Lawns in many areas of Australia are being attacked by armyworms (Spodoptera mauritia). These caterpillars are brown, greenish brown or black, sometimes with striped or triangular markings along the body. They feed on lawns in large groups then when the food supply is exhausted they move off together, a bit like an army on the march.
Particularly affected are kikuyu and couch lawns. Less affected are buffalo and Queensland blue couch. Corn may also be attacked.
If you notice that your lawn has been eaten almost back to bare soil, spray with a fast-acting insecticide such Baythroid Lawn Grub & Garden Insecticide (which has low toxicity to birds). Follow the instructions on the container. The bad news is, that it is possible for lawns to be attacked several times during summer and early autumn.
If this happens, retreat with insecticide. As the roots of the lawn should still be intact despite the damage to the leaf area, it is possible to get regrowth by applying a fast-acting fertiliser such as Thrive Soluble Lawn Food (use the hose on style pack) or Shirley’s No 17. Water lawns well after applying dry fertiliser. Follow up in spring with a slow release complete lawn food such as Scott’s Lawn Builder.
Armyworm is found in the warmer months and can be encountered in most areas of Australia. Populations should be decreasing now, particularly in coastal NSW where it has been extremely active this summer.
Fungal problems
Recently, high humidity and heavy rainfall in many areas of Australia have made plants in the protea family, such as banksias, proteas and grevilleas, very vulnerable to root rot. Citrus, avocados and other ornamentals are also at risk. Don recommended spraying these plants with Yates Anti Rot over the foliage as a preventative measure.
Further information
Baythroid Lawn Grub & Garden Insecticide $16.95
Thrive Soluble Lawn Food (Hose On Pack) $14.95
Scott’s Lawn Builder $10.95
Yates Anti Rot $12 (500ml)
All of the above products are available at most nurseries and hardware stores.