Plant extracts in agriculture and their applications in the treatment of seeds

Abstract

The harmful effects caused by the use of toxic substances in agriculture have led to the development of alternative solutions, and researchers have focused on understanding the effectiveness and potential of plant extracts in agriculture. The aim of this systematic review was to understand the situation of research and scientific dissemination, as well as how current science has approached the use of plant extracts in agriculture, especially in seed applications. There is potential on the use of plant extracts in agriculture, demonstrated by a high number of publications over the last ten years, especially in the years 2018, 2019 and 2020, and Brazil stands out as the main country on this research area. Control of phytopathogenic microorganisms, insect control, biostimulant effect, resistance induction and herbicide effect have been the main themes explored for use in agriculture. The direct application of plant extracts is centered on plants and seeds, being this latter mainly focused on the control of phytopathogenic organisms and biostimulating effect.

Bio-efficacy of Crude Aqueous Leaf Extracts against the Fall Armyworm (Spodoptera frugiperda) and Maize Ear Rots in Zambia

“…This apparent effectiveness of the R. communis, A. indica and N. tabacum extracts could be attributed to its high contact toxicity effect on the larvae population growth in the first four weeks which overlapped with first and second sprays (see Figure 3) thereby reducing the leaf damage to maize in the early stages of the crop development. Based on performance alone, the use of plant extracts may exhibit varying levels of FAW control, and statistically lower mortality and damage rates compared to synthetic pesticides [26], but may nevertheless be an excellent alternative to synthetic pesticides. Besides being insecticidal, some of these plant leaf extracts like A. indica possess growth promoting substances, hence when applied before anthesis may boost grain yield.…”

“…Several studies have suggested some plant extracts with insecticidal properties are effective and could be used by farmers against FAW [24,25]. However, most of these studies have been conducted either as a laboratory experiment or limited to a single season if it's a field study, as such the uptake of proven plant-based pesticides has remained small and further constrained by limited data on other beneficial aspects [26,27]. The acceptance and adoption of these technologies at the farm level are also hindered by a lack of data on the effectiveness of the farmers' experiential dose rate and spraying regimes and other plant health-related benefits such as reduction in the incidence and severity of maize ear rots.…”