For West African mango growers, a small pest is the biggest enemy: the fruit fly. Since the arrival of Bactrocera dorsalis—a highly invasive species of fruit fly native to Asia—in 2005, mango growers have lost over 50 percent of their orchards by the middle of the season each year. As the fruit ripens later in the crop season, losses increase, resulting in less income loss for the growers.
With assistance from the West and Central African Council for Agricultural Research’s (CORAF) Project to Support the Regional Plan for the Control of Fruit Flies in West Africa, mango growers not only limit their harvest losses, but also increase their production of mangoes for export. With the project’s aid, growers receive training on, collaborate over, and gain access to an Integrated Pest Management (IPM) package—an environmentally sensitive approach to pest management that gathers several trusted techniques from the region. “Most of the pesticides currently used are ineffective and damage public health, ecological sustainability, and farming system resilience,” says Dr. Mame Farma Ndiaye Cissé, Project Coordinator at CORAF. The project, however, “will positively impact the level of life of producers.”
Food Tank interviewed Cissé about the project’s unique IPM package, bringing the global market for mangoes closer to growers in West Africa to improve their lives.
Food Tank (FT): What do you find most exciting about the work that Project to Support the Regional Plan for the Control of Fruit Flies in West Africa is doing?
Dr. Mame Farma Ndiaye Cissé (FC): The main objective of the project is to increase the amount of exports from involved countries. This will positively impact the level of life of producers. This objective, as a whole, is a very exciting one to realize, as it requires developing new and accessible products against fruit flies, training producers, organizing them, and setting up and facilitating collaboration between different structures in the mango value chain.
FT: Why is controlling fruit flies an important issue in West Africa?
FC: Due to the invasive fruit fly Bactrocera dorsalis, which spread to 19 Sub-Saharan African countries since 2005, mangoes are most threatened by fruit flies. Fruit flies are quarantine pests and caused a ban and a restriction on imports to the United States and European Union, respectively. Fruit producers cannot access valuable export markets until these pest problems are solved. The capacity of West African exporters to be competitive and access foreign markets depends mainly upon their ability to sustain a reliable supply of fruits which meet increasingly stringent quality and safety standards. Fruit flies affect the mango’s quality and disqualify products for exports, making this supply unreliable.
In Africa, fruit producers lack access to appropriate pest control methods. Small-scale producers try to avoid fruit fly infestation by picking fruit early before it matures, yet even after doing so, pest damage can still be significant. Other producers use pesticides intended for cotton production or sometimes even import bait sprays. As a consequence, most of the pesticides currently used are ineffective and damage public health, ecological sustainability, and farming system resilience.
FT: What is integrated pest management, and how has the project built upon this approach?
FC: Our IPM package includes: 1) prophylactic methods, or methods to contain infestation including gathering and discarding the fallen fruits; 2) bait sprays or GF-120 consisting of leaf sprays of all orchard trees; 3) weaver ants and the chemical they produce that wards off fruit flies, referred to as weaver ant husbandry; 4) mass traps reducing the population of fruit flies, especially male, by attracting them and killing them with insecticide; and 5) bio-control with parasitoids, which are insects that lay their eggs inside other insects, eventually killing them.
The project improves West African mango growers’ access to effective and efficient options for fruit fly management. We have built upon this approach through Innovation Platforms, which are efforts that include local partner institutions, stakeholders and producers, and extension workers in developing IPM. This group expands our IPM package in several ways, including by providing training materials for future sustainable producers training in the participant countries. In the same vein through parallel trainings, those contributing to the IPM build their skills and capacity by developing communication materials for farmers.
FT: How does the project monitor the fruit fly infestation rate?
FC: The project has five components, including monitoring on one end and applied research, which includes some monitoring, on the other.
The monitoring component includes a monitoring system based on our model of a “monitoring orchard.” In each country, we install traps at a select number of orchards. We then regularly count the number of flies caught in the traps and report this to the coordinator of the component.
The method of applied research includes an elaborate monitoring system: infestation rates are assessed by sampling and incubating fruits. During the mango’s maturation period, we collect a sample of 40 randomly picked mangoes from the innermost six trees in an orchard every two weeks. In the laboratory, we collect data on each of the mangoes before placing them in jars filled with five centimeters of wet sand. Once a week, fly pupae are collected from the sand and counted to determine the level of infestation. The pupae are checked every three days to collect adults. All the fly species are identified and researched in the laboratories.
FT: What methods for fruit fly control have been the most successful so far?
FC: The most effective control method so far could be the bait spray GF 120. It is an effective and environmentally safe alternative to traditional bait sprays (containing dangerous insecticides) for the control of several fruit flies. GF-120 Fruit Fly bait is a mixture of spinosad (a natural insecticide made from soil bacterium) and food composed of various compounds to attract pests. The adult insects are attracted by the food and killed by the spinosad. However, this method of control overlooks one step of the fruit fly life cycle: the stages from egg laying to adult hatching, wherein new populations of fruit flies establish themselves. Until now, no single method for these pests has been able to guarantee sustainable control of fruit flies throughout all stages of the fly’s life. It is therefore crucial to introduce a combination of effective and efficient methods, which must be mutually compatible and economically viable if they are to be adopted by planters.
FT: What are some of the biggest challenges facing effort to control fruit flies in the region?
FC: A recent field survey revealed that for fruit crop value chains (mango especially), sanitary problems related to fruit flies constrained main production most, resulting in low yields, according to stakeholders. Stakeholders expressed the need for basic knowledge on pest damage and skills to control those pests. Producers in West Africa requested access to effective control strategies and training to use them safely and efficiently. It is therefore important to develop pest management strategies that compromise neither public health nor the environment.
Our IPM package has been developed and implemented as a research and development tool on-farm in a number of agro-ecological zones in eight countries: Benin, Burkina Faso, Côte d’Ivoire, Ghana, Guinea, Mali, Senegal and Togo. Producers involved in the on-farm research refrained from using insecticides to control fruit flies. However, this behavior may end after the project ends. A possible way to respond to this is through conducting research and facilitating learning in particular to solve the issue of fruit flies for the long-term.