SA Grain October 2017

Produk-inligting

Oktober 2017

Wheat:

Value of intercropping

when managing insect pests

any producers want sustainable crop production sys-

tems that will reduce input costs of chemical fertilisers

and pesticides, and make the whole system more resil-

ient during times of environmental fluctuations such as

periods of drought.

Intercropping your grain crops might help you to achieve this goal.

Intercropping is the cultivation of two or more plant species in the

same field at the same time. This includes the use of insectary plants,

border crops, cover crops, and water reservoirs. These can be estab-

lished perennial plants into which an annual row crop can be seeded.

Intercropping is an ecological approach or tool that can be com-

bined with other strategies. There are many different approaches

and strategies. A good idea is to start with a simple intercropping

plan, such as including strips of a cover crop within the cash crop,

based on the producer’s observation that a flowering cover crop at-

tracts beneficial insects.

The producer may later add other elements such as perennial border

crops of herbs and flowers that repel pest insects and provide ben-

eficial habitats to support natural enemies of the farm’s major pest

insects. In this way, the agricultural cropping system can gradually

be turned into a more diverse system.

The choice of plants for intercropping will depend on the specific

system, the geographical area and the insects occurring in these

areas. A good plant to choose would be a hardy perennial that is

drought tolerant, will attract beneficial insects and repel pest

insects, have a deep root system that can accumulate potassium,

phosphorus, and copper from the subsoil and can be used as a liv-

ing mulch and cover crop in dry areas. The plant should be adapted

and grow well in the specific area.

Ideal intercrop plants will provide food and shelter for all life stages

of beneficial organisms, suppress weeds, and grow in close proxim-

ity to the cash crop without competing for space, light, water and

nutrients. The cover crop and cereal should occupy different above

and below-ground niches and should complement each other, in-

creasing the cropping system’s ability to capture and use resources,

such as sunlight, water and soil nutrients, efficiently.

Legumes, clovers and many herb species such as yarrow, fennel,

tansy, catnip and African wormwood fit these criteria. In planning

Besproeiing

1: A ladybird pupae on tansy.

2: A ladybird larvae on tansy.

3: A ladybird adult.

4: Wheat monoculture.

5: Russian wheat aphid – a wheat pest.

Winter grain region

FOCUS

Special

DR ASTRID JANKIELSOHN,

ARC-Small Grain, Bethlehem