Yellow-winged locusts (Gastrimargus musicus) are native insects, distinguished by bright yellow wings, they are 35-50mm in length when mature and make a distinctive clicking noise when flying. Adult swarms of yellow-winged locusts are infrequent and generally localised. High densities can cause significant damage to green plants, in particular green grass.
Description of adult
- Bright yellow hind wing with a marginal dark brown or black band.
- Makes a distinctive clicking noise when flying.
- In the solitary phase populations are predominantly green but when in the gregarious phase. (swarming) populations are predominantly brown.
- Males are 25 to 35 mm, females are 35 to 50 mm in length.
[1]Adult yellow-winged locust, note the yellow spot with black stripe on the hind wing. This is a distinctive feature of this species.
Description of nymph
- In profile the thorax is domed well above the head.
- Hind femur (thigh) is banded.
- General body is grey-black in colour.
[2]Lateral and dorsal view of yellow-winged locust nymph, note the arched (domed) thorax in the lateral view, the hind femur (thigh) is banded and dark knob on the wing bud segment in the dorsal view. Image copyright NSW Department of Primary Industries.
Habitat
Prefers moist coastal and sub-coastal regions and is commonly found in the tropics and sub-tropics.
Found in association with a variety of grasses, both native and introduced. It is common in the rangelands, pastures, lawns and in parks.
Life cycle
- In temperate regions this locust has one generation but can have up to three generations in tropical regions.
- Egg pods are laid on bare, compact soil, especially in overgrazed pastures.
- In tropical regions:
- Eggs hatch after 17 days, producing nymphs.
- Nymphs take 40-50 days to become immature adults.
- Immature adults take a further 12-14 days to mature and lay eggs.
- Adults are usually noticed from September to April.
- At high population densities, nymph bands and adult swarms can form.
- Adult swarms are infrequent, localised and spread slowly.
- As the dry season starts, numbers of locusts will decrease.
Control considerations
- Control should only be considered to protect high value crops.
- Control of yellow-winged locust is the responsibility of the landholder.
- This locust species is not declared in Western Australia.
- Nymph bands can be sprayed with boom sprays, this is the most effective control method.
- Spraying in the late afternoon is more effective, as nymphs tend to spread out during the day.
- Dense, high pasture or crops should not be sprayed in still conditions, as wind turbulence is needed for spray to penetrate foliage.
- Nymphs die after contact with, or ingestion of, treated vegetation within 2-48 hours after spraying. Follow-up treatments may be necessary for up to 2 weeks after spraying, as not all eggs hatch at the same time.
- Once locusts are flying, aerial spraying of agricultural chemicals is the only efficient control method. However, locusts can migrate back into sprayed areas.
Chemical control options
- Landholders are reminded to comply with label regulations, particularly the withholding periods for grazing and export intervals. Label withholding periods only apply to domestic markets; refer to SafeMeat [3] for export withholding period (EAFIs, ESIs and EGIs [4]).
- Fenitrothion has a registration for yellow-winged locust control at 200-300 mL/ha.
- Use of permitted chemicals is restricted to crops for which there are current registrations for other pests. Chemicals registered for spur-throated locust and Australian plague locust will also have efficacy on yellow-winged locust nymphs. However, rates of application must not exceed the label rate for each crop.
See Also
Links
SAFEMEAT [3]