The world's population is exponentially increasing which implies food production is also growing. In order to satisfy the growing demand, producers make massive use of pesticides, herbicides, and fertilizers to produce more and prevent pests from obliterating crops. However, this has a cost, as these compounds' high toxicity causes the death of millions of species.
The most aggressive pesticides have been banned for years in the European Union, but they are still found in the river basins of many rivers. In addition to affecting animal and plant species, according to the UN, the inappropriate use of these substances causes the death of 200,000 people a year, especially in developing countries.
But are pesticides really necessary to feed the world? A scientific article published this month in the Communications Biology journal reveals that it does not and proposes using natural enemies as an alternative to pesticides. According to experts, biological control of pests relieves the pressure on the land and contributes to the conservation of the natural environment.
The authors of the article are a group of researchers from the University of Agriculture and Forestry of Fujian (China) and the Center for International Cooperation in Agronomic Research for Development (CIRAD), which includes entomologists (experts in insects), biologists specialized in ecosystem conservation, agro-ecologists, and geographers.
The experts' goal is to eradicate the widespread belief that biological control of pests represents a danger for crops and for humanity because it is less effective. To do this, researchers focused on one of the biggest enemies of cassava (Manihot esculenta), a shrub extensively cultivated in America, Africa, and Oceania for its roots that have starches of high nutritional value.
The results of the work are aimed mainly at producers in Thailand, Vietnam, Cambodia, and Laos, which account for almost the of the world's cassava export market, and offers them an effective solution to stop the proliferation of the cassava cochineal (Phenacoccus manihoti), an insect that began to devastate extensive areas of cassava crops in Thailand in 2008.
At first, farmers reacted to the pest by spraying their fields with toxic insecticides that posed a high risk to people and the environment. Their response was justified because they lost 20% of the expected profits for that year.
Thai authorities asked the International Institute of Tropical Agriculture in Benin for help, as decades ago it had helped several African countries to control this plague.
They had succeeded to control de plague by using the Anagyrus lopezi, a species of parasitic wasp that deposits its eggs in the cassava cochinchilla. The larvae contained therein feed on the host, thereby killing it quickly.
Given the success in Africa, the same technique was implemented in Thailand in 2010 and, thanks to it, a large part of the hectares infested in 2008 were recovered and deforestation was also significantly reduced. A series of satellite images recently published show that there has been a 30 to more than 90% reduction of deforestation in some areas.
Cassava is a very versatile product, as it can be used to make industrial products, such as adhesives or paper, as well as by the pharmaceutical industry and, of course, by the food industry.