Push-pull technology
Encyclopedia
The push–pull technology is a strategy for controlling agricultural pests by using repellent "push" plants and trap "pull" plants. For example, cereal crops
like maize
or sorghum
are often infested by stem borers
. Grasses planted around the perimeter of the crop attract and trap the pests, whereas other plants, like Desmodium
, planted between the rows of maize repel the pests and control the parasitic plant Striga
. Push–pull technology was developed at the International Centre of Insect Physiology and Ecology (ICIPE) in Kenya and Rothamsted Research
, UK by a scientific team led by Dr. Zeyaur Khan.
are both major problems for cereal crops in eastern and southern Africa. Losses to stemborers can reach 80% in some areas and average about 15-40% in others, while those due to striga range between 30-100% in most of the region. When the two occur together, farmers often lose their entire crop. Spraying with pesticides is not only expensive and harmful to the environment, but usually ineffective as the chemicals cannot reach deep inside the plant stems where stem borer larvae reside. Preventing crop losses from stemborers and striga could increase maize and sorghum harvests enough to feed an additional 27 million people in the region.
vulgare sudanense). Napier grass has a particularly effective way of defending itself against the pests: once attacked by a borer larva, it secrets a sticky substance which physically traps the pest and limits its damage.
scheme is provided by plants emitting chemicals (kairomone
s) which repel stemborer moths and drive them away from the main crop (maize or sorghum). The best candidates discovered so far with the repellent properties are members of leguminous genus Desmodium
. Desmodium is planted in between rows of maize or sorghum. Being low-growing, it does not interfere with the crops' growth and furthermore has the advantage of maintaining soil stability and improving soil fertility through nitrogen fixation
. It also serves as a highly nutritious animal feed and effectively suppresses striga. Another plant showing good repellent properties is molasses grass (Melinis
minutiflora), a nutritious animal feed with tick
-repelling and stemborer larval parasitoid attractive properties. The leguminous family crops such as ground nuts can produce certain chemicals like Etheline in small quantities, this is one of the chemicals produced by maize and it stimulates the growth of striga (witch weed), when you inter crop such legumes with the cereals the chemicals they produce will stimulate the growth of stiga and since the legumes will not allow the attachment of haustoria (roots of the striga) to their roots, they will die due to lack of nutrients. This practice therefore reduces the seed bank of the striga weeds in the soil.
Cereal
Cereals are grasses cultivated for the edible components of their grain , composed of the endosperm, germ, and bran...
like maize
Maize
Maize known in many English-speaking countries as corn or mielie/mealie, is a grain domesticated by indigenous peoples in Mesoamerica in prehistoric times. The leafy stalk produces ears which contain seeds called kernels. Though technically a grain, maize kernels are used in cooking as a vegetable...
or sorghum
Sorghum
Sorghum is a genus of numerous species of grasses, one of which is raised for grain and many of which are used as fodder plants either cultivated or as part of pasture. The plants are cultivated in warmer climates worldwide. Species are native to tropical and subtropical regions of all continents...
are often infested by stem borers
Ostrinia
Ostrinia is a genus of moths in the Crambidae family. Several of them, including the European Corn Borer, are agricultural pests.-Species:*Ostrinia avarialis Amsel, 1970*Ostrinia dorsivittata...
. Grasses planted around the perimeter of the crop attract and trap the pests, whereas other plants, like Desmodium
Desmodium
Desmodium is a genus in the flowering plant family Fabaceae, sometimes called tick-trefoil, tick clover or beggar lice. There are dozens of species and the delimitation of the genus has shifted much over time....
, planted between the rows of maize repel the pests and control the parasitic plant Striga
Striga (plant)
Striga, commonly known as witches weed, is a genus of 28 species of parasitic plants that occur naturally in parts of Africa, Asia, and Australia. Witchweeds are characterized by bright-green stems and leaves and small, brightly colored flowers. Furthermore, they are obligate parasites of roots...
. Push–pull technology was developed at the International Centre of Insect Physiology and Ecology (ICIPE) in Kenya and Rothamsted Research
Rothamsted Experimental Station
The Rothamsted Experimental Station, one of the oldest agricultural research institutions in the world, is located at Harpenden in Hertfordshire, England. It is now known as Rothamsted Research...
, UK by a scientific team led by Dr. Zeyaur Khan.
