Pests, Weeds & Diseases

Common Lawn Weeds

There are two types of weeds: broadleaf weeds and narrow-leafed weeds (grass weeds).

Broadleaf weeds are the most common problem. These include burrs, pig weeds, sensitive weed. Generally, anything that is not a grass is a broadleaf weed. You can determine grass because it has leaves that are basically the same width at the bottom and the top.

Broadleaf Weeds

Purchase a broadleaf weedkiller from a garden shop. They may have different names but the active ingredients should be MCPA and Dicamba. Do not use a broadleaf weedkiller with Dicamba in it on Buffalo grasses. Make sure your grass weeds are growing well. This may mean fertilising them a couple of weeks before spraying, mowing them 4 to 5 days before spraying, and watering them the day before you spray.

Generally, it is best to spray in the morning after the dew has gone and do not spray if rain is expected within 4 hours. You can spot spray the weeds or spray the whole area. Remember most of your garden plants are broad leaved so avoid spray drift. Usually you will see weeds start to brown off in a week. Do not mow for a week after spraying.

Narrow Leaf Weeds

Grass weeds are a bit harder to control but they aren’t as unsightly. The decision here is whether or not to bother getting rid of them. In grasses such as Tropika, they do not stand out.

In hybrid/green couches, such as Winter Green, Greenleas Park, and Legend, you can buy sprays that will kill most grass weeds without affecting the lawn, but they are expensive and sometimes hard to source. These sprays have the active ingredients of MSMA or DSMA. If you elect to go this way remember your lawn must be healthy to get a good kill. This spray will kill any Blue Couch, Tropika, Buffalo or Broadleafed Carpet Grass in your lawn.

Some grass weeds are only annuals i.e. will grow, put up a seed head, then die. These may be the prevalent grass weed in some lawns that have suffered badly from the drought. To get rid of these weeds keep mowing and fertilizing to get your lawn thick and healthy so they cannot germinate next year.

Another way of getting out grass weeds is with a weed wand, or using rubber gloves and a rag damp with Round-Up (glyphosate) and rubbing this over undesirable grasses. Mix at 3 parts water to 1 part glyphosate. Remember: this mixture will kill any plant so care should be taken; however, if you do kill some of your lawn around the weed, it is typically only 4 to 6 weeks before the lawn will cover that dead area.

The last way to get out weeds (and the cheapest, most efficient, and most environmentally friendly way) is to pull them out. Get the whole family involved! Ideally, wait for some wet weather and then get stuck in when the ground is soft.

Dealing with Nut Grass

Probably the worst weed around is nut grass. This can be controlled by repeated applications with the weed wand/rubber glove and rag treatment. There is now a product on the market called Sempra which will kill nut grass but it is extremely hard to get and not available at all in small quantities. We have begun stocking alternatives at Tanby Garden Centre so if nut grass is driving you mad, give us a call for solutions.

Grubs and Diseases

Our main grub in CQ is the Lawn Army Worm, and these only affect lawns during warmer months. The main symptoms are dying lawns, and the precense of a red wasp hovering over the lawn. Wasps and birds, such as plovers and ibises, are predators that feed on Army Worms.

Identifying Army Worms

To identify army worms, put a wet bag on the lawn in the evening and turn it over in the morning. Any khaki coloured, caterpillar-like grub is an army worm. Alternatively, you can flood a small patch of your lawn and they will come to the surface. Once Army Worms appear, they can be almost impossible to completely remove so it’s your decision whether or not they are doing enough damage to bother with.

If you have laid down new turf, you should certainly spray as the army worm loves the new root shoots of new turf and can do great damage. Insecticides from your local garden centre are the only way to control army worm at this stage. It is very important to spray in the evening, and it helps if the insecticide is washed in with a light sprinkler.

Turf Diseases in CQ

The only turf disease I have observed around the Capricorn Coast is ‘Spring Dead Spot’. This disease appears in autumn as small spots (approx. the size of a 50 cent piece) in your lawn. By early summer spots may join together like lattice work. By mid to late summer, it generally goes away. There are chemical controls of ‘Spring Dead Spot’ but they are not very effective. Usually, good healthy lawn fed with organic fertilizer recovers quite quickly.

Fungal diseases are rarely noticed and their severity in a home lawn situation does not usually warrant treatment. Prevention is the better course and includes the use of organic or slow release fertilisers to encourage steady growth, and not watering during the evening or at night to prevent the build-up and maintaining of humidity and moisture at the plant base. Long thick lawns can also have a problem with high humidity and moisture at the plant base.

If you have a lawn problem and you’d like to speak with the experts, contact the team at Tanby Garden Centre by visiting us at 178 Kinka Beach Road or calling 4939 7200.