A bibliometric analysis of herbicide resistance in Africa

Abstract

Herbicides were introduced in the 1950s, and since then, there has been an increase in herbicide-resistant weeds. This is apparent from the multiple (503) literature reviews on herbicide resistance worldwide. In Africa, there are few, if any, reviews on herbicide-resistant weeds, even though herbicide-resistant weeds affect sustainable agriculture by decreasing the quantity and quality of food production. In this study, articles sourced from the Scopus database were reviewed. Articles related to herbicide resistance, with a special emphasis on articles that applied herbicides to weeds and investigated the mechanisms of said resistance, were included. The results showed that there was multiple collaboration between Kenya, South Africa, Ethiopia, France, the USA, Spain, Italy, and Germany to elucidate the mechanisms of resistance and weed control strategies. Numerous keywords of interest, such as Lolium, glyphosate, and acetolactate synthase (ALS), appeared consistently in the literature. There are a total of 14 weed species (six monocots and eight dicots) in Africa that are resistant to six of the 31 known sites of action. Out of the 54 countries, only five have reported herbicide-resistant weeds. Resistance was due to target-site and non-target-site resistance mechanisms. However, one monocot (Lolium rigidum) and two dicots (Glebionis coronaria and Plantago lanceolata) from Tunisia and South Africa that are resistant to ALS and photosystem I inhibitors were not reported on the International Survey of Herbicide-Resistant Weeds database. Urgent weed control strategies are needed to stop the spread of resistance alleles. However, no one strategy will be effective unless a diversified approach, such as integrated weed management (IWM), is adopted to curb the spread of resistance alleles.