging sunlight is at a minimum. Air and soil temperatures must be within the range 15-30 o C. Area to be treated should be thoroughly moistened before applying to ensure environmental conditions are favourable for the nematodes activity and survival.

Apply nematodes uniformly to ensure that each square metre receives the same amount of nematodes. Use a two-way spraying pattern, applying half of the total solution in each direction.

Apply Turfnem 2 at a rate of ten tubs per hectare apply through a boom spray with a minimum of 500 litres of water per hectare.

This nematode species is known as Steinenema carpocapsae which has a high efficacy on armyworm and therefore can be controlled a lower rate per hectare.

Hint
Armyworm larvae are foliage feeders. Immature caterpillars can skeletonize or eat small holes in the leaves. Turfgrass areas may be entirely stripped of their foliage particularly by the lawn armyworm. The larvae are inactive during the day but may be located using detection methods to confirm their presence.