The application of pre-emergence herbicides is suitable for weed management in all maize growing areas of Sub-Saharan Africa, especially in farmer communities where availability of labor for manual removal is limited. Studies across the continent have shown that application of pre-emergence herbicides is effective on farmer fields with high to low levels of weed encroachment under humid to semi-arid climates, creating short and long term benefits under these varying conditions. The sort of weeds in farmlands, seasonal weather patterns and timing of other management practices are dictating the exact formulation of chemical agents and moment of application that is necessary for pre-emergence weed killing. Use of the chemical control technology has to be combined with the appropriate input of inorganic fertilizers and organic resources to farmlands for the intervention to increase grain production and food security, especially on degraded fields with low soil fertility status. Pre-emergence weed control strategies have proven to be more effective than post-emergence approaches which are most often used by farmers in Sub-Saharan Africa, thus providing a direct entry point for improving agriculture.

Agro-input companies in Sub-Saharan Africa market a range of pre-emergence herbicides that contain different chemical agents and are designed for eradicating specific kinds of weeds occurring in maize crops. Herbicides for broadleaf weeds such as Blackjack, Thorn Apple, Oxalis and Spiderwort are usually made of atrazine, phenoxy (MCPA) or terbutryn compounds, whereas for grass weeds like Bermuda grass, Guinea Fowl grass, Star grass, Wild oats and Nutsedge the most common herbicides are made of metolachlor, acetochlor or alachlor compounds. Further to this, adjuvants are added to pre-made formulations or spray tanks for enhancing herbicidal activity or application characteristics, such as better mixing and handling, greater droplet coverage, spray retention and droplet drying, improved herbicide cuticle penetration and cellular accumulation which minimize leaching of the chemical agents through the soil profile. Depending on the prevalent sorts of weed and type of maize cultivation, i.e., monocrop, rotation or intercrop, the formulation of pre-emergence herbicide needs to be adjusted.

Concentrated solutions of pre-mixed or single herbicides are diluted in water to activate the chemical agents following the prescribed ratio and safety precautions. This is then applied to farmer fields using a backpack systems with one or two spraying nozzles or tractor-mounted systems with many spraying nozzles, which is substantially benefiting herbicide placement, effectiveness of weed control and labour requirements for application to croplands. Protective clothing should be worn by workers that apply the herbicides to avoid contact with chemical agents. Soils should be moist, not too wet or too dry, when fields are sprayed thus requiring the time of application to be synchronized with rainfall, being carried out one week after tillage of croplands and latest before maize is 10 cm tall. Chemical weed control management technologies should be prioritized on fields with the highest level of weed encroachment and most difficult to control weeds to maximize yield and income gain, allowing to steadily build down infestations on farms.