The larvae use chemical compounds emitted by plants to locate roots. Growers rely mainly on synthetic insecticides, covers and plant resistance.
One of the problems facing brassica growers is the withdrawal of organophosphate insecticides. Alternative treatments are limited, so new strategies are urgently sought.
Plant-derived extracts, marketed as plant stimulants, have the potential for activity if applied to the soil as a drench at the time of egg hatch. They contain chemicals that will affect the behaviour of cabbage root fly.
PhD student William Deasy at Scottish Agricultural College aims to develop a novel management strategy based on attractant and repellent compounds, plant extracts and sugar inducible defences for disrupting host plant location. This will be evaluated in field trials. Treatments will include soil-applied slow-release granular formulations, seed coatings, foliar/soil sprays or treated plugs for transplants.
The first step is to identify compounds excreted by broccoli and Chinese cabbage roots that influence larval behaviour. Then, larval responses to different concentrations of liquid mustard formulation will be studied, and the potential of sugars to trigger inducible defence responses in Brassicas.
The most promising treatments will be used in trials. The summary for FV 364 is available on the HDC website at www.hdc.org.uk.
Date for your diary
15 February HDC/LGA Leek Agronomy Day, Norfolk.
Horticultural Development Company
For details on all HDC activity, visit www.hdc.org.uk