African Lawn Beetles, also know as Black Lawn Beetles are often held responsible for creating a massive amount of damage to lawns. Also, many times when lawns begin suffering damage or stress - the lawn beetle is again held responsible, regardless of whether a single beetle has been seen or not.
It is true that Black Lawn Beetle can cause severe damage in a lawn, but in real truth this is an extremely rare occurrence, and in practice when lawn owners do blame Black Beetle for lawn damage - it is in fact not the cause in well over 99% of cases.
As Black Beetles feed, they will continue to move throughout the soil, never staying in a single place too long, meaning no damage can ever really occur to the lawn - because the beetles and grubs will never eat and destroy more than a tiny fraction of the root system of the lawn in any one place.
This is part of natures control mechanisms for the Beetle, for if they ever did destroy a lawn - then their food supply would also be destroyed - and so would their species as a result. So they really are programmed to eat a little - move on - and let the lawn recover to later provide more food.
In almost every case - the Black Lawn Beetle is truly a good friend to the lawn owner. Their constant burrowing provides valuable and free aeration of the soil. Their mild eating away at the roots of the lawn also encourages new root growth which is far more efficient and beneficial for lawns to take nutrients from the soil with.
Black Lawn Beetles are also only ever active at exactly the same time as the lawn is most active in it's growing cycle, so any very minor effects that the Black Beetle may cause is very quickly repaired or never even seen in a healthy lawn. When the lawn goes dormant over Winter, so do the beetles and their grubs.
Black Lawn Beetles and their grub offspring feed regularly on the roots of lawns, and if ever found in concentrated very large quantities then this feeding can cause damage to the lawn and only then should treatment be considered.
In theses cases - a inexpensive powder insecticide is applied to the soil and watered in, this will very effectively kill most lawn beetles in the soil, in a single application.