Lawn Grubs / African Black Beetle – What, Why, & How !

Life Cycle: Black beetle eggs are laid in spring and early summer, hatching into larvae that feed on grass roots. As they mature through three stages, they grow to about 25mm in length. When the weather warms up, usually from September to March, and after heavy rain, the larvae become most active. They then progress into pre-pupae and pupae stages, causing no harm to the lawn, before emerging as adults in late summer or early autumn. The adult beetles are black, shiny, about 15mm long, with brown serrated legs, and are dormant or semi-dormant through the winter, restarting the cycle by laying eggs in spring.

Symptoms: Extensive root damage by larvae can lead to inefficient moisture and nutrient uptake, causing the grass to become dry and straw-like, similar to during severe drought conditions. Severely affected grass can be easily peeled back from the soil surface, revealing a large number of feeding larvae.

Treatment: Due to the rapid feeding and movement of the grubs, the large number of eggs they lay, and the sheer volume of an infestation, prompt treatment is crucial. Consult with your local turf farmer for advice and treatment options. Fast-acting insecticide products, such as Lawn Solutions Battle Insecticide, can be effective. Ensure to follow the manufacturer’s handling and safety instructions. Apply the treatment late in the day when the adults are active, and reapply after two weeks to eliminate any missed eggs or grubs.

Prevention: Grub attacks can occur multiple times during a season, affecting any lawn. Preventative measures like Grub Guard Ultimate, Acelepryn GR, and Acelepryn Liquid can be effective. Acelepryn targets pests such as black beetles, stem weevils, cutworms, and armyworms, providing safe and effective control while minimizing the impact on the environment and non-target organisms like bees and earthworms. Applying these products in spring can protect your lawn for up to six months. Visit our shop to buy these products