Push–pull agricultural pest management

Push-pull technology is a method for biological pest control. Here, within the crop with repulsive to the culture of those with attractive effect used by the insects from the crops distribute (push) or to attract (pull ).

Development

The infestation by stem borer, a relative of the European corn borer, leading to significant crop losses for small farmers in East Africa. Other problems include the parasitic Strigakraut and the low nutrient content of tropical soils. Pesticides and fertilizers are unaffordable for subsistence farmers. To combat drill stem Men was developed in collaboration with the Kenyan Acriculture Research Institute ( KARI ) and Rothamsted Experimental Station, the push-pull technology at the International Centre of Insect Physiology and Ecology ( ICIPE ) under the conductor Hans Rudolf. It was discovered that Desmodium ( Desmodium adscendens ) not only repels the moths of the stem borer, but also kill the Striga.

Operation

Desmodium as a repellent is planted between the rows of corn, while Napier grass ( Pennisetum purpureum ), also called elephant grass, as a "trap" is planted in a belt around the field. Thus, the stem borer moths are lured away from cereals towards the Napier grass to lay their eggs on the leaves instead of corn. Repulsive and attractive effect based on so-called leaf volatiles, which can be compared with odors and insects serve for orientation and to locate the host plant. Napier grass and Desmodium are perennial and can easily persist over ten years. Is the grain harvested, the grain rows are chopped or plowed, while the rows of Desmodium and Napier grass are only trimmed back before re- sowing.

Combat drill stem

While the Desmodium Volatile ejects the stem borer repel the Napier grass produces a Volatile mix that is similar to the grain. However, in much larger quantities than is the case with the grain so that the stem borer females deposits its eggs preferably on the leaves of Napiergrases. If the resulting hatching larvae attempt to penetrate into the stem of the grass, this produces a slimy substance that kills the pest.

Combating Striga

The parasitic Striga germinates when the seed is the presence of so-called root exudates perceives that are submitted by the maize roots. As a result, it attaches itself to these and cut corn plant sugar. Desmodium produces the root exudates, which also stimulate the germination of the Strigasamens simultaneously but also substances which kill the germs once. So the seeds are prevented not only on the development but actively removed from the soil. This is important because a single Striga plant produces up to 20,000 seeds, which remain viable for up to 20 years in the soil.

Improvement of soil fertility

Like all legumes Desmodium can bind atmospheric nitrogen organic and so make it available to its growth and that of the surrounding plants. In the research at ICIPE was found that the released amount of nitrogen corresponds almost exactly, needs corn for optimal growth. In addition, the ground supplied by decaying leaves and roots of Desmodiums organic material, the soil organisms promotes and increases nutrient availability.

Supply of cattle feed

Napier grass is very fast growing and is up to four meters high. Parts of the Napier grass belt can be harvested without affecting the protective function and are used as cattle feed. Desmodium also, when it is cut back after harvest, are used as feed. The mixture of the two plants is rich in nutrients and is in the dry season are available when other food sources dry up.

Other positive effects

Through the land cover of Desmodium, the soil is protected from erosion. In addition, the evaporation is inhibited by the increased shading and water retention improves. The seeds of Desmodium can be harvested and sold. The proceeds of 600 KSh ( around 6.50 Eur per kilogram) is a welcome source of cash.