2014-01-29   facebook twitter rss

New Soil Research - Adding Good Bugs to Oust the Bad

SRUC and the Irish Agriculture and Food Development Authority (Teagasc), have begun a research project that will help growers and gardeners improve their soil by encouraging beneficial soil organisms.

They hope to show that with appropriate soil management brassica plants will be better protected from cabbage root fly.


photo: freebigpictures.com

Soils are filled with micro organisms and bacteria, some of which enjoy eating those bugs that strike fear into the heart of all vegetable growers, whether they have a small bed in the back garden, or hundreds of hectares. This project aims to identify and increase the number of organisms in the soil that will target the cabbage root fly, which causes widespread damage throughout the UK and Ireland.

With the implementation of the Sustainable Use of Pesticides Directive from January 1, development of strategies such as these will become more important as growers implement Integrated Pest Management strategies in field vegetable crops. Growers who try to avoid chemicals often find their crops decimated by insects.

However this new research – funded by Teagasc and the Horticultural Development Council – could make that a less common experience. The team will study how to enhance the properties of soils, looking specifically at those used to grow field vegetables, such as broccoli and cabbage.

SRUC’s Professor Bryan Griffiths, says: “While commercial growers can use chemical methods to help control cabbage root fly, they still face significant losses each year. Many growers would prefer not to have to use chemical pesticides and are also very interested in maintaining and increasing soil health and are continually searching for alternative pest control options.

Improving soil quality is crucial for all growers of crops as a way of preventing crop damage or even death. This research will hopefully give both commercial growers and the public options to improve their soils which will in turn mean healthier plants.”

For commercial growers, it is estimated that without adequate insecticidal control about 24% of field brassica crops would be rendered unmarketable by the cabbage root fly.

Even if cultural methods – such as the use of crop covers – could be relied on to lower overall damage to 15-20%, the industry is still facing losses of about £40m per annum from the area of crop that needs protecting against attacks by the cabbage root fly.

Cabbage root fly maggots eat the roots of brassica plants and this is only noticeable to the grower when the plant begins to wilt, or dies. Although they feed mainly on cabbages and broccoli they will also burrow into root crops such as swedes, turnips and radishes. The losses are considerably higher for these crops as the insects are directly feeding on the edible part of the plant.

For this project the research team is currently growing broccoli on two sites, one in Ireland (North Dublin) and one near Newcastle. They are comparing conventional management of soils (tillage and chemical fertilisers and pesticides) with organic management.
Initial analysis of the Irish site indicates that organic soil management, which involves adding pelleted chicken manure and calcified seaweed increases the number of microscopic fungi and worms (nematodes) which feed on the larvae of cabbage root flies. Suitable natural fertilisers can be found in garden supply shops and websites and ideally should be dug into the soil in autumn or spring before crops are planted.

As well as increasing the volume of ‘good’ bugs in the soil the organic treatment should also improve the structure of the soil which helps root growth and drainage and should result in more vigorous plants better able to fight off attacks.

Although the project will run until 2017 the team hopes to have some interim results later this year.


  Related Links
link Watch Out For Illegal Pesticides
link The UK Pesticide Guide 2014
link The Key to Better Profit Lies in the Soil
link Protecting OSR Yield Potential
link Crop Market Update

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