Interactions between weeds, arthropod pests, and their natural enemies in managed ecosystems

Abstract

Interactions between weeds and arthropods occur frequently. This review covers the topic of weed/arthropod interactions, and provides the reader with access to literature in the subject area that is scattered in weed science, entomological, crop production, and ecological journals. We first analyze the current status of weed and arthropod management in the context of multidisciplinary integrated pest management (IPM). The remainder of the review is organized according to the mechanisms driving interactions. The first section deals with interactions driven by trophic relationships, and is subdivided into direct and indirect trophic interactions. Direct trophic interactions occur when pest or beneficial arthropods feed directly on weeds. Indirect trophic interactions occur when arthropod feeding damage to crops impacts weeds through alteration of ecosystem resource availability, or through weeds serving as hosts for alternate prey for beneficial arthropods, or via tritrophic interactions. The second mechanism driving interactions is considered in relation to alteration of the physical habitat by the presence of weeds, such as alteration of temperature within the plant canopy. The third major mechanism driving interactions is based on control tactics for the two types of pests. These are considered from the aspect of direct physical effects, such as tillage, and from the aspect of interactions resulting from the use of pesticides. The latter is divided into direct effects of herbicides and insecticides on non-target pests and beneficials, and on interactions that result from alteration of host plant physiology by pesticides. A conclusion section attempts to place the impact of interactions into an IPM framework, and to indicate where multidisciplinary research involving weed and arthropod management should be focused in the future.

Responses of plants and invertebrate trophic groups to contrasting herbicide regimes in the Farm Scale Evaluations of genetically modified herbicide–tolerant crops

“…Weeds, by contrast, support a wider range of invertebrate species at lower densities through the provision of a variety of food resources and a more heterogeneous habitat structure (Root 1973;Stinson & Brown 1983; Andow 1991; Norris & Kogan 2000;Haddad et al 2001). Existing evidence (e.g.…”

Impact of Weed Management Practices on Grapevine Growth, Yield Components, Plant and Arthropod Abundance, and Carabid Seed Predation in Paso Robles Vineyard

“…Generally, plant diversity is considered one of the major ecosystem components favoring arthropod diversity (Norris and Kogan, 2000). It is important to mention that due to the strong relationship between plant diversity and density observed in the present study, it is not possible to clearly determine which parameter was more important to promote arthropod diversity.…”

“…Conversely, managing weeds can alter vegetation community and affect microenvironment variables in the ecosystem (Norris and Kogan, 2000), which in turn can change the arthropod community compositions and the functioning of ecological processes (Marshall et al, 2003).…”

“…The goal of habitat management is, therefore, to create a suitable ecological infrastructure within the agricultural landscape to provide resources such as food for natural enemies, alternative prey or hosts, and shelter from adverse conditions. First step toward achieving this goal is to increase the availability of primary producers (plants), because they necessitate the nutrient cycling process in ecosystems and correlate to the functioning of many trophic levels (Norris and Kogan, 2000;Cardinale et al, 2006). Therefore, promoting weed can enhance ecological processes, but must be done so with caution because more vegetation in crop field does not always produce favorable arthropod communities, as shown by a comprehensive review of biodiversity in agriculture ( Straub et al, 2007).…”

“…Besides the negative impact that weeds can have on vine growth, they can create a favourable environment for many organisms including natural enemies of pests (Orr et al, 1997;Aguilar et al, 2003;Marshall et al, 2003). Conversely, managing weeds can alter vegetation community and affect microenvironment variables in the ecosystem (Norris and Kogan, 2000), which can change the arthropod community composition and the functioning of ecological processes (Marshall et al, 2003). Is this bottom-up effect of weed on arthropod occuring in vineyards?…”