Biopesticide research and product development in Africa for sustainable agriculture and food security
−− Experiences from the International Centre of Insect Physiology and Ecology (icipe)
Nov. 6, 2020
By Komivi Senyo Akutse, Sevgan Subramanian, Nguya Kalemba Maniania, Thomas Dubois and Sunday Ekesi
Arthropod pests and vectors constrain the livelihood opportunities of people in Africa by debilitating production of crops and livestock and through transmission of vector-borne diseases. In the absence of effective alternative management options to tackle these pests and vectors, there is extensive dependence on synthetic pesticides for their management on crop and livestock systems, with significant negative impacts on animal and human health, and the environment.
Biopesticides are effective and environmentally sustainable alternatives to synthetic pesticides. At the International Centre of Insect Physiology and Ecology (icipe), the Arthropod Pathology Unit (APU) was established for effective biopesticide research-for-development (R4D), underpinned by a large repository of arthropod pathogens, protocols for lab bioassays and field efficacy testing, and an effective public-private partnership to generate new biopesticide products. The focus of icipe's APU has gradually transformed from basic to applied research leading to innovative, commercial products. Among the insect pathogens, greater focus has been placed on fungi, especially Metarhizium anisopliae, against key crop and livestock pests. Presently, three biopesticides based on M. anisopliae strains researched by icipe have been commercialized by Real IPM (Thika, Kenya) and are used on 132,994 ha in sub-Saharan Africa, with registration of additional products against animal ticks and the fall armyworm Spodoptera frugiperda pending.
Biopesticide Use in Africa
In Africa, biopesticide use is still at its infancy and only accounts for 3% of the world biopesticide market, although little information is available on adoption rates of biopesticides on the continent (Olson, 2015). Although several biopesticides are registered in countries across Africa, few are developed on the continent itself (Grzywacz et al., 2019). However, changes are occurring, with South Africa and Kenya leading in biopesticide development and use. In South Africa, of the 31 products registered, seven are locally produced, mainly based on Beauveria bassiana (Hatting et al., 2019). A major supplier of biopesticides in Africa is Real IPM, which has marketed four strains from icipe (Metarhizium anisopliae strains ICIPE 69, 78, 62 and 7). Between 2015 and 2019, use of Real IPM's entomopathogenic fungi-based products has increased more than 3-fold from only 43,290 ha in 2015 to 132,980 ha in 2019 (figure below). Products based on M. anisopliae strain ICIPE 69, which target mealybugs, thrips, leafminers and fruit flies, constitute the largest African portfolio, the use of which increased the fastest, from 19,370 ha in 2015 to 80,420 ha in 2019, a more than 4-fold increase.
Biopesticide Research as a Function of Targets (Plant Pests)
A plethora of polyphagous indigenous and invasive pests, such as whiteflies, leafminers (Liriomyza sp.), cereal stemborers (C. partellus and Busseola fusca), the diamondback moth Plutella xylostella, the African bollworm Helicoverpa armigera, the red spider mite Tetranychus urticae, the tomato spider mite Tetranychus evansi, aphids, thrips, fruit flies, pod borers, pod suckers, storage beetles, the false codling moth Thaumatotibia leucotreta and, recently, the fall armyworm Spodoptera frugiperda and the tomato leafminer Tuta absoluta significantly reduce sustainable production of staple and horticultural crops, and consequently inflict enormous economic losses. In addition, some insects are vectors of serious plant diseases (e.g., thrips, whiteflies and the cowpea aphid Aphis craccivora).
icipe has actively engaged in research to identify virulent entomopathogens of these pests, with a greater emphasis on entomopathogenic fungi belonging to the genera of Metarhizium sp. and Beauveria sp. Strains belonging to this genus are relatively easy to mass-produce, formulate and apply, and were found to be among the most virulent against Africa's pests. Longstanding research has yielded significant results, and currently, three fungal products based on M. anisopliae strains ICIPE 69, ICIPE 78 and ICIPE 62 are commercialized for management of key pests in several countries in sub-Saharan Africa as well as Canada. Currently, screening efforts are expanding beyond M. anisopliae toward other entomopathogenic fungi such as B. bassiana and Isaria fumosorosea, bacteria, microsporidia, nematodes and viruses. A recent research thrust centers on endophytes such as Hypocrea lixii and Trichoderma sp.
Based on long-standing experience in developing M. anisopliae into biopesticides, the time taken from identification of virulent strains to commercialization as biopesticide products has considerably shortened. This is attributed largely to more efficient R4D related to product development, better interactions with regulatory authorities and policy makers, and stronger engagement with the private sector and partnership arrangements to identify market needs. For example, whereas it took >15 years from the first screening of M. anisopliae strain ICIPE 69 to development into the commercial product Real Metarhizium 69, we estimate that duration between first screening of M. anisopliae strain ICIPE 7 for S. frugiperda to commercialization is likely to take only 36 months. Faster biopesticide development is crucial to tackle biological control against emerging pests such as S. frugiperda, T. absoluta and the desert locust Schistocerca gregaria.
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