African black beetle in cereals

Control options for African black beetle in winter cereals are very limited, but fortunately feeding activity will decrease soon.

An African black beetle adult (Source: Trevor James, AgResearch, NZ)

 

African black beetle (Heteronychus destructor, ABB) is one of those extraordinarily pesky pests in that it has a taste for a multitude of plant species, impacting broadacre, horticulture, pasture and forestry production systems.

While not considered a major pest of winter grains, some cereals are susceptible to damage by ABB adults. This includes wheat and triticale, as has been observed recently in the NSW Southern Tablelands. Barley is also thought to be susceptible to damage by ABB.

African black beetle has a one-year life cycle. Eggs are laid by adults in spring and larvae develop between November and March. Adult beetles emerge during autumn and threaten establishing crops during autumn-winter.

Available control strategies for ABB are largely focused on pasture-based systems (e.g. use of endophyte varieties) and horticulture and turf management, which are generally not applicable to management in cereal crops.

There are no insecticides registered in winter cereals for control of ABB.

The good news is that feeding by ABB adults will decline with the onset of winter.

If ABB damage in cereals is an ongoing issue in your region, there are some cultural controls which can assist in future management:

- Increasing seeding rates is a useful option in paddocks where the pest is anticipated to cause damage.  

- Removing alternative food sources in and around the paddock. This includes winter grass (Poa annua), paspalum, annual ryegrass, phalaris, and kikuyu.

- Rotating ABB-affected paddocks with an unfavourable crop or pasture. Planting a legume, chicory or brassica species in spring is likely to disrupt ABB at the larval stage of development.

Predicting the likelihood of damage from ABB is not always possible. The absence of developing larvae in a paddock throughout the previous spring/summer does not necessarily mean that paddock will be free from the threat of adults come autumn and winter.

Adult beetles have strong nocturnal flight activity and disperse during their ‘roaming’ stage primarily in autumn, leading to paddocks becoming infested.

Are you seeking further information on this pest? Visit our comprehensive African black beetle PestNote.

 

Field reports of African black beetle

Ben Lenehan – Delta Agribusiness (Southern Tablelands, NSW).