PEST
 
   NAME
     African Black Beetle
     Heteronychus arator
 
   ORDER
     Coleoptera
 
   FAMILY
     Scarabaeidae

Description of the Pest
The African Black Beetle is a stout scarab, with glossy black wing covers and up to 12mm long.  The cream coloured larva or curl grub is up to 25mm long. It has a fleshy body with a hard shiny head capsule. The larva has a characteristic ‘C’ shape. It has true legs and the end of the abdomen is slightly swollen with a darker internal colour. Its mandibles are large jaws. Both adult and larva have chewing mouth parts.

Adult		 Adult note the front legs

Life Cycle
This insect has a Holometabolous life cycle, i.e. it has a larval and a pupal stage.
The adult lays eggs in the soil over a three month period and both eggs and larva can be found in the soil at the same time. There are several larval stages before pupating in the soil during mid summer and emerging as adults. The adults live for up to a year but overwinter in the soil in a semi dormant state.

Distribution of the Pest
This insect pest is widely distributed throughout Australia and New Zealand. Native to Africa
Larva in the soil		Typical C shaped larva

Period of Activity
The adult is active during spring followed by the larvae. . The adults are seen flying in late spring and late summer to autumn seeking soft moist soil to for egg laying.

Damage Caused
The adult beetle and lava feed on below ground parts of the plant, but it is the lava that causes most of the damage with there prominent jaws. Small roots are completely eaten and larger root have sections eaten away. This causes seedlings to topple and die or small shrubs loose vigour. Lawns develop dead patches particularly during dryer weather as the lava eats the roots. The late larval stages cause the most damage as it becomes larger and active. The lava is not normally seen but loss of colour in foliage plants or dead patches in lawns may indicate its presence. Plants attacked can be easily removed for the roots have been eaten. This pest is normally associated with bent & couch grass although they can feed on the roots of shrubs and trees. Damage by the feeding adults is normally minor.
 
Chewing Mouth parts	Note dark area on larva

Susceptible Plants
There are many plants that are attacked by this pest including dahlias and petunias. Vegetables such as tomato, beetroot cabbages and cauliflowers are also attacked. Potted plants in gardens or in a nursery situation may become infested, drastically reducing the vigour of the plant.

Turf Grasses are susceptible to infestation causing greens to become bumpy and a secondary damage is caused by birds fossicking for grubs and the adult beetles emerging at night to feed. 
There are several types of Scarab Grubs including the Blackheaded Pasture Cockchafer (Aphodius tasmaniae), which feeds on the leaves that it collects and stores in vertical soil tunnels for up to a week. It then returns at night after rain to collect more leaves. 

Other species include the Argentinian Scarab (Cyclocephala signaticollis), Brown Cockchafer (Ataenius imparalis), Prinrose or Lawn Scarab (Sericesthis germinate) and the Readheaded Cockchafter (Adoryphorus couloni). All of these species cause sporadic damage to Turf Grass.

Control

Cultural Control
It is difficult to rid lawn areas of this pest using cultural methods. Garden lighting attracts the adult beetles. 

Biological Control
Nematodes (Heterorhabditis zealandica) Birds with large beaks such as magpies feed actively on exposed larva but they can cause damage by their feeding to turf areas.
 Areas may be forked to reveal the lava, particularly during spring when they are close to the surface.

Chemical Control
Insecticides may not be economic unless the larvae are in a confined area such as a pot 
Various insecticides are available. There has been some success with the use of small amounts of eucalyptus oil diluted in water and applied to the infected area when the adults are seen in Spring as the larvae are close to the surface.

Note
It is your responsibility by law to read and follow the directions of any pesticide

Monitoring
Pit fall and light traps for the adults.
Soil cores for the larva
Amendments by B. Sonsie Dip Hort Sc Burnley