Strategies and tactics for herbicide use reduction in field crops in Canada: A review

Abstract

There are many economic and health reasons for reducing pesticide use in Canada. Herbicide use on field crops is by far the most common pesticide use in Canada. This paper is a review of four topics related to herbicide use reduction on field crops in Canada: (1) broad strategies and (2) specific tactics for herbicide use reduction; (3) factors affecting adoption; and 4) research approaches for improving the implementation of herbicide use reduction. Numerous tactics exist to use herbicides more efficiently and herbicides can sometimes be replaced by non-chemical weed control methods. Many of these tactics and methods have been investigated and demonstrated for use on field crops in Canada. However, herbicide use reduction is fundamentally dependent upon preventative strategies designed to create robust cropping systems that maintain low weed densities. Diverse crop rotation forms the basis of preventative strategies as it inherently varies cropping system conditions to avoid weed adaptation. There is evidence that residual weed densities resulting from herbicide use reduction are manageable within competitive cropping systems. A great deal of research has been done on herbicide use reduction on field crops in Canada, and most projects report definite possibilities for herbicide use reduction in field crop production in Canada. Synthesizing and extending this information and customizing it for use on individual farms remain challenges. Collaboration between researchers and farmers can help to build successful strategies for herbicide use reduction which reflect the context of modern farming, the will of farmers and the culture of technology adoption among farmers. Key words: Pesticide use reduction, low-input agriculture, integrated pest management, integrated weed management

Controle de papuã (Brachiaria plantaginea) em soja em função da dose e da época de aplicação do herbicida clethodim

“…Nesse aspecto, muitas vezes, com a integração de práticas de manejo, as doses de herbicidas podem ser reduzidas e, ainda assim, prover controle satisfatório dessas plantas (Mohler, 2001;Nazarko et al, 2005). Uma prática importante a considerar na adoção do manejo cultural de plantas daninhas refere-se à redução do espaçamento entre fileiras da cultura.…”

The Sustainability of Organic Grain Production on the Canadian Prairies—A Review

“…Increasing seeding rates has been shown to be an effective strategy for enhancing crop competitiveness in integrated weed management systems [39,40], or other reduced input systems aiming to decrease herbicide use [41]. O'Donovan et al [42], found that increasing barley crop densities enhanced the effectiveness of the herbicide tralkoxydim on wild oats, allowing for reduced application rates.…”

Integrated weed management systems with herbicide-tolerant crops in the European Union: lessons learnt from home and abroad

“…[35,43] Several studies have demonstrated that this tactic can maintain effective weed control and sustain economically acceptable crop yields. [44,45] Conflicting results regarding success in using reduced herbicide rates may be due to a variety of factors such as spray volume, droplet size, adjuvants, temperature, humidity, light quality, soil moisture content, weed size and weed species.…”

“…tank mixes of postemergence herbicides with different modes of action). [35,41] Therefore, the choice of suitable herbicides should also take into account other factors affecting weed resistance evolution such as the frequency, number, dominance and fitness of genes conferring resistance to an herbicide.…”

“…[27,33,34] Diversification in crop systems and weed management tactics reduces the risk of weeds evolving herbicide resistance(s) and promotes biodiversity. [35] Therefore, the most effective and sustainable use of HT crops would be as a component of an integrated weed management (IWM) approach. IWM advocates the use of multiple strategies or tactics to manage weed populations in a manner that is economically and environmentally sound.…”