SCARUB GRUBS IN CANBERRA

Scarab Grubs have been an ongoing problem for some time in the Southern Tablelands and Southernn Highlands areas of NSW and are a major cause of concern for customers. And rightly so, as the effects of a Scarab Grub attacks can be demoralising for the keen gardener. Scarab Grubs
feed on the roots of grasses and can lead to patches or whole lawns dying. Birds can also do damage because they plough up large clumps of lawn in the process of feeding on the Scarab Grubs. Autumn is the time when lawns are normally affected after a high infestation of Scarab Grubs. At this point it is too late to prevent damage, as the Scarab Grubs would have finished eating and are
now developing into their beetle form. This unfortunately is the time when we at Canturf receive a lot of calls and there in not a lot we can do at this stage. To use an old adage, “Prevention is far better than cure”. This is achieved by maintaining a deeprooted
properly fertilised lawn, which preferably contains O’connor’s Strawberry Clover. Clover being a legume and not a grass seems to be less susceptible to damage.

No grass is resistant to Scarab Grub attack and as much as we would love to promise otherwise this would be untrue. Canturf uses seed with high endophyte levels and while this can repel some lawn grubs such as Argentine Stem Weevil there is no evidence suggesting this repels Scarab Grubs. On the other hand there are legumes like O’connor’s Strawberry Clover and other clovers which are rarely affected by Scarab Grubs because the female beetles like to lay their eggs in the roots of grasses and find legume roots unattractive. Canturf and the ACT Parks and Conservation Service have found that Scarab Grub attacks are a lot less severe in lawns with some clover in them.
Clover helps to provide a cover until the grass repairs. The beauty of O’Connor’s is that, being a small leafed clover, it looks good, it is nice and soft, it’s hardy, it does not attracted bees as much as larger flowering clovers and being a legume, it adds nitrogen back into the soil. Chemical control of Scarab Grub attack is difficult but may be worthwhile if the attack is particularly
serious and the problem is detected at an early stage in the life cycle of the Scarab Grub. We don’t recommend the wider spread use of chemical control for a number of reasons:

1. Chemicals kill useful as well as harmful bugs and organisms. Birds may also die after they feed on the treated grub.

2. It is difficult to pick the exact time for chemical application because the Scarab Grub in the larvae stage is only susceptible to insecticides for a short period of its life cycle. Even then the chemical must reach the level in the soil where the Scarab Grub is feeding. This is achieved by watering in the chemical and it is difficult to be accurate.

3. There are a number of species of Scarab Grub, which may cause damage, and there needs to be correct identification as the timing of chemical application varies between species.

IMPORTANT POINTS
Scarab Grubs do more damage to wet, weak lawns. A healthy strong growing lawn will resist and survive attack more easily. Deep watering combined with a good fertiliser program, such as that recommended on the back of a Canturf “Grow Green” fertiliser packet, is essential to achieve a healthy lawn. “Less more often” is the trick with fertilising.
A constant level of nutrients will allow a lawn to be healthy all year round. Humans prefer three meals a day opposed to one huge meal, similarly with lawns regular small applications rather than infrequent large doses are preferable. A lawn becomes stressed if too much fertiliser is used at once. Canturf does not recommend the use of chemicals for Scarab Grub control but rather the use of good management practices. If it is seems necessary to spray then a very scientific approach should be taken with correct identification of Scarab Grub species, timing, and procedure. For more information please do not hesitate to contact us at Canturf. Should you require any further information please give us a call on 1300canturf or email us at canturf@canturf.com.au