Influence of reduced irrigation on beneficial invertebrates in vineyards

Abstract

An important aspect of increasing the sustainability of agricultural production in dry continents such as Australia is decreasing water use. In this study full irrigation is compared with partial rootzone drying, a method that uses targeted controlled watering to reduce water use while maintaining production in vineyards. The impact of the 2 irrigation methods on invertebrates with potential to influence productivity (pests, predators, parasitoids and soil macroinvertebrates) in a vineyard in south-eastern Australia is also investigated. Invertebrates were sampled at ground level and in the canopy using 3 methods: pitfall traps and 2 types of sticky trap. Earthworms were sampled by hand sorting soil. Initial sorting of the collections was to the order level. The implementation of partial rootzone drying throughout the growing season (December–March) over 2 consecutive years had little effect on the invertebrate orders analysed. Only 2 generalist predator orders (Araneae and Coleoptera) and earthworms (Haplotaxida) were significantly affected under conditions of water stress. These data suggest that reduction of irrigation of the magnitude required for partial rootzone drying has limited consequences for natural enemies of vineyard pests and soil macroinvertebrates in the short term.