Garlic, oranges, chillies and sex pheromones are among the potentially viable natural control measures that could be used against fall armyworm, according to a study
Researchers have identified a number of pesticides derived from natural materials such as animals, plants, bacteria, and certain minerals – also known as biopesticides – that are safe, sustainable and effective against the fall armyworm in Africa.
Fall armyworm is devastating crops across the continent. Last year, Ghanaian farmers experienced an estimated 45 per cent loss and in Zambia there was 40 per cent loss from the destructive pest.
The annual total production loss was 8.5 to 21 million tonnes, valued at US$250 – US$630 million, says a UK’s Department for International Development commissioned study.
Center for Agriculture Bioscience International (CABI, the parent organisation of SciDev.Net) experts in a study identified 50 such products registered in 30 countries globally and selected 23 which included for safety assessment and accessibility to farmers.
Fall armyworm is an important and challenging pest management target in Africa’ so safe, sustainable and effective interventions such as biopesticides are a ‘key component of management strategies’ to consider over chemical controls, says Melanie Bateman, lead author of the study published in the Journal of Applied Entomology (21 October).
In 2017, the researchers reviewed literature and product labels, profiling active ingredients particularly those in Africa to assess effectiveness of biopesticides against fall armyworm and other armyworms in general.
Analysis of registered pesticides and biopesticides specifically for fall armyworm was conducted in January and February of 2018 in Benin, Burkina Faso, Cameroon, Democratic Republic of Congo, Ethiopia, Ghana, Kenya, Mali, Malawi, Mozambique, Nigeria, Rwanda, Sierra Leone, South Africa, Tanzania, Togo, Tunisia, Uganda and Zimbabwe.
In general, biological pesticides are safer to humans and the environment than synthetic chemicals, says Roger Day, programme executive, Action on Invasives at CABI.
“This is particularly important in Africa where farmers often use dangerous chemicals without the necessary safety equipment, due to their resource limitations,” he tells SciDev.Net.
Elizabeth Bandason, insect scientist based at Bunda College of Agriculture, University of Malawi, says that biopesticides are a viable control method compared to chemical control.
“They degrade from the environment at a faster rate than the chemical pesticides,” she says.
However, the potential of biopesticides to curb the fall armyworm menace comes at a price for smallholder farmers, says Jean Baptiste Bahama, crop production and protection officer at the UNs’ Food and Agriculture Organization in Ghana.
The problem is that the purchasing power of farmers is very low, Bahama tells SciDev.Net, and biopesticides can cost more than chemical treatments, and can be slower to act.
“The low prices that smallholder maize farmers receive for their products cannot economically justify their use,” he says.
“Most biopesticides, the ones that are easily accessible to the farmers, may work more slowly than expected, so there is a need to improve the existing biopesticide combinations so that they act faster,” Bandason tells SciDev.Net.
Many countries, international research organisations and biopesticide manufacturers have prioritised the identification of low-risk management options for fall armyworm, says Bateman in a statement.
Supporting governments to discuss registration and policy framework for biopesticides use considering the economic context of smallholder farmers could help, suggests Bahama.