Pests of cereal crops
Stemborers and the parasitic plant strigaStriga
Striga may refer to:*Strigoi, a legendary Romanian vampiric creature; also can be seen in some myths as more of a witch.*Striga , a parasitic weed-See also:...
are both major problems for cereal crops in eastern and southern Africa. Losses to stemborers can reach 80% in some areas and average about 15-40% in others, while those due to striga range between 30-100% in most of the region. When the two occur together, farmers often lose their entire crop. Spraying with pesticides is not only expensive and harmful to the environment, but usually ineffective as the chemicals cannot reach deep inside the plant stems where stem borer larvae reside. Preventing crop losses from stemborers and striga could increase maize and sorghum harvests enough to feed an additional 27 million people in the region.
The pull
The approach relies on a combination of companion crops to be planted around and among maize or sorghum. Both domestic and wild grasses can help to protect the crops by attracting and trapping the stemborers. The grasses are planted in the border around the maize and sorghum fields where invading adult moths become attracted to chemicals emitted by the grasses themselves. Instead of landing on the maize or sorghum plants, the insects head for what appears to be a tastier meal. These grasses provide the "pull" in the "push–pull" strategy. They also serve as a haven for the borers' natural enemies. Good trap crops include well-known grasses such as Napier grass (Pennisetum purpureum) and Sudan grass (SorghumSorghum
Sorghum is a genus of numerous species of grasses, one of which is raised for grain and many of which are used as fodder plants either cultivated or as part of pasture. The plants are cultivated in warmer climates worldwide. Species are native to tropical and subtropical regions of all continents...
vulgare sudanense). Napier grass has a particularly effective way of defending itself against the pests: once attacked by a borer larva, it secrets a sticky substance which physically traps the pest and limits its damage.
The push
The "push" in the intercroppingIntercropping
Intercropping is the practice of growing two or more crops in proximity. The most common goal of intercropping is to produce a greater yield on a given piece of land by making use of resources that would otherwise not be utilized by a single crop. Careful planning is required, taking into account...
scheme is provided by plants emitting chemicals (kairomone
Kairomone
A kairomone is a semiochemical, emitted by an organism, which mediates interspecific interactions in a way that benefits an individual of another species which receives it, without benefiting the emitter. This "eavesdropping" is often disadvantageous to the producer...
s) which repel stemborer moths and drive them away from the main crop (maize or sorghum). The best candidates discovered so far with the repellent properties are members of leguminous genus Desmodium
Desmodium
Desmodium is a genus in the flowering plant family Fabaceae, sometimes called tick-trefoil, tick clover or beggar lice. There are dozens of species and the delimitation of the genus has shifted much over time....
. Desmodium is planted in between rows of maize or sorghum. Being low-growing, it does not interfere with the crops' growth and furthermore has the advantage of maintaining soil stability and improving soil fertility through nitrogen fixation
Nitrogen fixation
Nitrogen fixation is the natural process, either biological or abiotic, by which nitrogen in the atmosphere is converted into ammonia . This process is essential for life because fixed nitrogen is required to biosynthesize the basic building blocks of life, e.g., nucleotides for DNA and RNA and...
. It also serves as a highly nutritious animal feed and effectively suppresses striga. Another plant showing good repellent properties is molasses grass (Melinis
Melinis
Melinis is a genus of grass in the Poaceae family.- Selected species :M. affinis MezM. ambigua Hack.M. angolensis RendleM. arenaria Hack.M. argentea MezM. ascendens MezM. bachmannii Mez...
minutiflora), a nutritious animal feed with tick
Tick
Ticks are small arachnids in the order Ixodida, along with mites, constitute the subclass Acarina. Ticks are ectoparasites , living by hematophagy on the blood of mammals, birds, and sometimes reptiles and amphibians...
-repelling and stemborer larval parasitoid attractive properties. The leguminous family crops such as ground nuts can produce certain chemicals like Etheline in small quantities, this is one of the chemicals produced by maize and it stimulates the growth of striga (witch weed), when you inter crop such legumes with the cereals the chemicals they produce will stimulate the growth of stiga and since the legumes will not allow the attachment of haustoria (roots of the striga) to their roots, they will die due to lack of nutrients. This practice therefore reduces the seed bank of the striga weeds in the soil.
See also
- Cultural methodsCultural methodsIn agriculture, cultural methods are practices used to enhance crop and livestock health and prevent weed, pest or disease problems without the use of chemical substances...
- Sustainable agricultureSustainable agricultureSustainable agriculture is the practice of farming using principles of ecology, the study of relationships between organisms and their environment...
- List of sustainable agriculture topics
- EcotechnologyEcotechnologyEcotechnology is an applied science that seeks to fulfill human needs while causing minimal ecological disrupution, by harnessing and subtly manipulating natural forces to leverage their beneficial effects...
- List of companion plants
- List of beneficial weeds
- List of repellent plants