Comparative Screening of Mexican, Rwandan and Commercial Entomopathogenic Nematodes to Be Used against Invasive Fall Armyworm, <i>Spodoptera frugiperda</i>
Patrick Fallet,
Lara De Gianni,
Ricardo A. R. Machado,
Pamela Bruno,
Julio S. Bernal,
Patrick Karangwa,
Joelle Kajuga,
Bancy Waweru,
Didace Bazagwira,
Thomas Degen,
Stefan Toepfer,
Ted C. J. Turlings
Affiliations
Patrick Fallet
Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland
Lara De Gianni
Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland
Ricardo A. R. Machado
Experimental Biology Research Group, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland
Pamela Bruno
Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland
Julio S. Bernal
Department of Entomology, Texas A&M University, College Station, TX 77840, USA
Patrick Karangwa
Rwanda Agriculture and Animal Resources Development Board (RAB), KG 569 Street, Kigali 5016, Rwanda
Joelle Kajuga
Rwanda Agriculture and Animal Resources Development Board (RAB), KG 569 Street, Kigali 5016, Rwanda
Bancy Waweru
Rwanda Agriculture and Animal Resources Development Board (RAB), KG 569 Street, Kigali 5016, Rwanda
Didace Bazagwira
Rwanda Agriculture and Animal Resources Development Board (RAB), KG 569 Street, Kigali 5016, Rwanda
Thomas Degen
Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland
Stefan Toepfer
CABI, Rue des Grillons 1, CH-2800 Delémont, Switzerland
Ted C. J. Turlings
Laboratory of Fundamental and Applied Research in Chemical Ecology, Institute of Biology, University of Neuchâtel, Rue Emile-Argand 11, CH-2000 Neuchâtel, Switzerland
The fall armyworm (FAW), Spodoptera frugiperda Smith (Lepidoptera: Noctuidae) is an important pest of maize originating from the Americas. It recently invaded Africa and Asia, where it causes severe yield losses to maize. To fight this pest, tremendous quantities of synthetic insecticides are being used. As a safe and sustainable alternative, we explore the possibility to control FAW with entomopathogenic nematodes (EPN). We tested in the laboratory whether local EPNs, isolated in the invasive range of FAW, are as effective as EPNs from FAW native range or as commercially available EPNs. This work compared the virulence, killing speed and propagation capability of low doses of forty EPN strains, representing twelve species, after placing them with second-, third- and sixth-instar caterpillars as well as pupae. EPN isolated in the invasive range of FAW (Rwanda) were found to be as effective as commercial and EPNs from the native range of FAW (Mexico) at killing FAW caterpillars. In particular, the Rwandan Steinernema carpocapsae strain RW14-G-R3a-2 caused rapid 100% mortality of second- and third-instar and close to 75% of sixth-instar FAW caterpillars. EPN strains and concentrations used in this study were not effective in killing FAW pupae. Virulence varied greatly among EPN strains, underlining the importance of thorough EPN screenings. These findings will facilitate the development of local EPN-based biological control products for sustainable and environmentally friendly control of FAW in East Africa and beyond.
