Ecogrow

African Black Beetle heteronychus arator

Life Cycle

The scarab beetle grubs rather than the adult beetle cause most turf injury. The grubs feed on the roots of the grass, leading to, reduced ability of the grass to take up nutrients and water from the soil.


Identify | Damage to: Turf - Field Crops - Glasshouses | How to Control | Application | Hint
Turf:


The scarab beetle grubs rather than the adult beetle cause most turf injury. The grubs feed on the roots rhizomes of the grass, leading to, reduced ability of the grass to take up nutrients and water from the soil. Therefore grass wilts and dies quickly in times of slight water or heat stress. If the problem is not addressed quickly, the larvae will destroy the turf. Large irregular patches, regardless of heat and water conditions is usually the first sign of damage.

Scarab beetle damage can initially be diagnosed as drought stress. Heavily infested areas appear wilted, which, with continued feeding will cause turf loss.

These features will not always be seen in turf with a black beetle problem. Another indicator is damage to the turf from birds searching for the grubs as food. Birds can cause a great deal of damage. They tear at the turf and roll it back like a carpet to get at the grubs.

Once the roots are seperated from the soil. Costs for the remedial work become significantly higher.

Although the African Black Bettle has only one generation per year, it is common to find life cycle stages out of phase with the main population. Therefore it is possible to find eggs, young larvae, older larvae, new and old generation adults at one time of year.

Field grown crops:

The insect's grubs are very damaging root feeders. This causes the plant to weaken and may die in times of slight heat or water stress. This can be identified easily as effected plants loose their stability and wilt. Unless the pest is treated they will continue to feed on the roots and the plant will die regardless of water content in the soil. This is easily seen throughout the growing areas. Individual plants, which are located in areas where other plants appear to be growing well, will die. With increased populations of the insect, and the insect's grubs, increased numbers of dying plants will be obvious.

Scarab beetle grubs are also known to burrow into tubors eg: potatoes and kumara, resulting in decreased crop yield.

Scarab beetles and their grubs are considered a relatively minor pest of glasshouses. Should you see this happening in your glasshouse careful searches should be made to locate and identify the pest. It is more likely that it may be Black Vine Weevil, which causes almost identical injury and is a much more common pest of glasshouses throughout Australia.

Glasshouses:

The insect's grubs are very damaging root feeders. This causes the plant to weaken and may die in times of slight heat or water stress. This can be identified easily as effected plants loose their stability and wilt. Unless the pest is treated they will continue to feed on the roots and the plant will die regardless of water content in the soil. This is easily seen throughout the growing areas. Individual plants, which are located in areas where other plants appear to be growing well, will die. With increased populations of the insect, and the insect's grubs, increased numbers of dying plants will be obvious.

Scarab beetle grubs are also known to burrow into tubors eg: potatoes and kumara, resulting in decreased crop yield.

Scarab beetles and their grubs are considered a relatively minor pest of glasshouses. Should you see this happening in your glasshouse careful searches should be made to locate and identify the pest. It is more likely that it may be Black Vine Weevil, which causes almost identical injury and is a much more common pest of glasshouses throughout Australia.

Control:

Using EN's

It is of the utmost importance to wash the nematodes from the turf into the soil surface after application. Apply at dusk when damaging sunlight is at a minimum. Soil temperature must be within the range of 15-30 o C. Area to be be treated should be thoroughly moistened before applying to enable the nematodes to travel on a film of moisture in the soil. Immediately after applying, water the turf again to wash the nematodes from the grass onto the soil surface.

Apply nematodes uniformly to ensure that each square metre receives the same amount of nematodes. A two-way drenching pattern, applying half of the total solution in each direction can also be done.

Method:

Click here to see application Instructions. The following refers to Home Lawns only.

Use 1 tub for 200-250 square metres depending on the severity of infestation. Add 1 tub to at least 40 litres of water at (10-25 C), at least 10 minutes before use and stir well to suspend nematodes. Conversely use 1/5 of a tub each time to 9 litres of water i.e. 1 bucket.

A watering can (9 litres) with a fine rose (nozzle) can be used to apply the solution. Agitate or stir the suspension each time before pouring more solution into the watering can.

Apply in sections. A length of garden hose may be useful for visually marking of each section. It is also advisable to familiarise your self with how much area will be covered by your watering can by using plain water before applying nematode solution. The recommendation of 1 tub per 40 litres of water in a minimum requirement and as a rule of thumb the more water applied with the nematodes the more even the coverage will be. Ensure your application is watered in well but avoid flooding or application evenness may be affected.

20 litres water per 100 metres squared so 40 litres water per 200 metres squared.

Hint
Underfoot the turf feels spongy and soft and can be rolled back like a loose carpet due to the destruction of the roots, causing the turf to loose it's grip on the soil.

Watch birds carefully if they are paying particular attention to the turf in a specific area, it is likely there are abundant pests in the soil. Treat the area immediately otherwise turf loss will inevitably occur.


Larva
Damage
Damage