April 03, 2012
African Black Beetle - Heteronychus Arator
These shiny black beetles are about 12 mm long. They chew stems just below ground leve, leaving a frayed edge. Plants may wilt and fall over. Holes may be chewed in potatoes, and the eyes of seed potatoes may be damaged. Strawberries my be hollowed out from beneath.
Adults become active in spring, and mating occurs. Eggs are liad in areas of soft soil, larvae and adults can both be found in the soil at any one time.
Young larvae feed on dead organic matter in the soil, but older larvae feed on grass roots. Most damage to lawns and other turf is caused by the last larval stage. Heaviliy damaged grass appears to need watering and can easily be pulled up. Brown patches may appear. The larvae are typical hite curl grubs and grow to about 25mm. They pupate in the soil and emerge as adults from mid-January to late February/early March. These adults feed until the weather gets cold, then burrow into the soil and become semi-dormant. Pest numbers are high after prolonged dry weather.
PLANTS ATTACKED - A wide range, including lawn grasses, sweet corn, potatoes, tomatoes, beetroot, bananas, grapevines, cabbages, cauliflowers, dahlias and petunias. They do not feed on legumes.
CONTROL - Treat for black beetle in the spring because the very young larvae are near the soil surface and are easier to kill.
Organic/Non-chemical: Fork over garden beds and expose any larvae to birds. Avoid garden lights. They attract beetles.
Chemical: Apply fenamiphos granules to lawn areas as directed on the label. Water the lawn thoroughly after application. There is no home-garden chemical suitable for control in other plants. However, if black beetle is controlled in the lawn, damage to other garden plants should be minimal.