Evaluation of formulated strigolactone analogs for Striga management in Kenyan agriculture

Striga hermonthica, an obligate root parasitic weed affecting cereal crops, poses a significant threat to global food security in Sub-Saharan Africa (SSA). Germination of Striga seed largely relies on signaling molecules released by the host roots, mainly strigolactones (SLs). Suicidal germination is an effective strategy for reducing Striga seed banks in infested soils by applying SL analogs in the absence of a host. However, the challenge remains in developing suitably formulated SL analogs for field application. In this report, we assessed the activity of two SL analogs, MP3 and Nijmegen-1, in both granular and liquid formulations in laboratory and greenhouse settings, and conducted mini-field and field trials to evaluate their effectiveness under farmers' conditions, using maize as the host crop in Kenyan agriculture. We observed a significant induction of Striga seed germination reaching up to 56 % in laboratory germination bioassays and a reduction in Striga emergence by up to 77 % in greenhouse pot studies. In mini- and field trials in different infested fields, we recorded up to 80 % and 65 % reduction in Striga emergence, respectively. In conclusion, the formulated SL analogs demonstrate significant potential to reduce Striga infestation in maize fields in Kenya and are promising candidates for use by farmers due to their simplicity, ease of handling, stability, and effectiveness.