Integrated pest management (IPM) strategies for greenhouse hydroponic production of berry crops

The berry industry in Australia is currently experiencing significant growth under greenhouse hydroponic production systems. Growers of the main berry types (strawberries, raspberries, blackberries and blueberries) have attempted to modify the growing environment through the investment of protective cropping structures and systems to achieve increased yields and quality of berry fruit. In a controlled environment, it is also possible to target production windows not possible through conventional outdoor, soil-based berry cultivation.

The manipulation of, and adjustment in, climatic conditions within a greenhouse production system has provided consistency and stability for berry crop growth and development. Inadvertently, this has created a suitable environment for pest and disease establishment and infestation. An increase in supermarket demands for minimum quality standards regarding berry fruit presentation, durability and maximum residue levels has created further pressure on growers. Coupled with the lack in options for chemical control products it would appear that the adoption of Integrated Pest Management (IPM) strategies would be beneficial.

IPM is a common sense, proactive approach to crop protection demanding attention to monitoring and scouting; identification of the pathogen; recording of data and forecasting to determine economic thresholds. An informed decision can then be made on time of intervention and methods of crop protection control.

A range of controls including physical, cultural and biological based options should be considered before reverting to chemical controls, where possible. Within the biological based options, there are a number of arthropod biological control agents including predators and parasitoids, as well as entomopathogenic nematodes. Each of these beneficials are either host specific or generalist in their pest targets, but performance maybe adversely impacted by climate conditions, day length and population levels.

Additionally, there are biological chemicals which are either specifically orientated towards disease control or insect pest control. These biological chemicals fall into a number of different groups, with variations in their mode of action. Mycorrhizae form a symbiotic relationship between a fungus and the roots of a plant. They assist with nutrient uptake as well as provide protection for both abiotic and biotic stress.

Entomovectoring is a concept where pollinating insects are utilised to disseminate beneficial microbial controlling agents to target crops. Bumble bees have been commercially applied to greenhouse crops for the purpose of effective pollination. More recently, they have been utilised for entomovectoring on a commercial application in greenhouse hydroponic berry production systems. Unfortunately, bumble bees are forbidden on mainland Australia and therefore honeybees are the next possible vector.

The intention of the author was to explore and assess IPM strategies globally and to then identify emerging and innovative technologies available for commercial application in the greenhouse hydroponic berry industry in Australia.