The changing status of invertebrate pests and the future of pest management in the Australian grains industry

Abstract

The Australian grains industry is dealing with a shifting complex of invertebrate pests due to evolving management practices and climate change as indicated by an assessment of pest reports over the last 20–30 years. A comparison of pest outbreak reports from the early 1980s to 2006–07 from south-eastern Australia highlights a decrease in the importance of pea weevils and armyworms, while the lucerne flea, Balaustium mites, blue oat mites and Bryobia mites have increased in prominence. In Western Australia, where detailed outbreak records are available from the mid 1990s, the relative incidence of armyworms, aphids and vegetable weevils has recently decreased, while the incidence of pasture cockchafers, Balaustium mites, blue oat mites, redlegged earth mites, the lucerne flea and snails has increased. These changes are the result of several possible drivers. Patterns of pesticide use, farm management responses and changing cropping patterns are likely to have contributed to these shifts. Drier conditions, exacerbated by climate change, have potentially reduced the build-up of migratory species from inland Australia and increased the adoption rate of minimum and no-tillage systems in order to retain soil moisture. The latter has been accompanied by increased pesticide use, accelerating selection pressures for resistance. Other control options will become available once there is an understanding of interactions between pests and beneficial species within a landscape context and a wider choice of ‘softer’ chemicals. Future climate change will directly and indirectly influence pest distributions and outbreaks as well as the potential effectiveness of endemic natural enemies. Genetically modified crops provide new options for control but also present challenges as new pest species are likely to emerge.

Strategic tillage in no-till farming systems in Australia’s northern grains-growing regions: II. Implications for agronomy, soil and environment

“…This can considerably reduce reliance on insecticides thereby lowering the risk of developing insecticide resistance in the pest population. Changing tillage systems, such as the adoption of NT to retain soil water and maintain soil structure, can lead to new pest pressures (Hoffmann et al, 2008). Black field earwigs (Nala lividipes), for example, prefer tilled soil rather than undisturbed soil (QDAFF, 2012), and so the move toward NT has been useful.…”

Genetic Markers Indicate a New Species Complex of Emerging Pest Mites in Australian Grains

“…Balaustium medicagoense Meyer & Ryke (Acari: Erythraeidae) and Bryobia spp. Koch (Acari: Tetranychidae) are newly emerging pests of winter crops and pastures, whose importance within the Australian grains industry has increased in the past decade (Hoffmann et al 2008b). However, their economic impact and pest status within Australia is currently unknown and difÞcult to assess as they are often misidentiÞed for each other and other pest mites, including the mites Halotydeus destructor (Tucker) and Penthaleus spp.…”

“…The relative importance of invertebrate pests within the Australian grains industry have changed in recent times due to shifting agronomic practices and climatic conditions (Hoffmann et al 2008b). Balaustium medicagoense Meyer & Ryke (Acari: Erythraeidae) and Bryobia spp.…”

The distribution, abundance and life cycle of the pest mites Balaustium medicagoense (Prostigmata: Erythraeidae) and Bryobia spp. (Prostigmata: Tetranychidae) in Australia

“…in the past decade . The reason for the increasing importance of these mites is still unknown; however, misidentification, increased awareness, climate change, high pesticide usage and/or changing agricultural practices may all contribute (Arthur et al 2008;Hoffmann et al 2008).…”