Nanocomposite based slow release atrazine effectively controlled Striga asiatica incidence, and enhanced sugarcane yield

Sugarcane is a major industrial crop highly susceptible to parasitic weed (Striga spp.), causing a 38% reduction in cane yield due to a longer lag phase of 20-40 days, and wider spacing. Herbicides with a longer retention and slow-release nature could allow Striga seeds to germinate and be killed before attaching to the host. Therefore, a graphene oxide based nanoformulation loaded with atrazine was synthesized and evaluated under controlled and field conditions for its release kinetics, Striga control efficiency (SCE), and cane yield for two years (2018-2019) at two locations. In-vitro assays on release kinetics showed that the release rate of active ingredient (a.i.) from the nanocomposite loaded with atrazine (NCA) was slower (64.5%) than conventional atrazine (82.1%) on the 30th day in water. Similarly, cumulative release percentage of a.i. with NCA was 4.4% compared to atrazine (16.2%) at the initial 0-3 days in soil. Further, field evaluation (deep application in 12 cm furrows) of NCA at 1.25 kg a.i./ha at 95 days after planting (DAP) found superior in delaying Striga emergence by 18-20 days over atrazine. Furthermore, NCA recorded the highest efficacy (∼ 21%) across two locations owing to reduced Striga density (66.7-68.2%) and dry weight (39.3-48.9%). Consequently, NCA at 95 DAP produced higher cane (30.6-31.0%) and sugar (30.7-36.7%) yields. Therefore, carbon-based graphene oxide with a greater surface area and low production cost would offer an environmentally benign and alternative option in controlling Striga before its haustorium attaches to sugarcane roots. This formulation represents a novel direction for developing herbicides with enhanced performance and reduced environmental impact.