Plague locust control for the home gardener and nursery areas

The impact of locust swarms on parks and gardens

Plague locusts may impact on towns as well as rural areas. As a result, many home owners are concerned about potential damage to gardens and houses, as well as effects on pets.

Generally, the adult or winged locust (shown at right) will fly in as a swarm. Often the swarms are not dense enough or of sufficient size for effective control by spraying with insecticides. In other cases, strict pesticide protocols prevent large-scale spraying in proximity to dwellings, water supplies or other environmentally sensitive areas.

Nevertheless many home owners, nurseries and park managers are concerned to protect their plants. In general, it is most difficult to totally protect plants in these situations, as locusts may fly in, eat varying amounts and then move on. The same area may be reinvaded by new migrations every few weeks.

Non-chemical methods of control

Home owners should consider the following non-chemical methods of controlling locusts:

• Valuable shrubs and plantings can be protected with insect mesh or shadecloth — this must not be green-coloured, as locusts are attracted to green areas.
• Small numbers of locusts may best be controlled by catching and squashing them.

Emergency permits for control with pesticides

Emergency permits have been issued from the APVMA (Australian Pesticides & Veterinary Medicines Authority) for locust control with pesticides. Directions for using the insecticides malathion or imidacloprid are included on the permits. These insecticides are commonly used to control other pests in the home garden, and should be readily available from your local home garden supplier.

You must obtain a copy of the APVMA permits before you spray. Current permits are available from the NSW DPI website or the APVMA portal.

Alternatively, obtain copies of AVPMA permits from Local Land Services.

Important information if you decide to spray

It is a legal requirement that you obtain a copy of the permit and read it before you spray. The Pesticides Act 1999 is enforced by the NSW Environmental Protection Authority.

Home gardeners are reminded to read the labels of the products they use, as well as the permit. Again, this is a requirement of the Pesticides Act.

Be sure to:

• wear the personal protective equipment specified on the label;
• if only shrubs and garden beds are to be sprayed, keep children and pets out of the garden while spraying and until the spray has dried;
• if the lawn is to be sprayed, restrict access to the whole garden for 12 hours;
• avoid spraying the pesticide over any water in the home garden, such as ornamental ponds, swimming pools and water for pets;
• avoid spraying in windy conditions when the spray might drift over the fence onto a neighbour's property;
• avoid smoking while spraying;
• wash your hands and any exposed skin with warm soapy water immediately after spraying;
• store the pesticide in a locked place out of the reach of children (dimethoate and malathion are both scheduled poisons);
• dispose of any unused mixed-up chemical according to the advice on the label;
• check the withholding period, and do not harvest vegetables or fruit crops within this time.

Calibrating knapsack and hand held sprayers

The product label will recommend the amount of pesticide that needs to be applied to kill the locusts. The product label may also recommend an amount of water to mix with the pesticide.

To ensure you are applying the correct amount of pesticide and water, the output of the sprayer needs to be measured. The process of measuring the output is called calibration.  It is illegal to apply more pesticide than the label recommends.

Applying more pesticide than the label recommends also wastes money and can cause unacceptable residues in fruit and vegetables. Applying less pesticide than the label recommends is likely to result in a spray failure, because the locusts will not get enough pesticide to kill them.