What’s bugging your lawn?

To get your lawn looking it’s best it’s mostly about getting the fundamentals right; correct watering, feeding and mowing technique, plus good drainage and enough sunlight. However, there are a few pests and diseases to watch out for so let’s run through the most common ones and their organic solutions.

Curl grubs

Found in the soil these fat, white grubs curl into a ‘C’ shape when exposed, hence their common name. They are the larval stage of various beetles; some are native like Christmas beetles and some are introduced like the African black beetle. In grub form it’s hard to tell them apart. The grubs feed on decaying organic matter and plant roots. Some of the adult beetles also eat grass blades but most of the damage is caused by the larvae feeding on roots. Finding a few grubs here or there isn’t a worry and is just part of a natural ecosystem. However, in high numbers dead patches can develop, usually during the warmer months, and they slowly expand. Grass looks dry despite the soil being moist and will pull away easily (thanks to the lack of roots).

Organic control: If treatment is required drench the soil with neem or beneficial nematodes.

Armyworm

Despite the common name this is not a worm but a type of caterpillar; a very hungry caterpillar that grows up to 5cm long. It’s typically a mix of dull-grey, green and brown colours with some stripes and dots. Usually armyworm appear in groups and feed at night on the soft grass blades, leaving thicker stems untouched. The damage is fast and severe, often in a straight line, like an advancing army. During the day they’re hidden in the thatch so you won’t see them. A lawn that suddenly looks stripped means you’ve got armyworm. You can confirm their presence by pouring a bucket of soapy water at the edge of the damage. They’ll quickly wriggle out of hiding as they hate the soap. Lawn armyworm is a warm-season pest with the adult moth laying eggs from spring to autumn.

Organic control: Spray infested lawns with neem or beneficial nematodes. High numbers of other types of caterpillars, like cutworm and sod webworms, may do similar damage and can be controlled with neem.

Mites

There are several mites that attack lawns but they’re very small so instead of seeing the pest you’ll only see their damage. Couch mites result in distorted bunchy growth called ‘witches’ brooms’. Grasswebbing mites cause silvering of grass blades that expands into a large ‘bleached’ area. They also create very fine pale webbing. Two-spotted mites can cause similar damage. Mites generally attack warm season grasses, like buffalo, couch and kikuyu, and enjoy dry conditions.

Organic control: Treat with wettable sulphur.

NOTE: When spraying sulphur mix, go over the lawn a couple of times to ensure good coverage.

Pick up Issue 168 of ABC Organic Gardener in stores now to read the rest of this story on common lawn pests and diseases, or subscribe at mymagazines.com.au to get every issue delivered straight to your door.