Understanding Mechanisms of Herbicide Selectivity in Agro-Ecosystems: A Review

Abstract

Weeds cause yield losses in desired crops through competition for sunlight, water, space, and nutrients. It is important to manage weeds in crop fields and aqua bodies using various management strategies. One of the most effective and efficient ways of managing weeds is through the use of herbicides. However, there is a need to understand the effects of these herbicides on the desired plants and/or the environment. Herbicide selectivity allows the application of herbicides in a field with both the desired crop and weeds. Herbicide selectivity is therefore described as, an application treatment at a given dosage that is toxic to some plant species but does not damage another species. However, many herbicides can be toxic at high dose rates even when applied to tolerant crops. There are several mechanisms of herbicide selectivity which are grouped into physiological and physical. Physical herbicide selectivity occurs when physical factors such as time, the position of application, plant morphological structure, and environment aid in selectivity. Physiological selectivity occurs when the plant species affect herbicide retention, penetration, movement, and detoxification. Herbicide selectivity is known to be a major cause of difficulties in controlling weeds. As a result, there is a need to understand how the environment, herbicides, and plants contribute to selectivity. This paper, therefore, provides insights into herbicide selectivity and how plants escape herbicide injury which enables species diversity.

Assessment of herbіcіde effіcacy, phytotoxіcіty and economіcs іn soybean (Glycіne max L. Merrіll)

“…Thіs posіtіve outcome can be attrіbuted to the precіse dosage of bentazone herbіcіde whіch resulted іn a reduced productіon of reactіve oxygen specіes. Thіs reductіon, іnturn decreased the relіance on soybean antіoxіdant enzyme actіvіty, ultіmately leadіng to hіgher yіelds (Justіn et al, 2023) [9] .…”

Physiological Basis for the Mechanism of Selectivity of Tripyrasulfone between Rice (Oryza sativa) and Barnyard Grass (Echinochloa crus-galli)

“…Generally, herbicide selectivity is defined as the ability of some plant species to withstand a given herbicide dose, while others are killed at the same dose. 27 Herbicide selectivity can be roughly divided into two forms, namely, physiological and physical mechanisms. 28 The physical herbicide selectivity includes the position selectivity, application device selectivity of nonselective herbicides, chronological selectivity, morphological selectivity (between grass and broadleaf weeds), and some physical forms of soil properties, prevailing climatic conditions, leaf orientation, and plant stage of growth.…”

“…Meanwhile, the physiological herbicide selectivity results from differential herbicide penetration, translocation and metabolism in the plants, compartmentalization/sequestration, and altered binding sites and utilization of safeners. 27,29,30 HPPD-inhibiting herbicides have been used for years, although there have been limited reports on the selective mechanism in rice. 31 Tripyrasulfone is an efficacious HPPDinhibiting POST herbicide against annual weeds in directseeded rice, and further research is warranted to identify the mechanisms associated with its high selectivity between rice and grass weed species.…”

“…The physical herbicide selectivity includes the position selectivity, application device selectivity of nonselective herbicides, chronological selectivity, morphological selectivity (between grass and broadleaf weeds), and some physical forms of soil properties, prevailing climatic conditions, leaf orientation, and plant stage of growth. Meanwhile, the physiological herbicide selectivity results from differential herbicide penetration, translocation and metabolism in the plants, compartmentalization/sequestration, and altered binding sites and utilization of safeners. ,, …”

“…Generally, herbicide selectivity is defined as the ability of some plant species to withstand a given herbicide dose, while others are killed at the same dose . Herbicide selectivity can be roughly divided into two forms, namely, physiological and physical mechanisms .…”