Herbicide Effects on Plant and Insect Communities

Herbicides play a pivotal role in modern agriculture by controlling unwanted vegetation, yet their application extends ecological consequences beyond target weeds. In plant communities, herbicide exposure can reduce species richness, alter functional composition and drive shifts in abundance that cascade through trophic networks. Effects range from acute phytotoxicity and suppressed germination to chronic impacts on flowering time and reproductive success. Insect communities respond both directly, through contact toxicity or systemic uptake in treated plants, and indirectly, via changes in habitat structure, food availability and plant nutritional quality. Altered plant diversity, residual herbicide drift and sub-lethal exposures can disrupt herbivore performance, pollinator services and natural enemy populations. Understanding these dynamics is critical for balancing crop productivity with conservation of biodiversity, sustainable pest management and ecosystem resilience.

Research from Nature Portfolio

Longitudinal field trials in temperate fallow fields have revealed that repeated low-dose applications of widely used herbicides markedly diminish non-target plant species richness and diversity indices, with sub-recommended concentrations sometimes exerting stronger effects than full rates. Experiments on grassland systems demonstrate that broadleaf-selective phenoxy herbicides reduce overall herbivory by generalist grasshoppers yet paradoxically increase insect reproductive output, suggesting complex shifts in resource allocation mediated by altered plant physiology. In paddy-rice ecosystems, both direct mortality of herbivore larvae at application and changes in weed community structure have been shown to shape pest dynamics, highlighting a dual pathway by which herbicide regimes can influence insect abundance and crop-pest interactions.

Herbicide Effects on Plant and Insect Communities publication trend

The graph below shows the total number of articles in herbicide effects on plant and insect communities across all publications each year (not limited to Nature Index journals).

Technical terms

Herbicide drift: Movement of active herbicide particles or vapour beyond the target zone, potentially affecting non-target plants and habitats.

Sub-lethal exposure: Contact or uptake of herbicide doses insufficient to cause immediate death but capable of inducing physiological or reproductive changes.

Non-target species: Plants or animals not intended to be controlled by herbicidal treatment yet impacted through direct toxicity or habitat alteration.

Flowering phenology: Timing and sequence of developmental stages in plant reproduction, including bud formation, anthesis and seed set.

Community composition: The identity and relative abundance of species within an ecological assemblage, often assessed to measure biodiversity.

References

1. Effects of herbicides on non-target plant species diversity and the community composition of fallow fields in northern China. Scientific Reports (2020).
2. Direct and indirect effects of plant diversity and phenoxy herbicide application on the development and reproduction of a polyphagous herbivore. Scientific Reports (2020).
3. Direct and Indirect Effects of Herbicides on Insect Herbivores in Rice, Oryza sativa. Scientific Reports (2019).
4. Sub-lethal glyphosate exposure alters flowering phenology and causes transient male-sterility in Brassicaspp. BMC Plant Biology (2014).
5. Dicamba drift alters plant–herbivore interactions at the agro‐ecological interface. Ecosphere (2022).