Pests and lawn care
In the turf industry, a pest is a generic term given to weeds, insects and diseases, alike. For now, I’m going to make it simpler by terming pests as insect invaders.
Most lawn pests lay their eggs in the spring. Hereby, they give their young most of the spring, all of the summer and into autumn, the chance to thrive on a host (your lawn). Your lawn is full of highly nutritious food to make them grow strong and lay their eggs in the next season so that the next generation can be spawned. The problem is that your lawn is the pests feeding ground. Moreover, in great numbers, they will decimate a lawn in a few days.
Identify pests in your lawn
A simple test to initially identify a potential problem is to get a watering can full of water and mix in some washing detergent. Make sure it is mixed in; and don’t put the washing detergent in first. YOU DO NOT WANT IT TO FROTH! Pour the soapy water over several sections of your lawn area with each area covering about one square metre. Make sure that each area gets a good drenching- about a litre per square metre. The mix will seep into the soil and acts as an irritant to just about every bug in the upper soil profile. Any bug in that area will quickly surface and can then be identified. If you have 10+ bugs of any description in that square metre area, you may have a problem that needs to be addressed immediately.
If you do find pests it is imperative that you take action as soon as possible. Remember, pests see your lawn as a breeding ground.
The attached PDF shows a chart of the most common pests (insects), the stage in life they are most aggressive towards a lawn, what signs to look for and what treatment can be used.
Most common pests
There are three common types of Armyworm found in southern Australia- common, southern and inland. The moth (above) lays its eggs in batches which hatch within three weeks depending on climatic conditions.
The young larvae don’t do much damage but, as they grow, they can become voracious feeders and, in numbers, will become destructive to lawns. After several more weeks, they bury themselves underground where they pupate. After four to six weeks, they metamorphose into moths and fly away.
When in a feeding frenzy, they will gather in numbers and chew the leaf blade above the crown. In full sun, the lawn will almost always recover. In full shade, due to the restriction of the proper process of photosynthesis, the lawn will most likely die off in patches or altogether.
African Black Beetle
The African Black Beetle lays its eggs in early to mid spring. The eggs hatch within six weeks and the larvae will burrow down to 100 to 150mm. The young larvae feed on the organic matter within the soil but as they grow older their taste develops for plant roots. The plants require nutrients and water to be taken up through the roots. When this is disrupted, the plant will discolour.
In late summer, the larvae will, again, burrow down to 100mm to pupate. Metamorphosis takes about a month and the adult beetle will emerge in late summer to early autumn. They will feed over winter, mate in early spring and lay their eggs about 10mm under the surface of the soil. In early summer, the adult beetle will die.
Ground Pearl (Pink Pearl)
During late spring or early summer, adult female (there are no males) ground pearls emerge from their white, pearl cysts These adults are pink, in colour, and derive their name from this. Once they’ve emerged, they migrate and then lay up to 100 eggs into a chamber consisting of a wax-like filament (which is white, in colour). Under favourable conditions, a female may have several egg-layings a year. The eggs hatch after several days and the first hatchlings (crawlers) leave their chamber and seek out a healthy root on which to feed. Once established, the nymphs begin to secrete an outer, waxy-like covering and over summer and early autumn, the nymphs continue to develop into the adult stage. By late autumn and early winter, the nymphs metamorphosis into adults which have turned pink in colour by this stage. They hibernate over winter in the cysts (pearl) surrounding them and emerge in late spring and early summer.
The name, Cutworm, is derived from the larval stage where most of the damage to the plant is done. In particular, cutting through the stem at, or just above, ground level. The Cutworm is a generic name given to the larval stage of several different species of moths.
Eggs are laid in early autumn and under favourable conditions, they can go through the larval and pupae stage before emerging as adults within 10 weeks. Young larvae will climb plants and skeletonise leaves or make small holes. As they get older, they spend more time nearer the ground, cutting through stems and feeding on the growth of felled plants. They usually feed during the coolness of late afternoon and early evening, hiding in vegetation during the day from the heat and predators.
These fellows are native to North America and, as yet, are not in Australia. The reason for its’ entry is that we have many north Americans landing on this page and so it’s worth a mention. They excel under very hot, dry conditions
The Chinch Bug is a reddy-orange colour in the juvenile stage, turning to a darker red to brown with an attractive black and white pattern on their back as they mature to the adult form. Adults are about 4-5mm in length and cluster to form a mass on healthy, vegetative tissue. They have a life-cycle which runs for about a year but they spawn two generations during that year which develop at two different times- one is hatched in spring and dies in the autumn; the other hatches is summer and hibernates over the winter before laying eggs and dying in the spring.