成人快手

An organic way to treat white flies on French beans

Post categories: french bean,听pests,听question

Sally Smith | 11:02 UK time, Friday, 13 August 2010

Organic gardener Sally Smith answers your questions about white flies on French beans. If you have a similar problem with your French beans,听share your experiences in the comment section below.

Lesley Hardy from Kings Lynn asks: I have lots of little white flies on my French beans. Are they anything to do with white butterflies as there seem to be lots about? I am spraying them with washing-up liquid. Is that OK as I don't like using chemicals?

Answer: The flies are not related to white butterflies, these are cabbage white butterflies and are a specific pest of plants in the cabbage family, they will not therefore harm your beans. I wonder too if the flies that you see are actually damaging the bean plants or whether you are spraying unnecessarily? The first 'rule' of treating a problem is to first identify it accurately otherwise we are in danger of killing creatures needlessly that are doing no harm and may indeed be beneficial creatures that are predators of pest species!

That said, there is a pest actually called 'whitefly', it is a tiny white fly, 2mm to 3mm long, usually clouds of them fly up when plants are disturbed though they mostly infest cabbages and not beans.

My advice would be first of all to stop spraying altogether and definitely do not use washing up liquid as it is not suitable to be used on plants and is not particularly effective at clearing up pest problems. Observe the plants regularly for actual damage - such as leaves turning yellow, developing black mould on the upper surfaces (sooty mould) and seeing flies and their young (they look like tiny scales) feeding on the undersides of the leaves. If these symptoms are present, treat as for whitefly with an insecticidal soap spray based on fatty acids. Spray in the evening to avoid beneficial insects such as bees and target the undersides of the leaves where the flies are found, always follow the manufacturers instructions for spraying.

Bookmark with:
|
|
|
|
- What's this?

Comments

About this blog

The Dig In campaign has finished now. Thanks to everyone who took part in the campaign throughout 2009 and 2010. We hope you enjoyed growing the Dig In seeds, especially those of you who are new to growing vegetables. This site is no longer being updated, but it is still packed full of useful information about growing veg.

Subscribe to Dig In Blog

You can stay up to date with Dig In Blog via these feeds.

Dig In Blog Feed(RSS)

Dig In Blog Feed(ATOM)

If you aren't sure what RSS is you'll find useful.

Expert authors

Our video expert is Blue Peter gardener Chris Collins. He's a qualified horticulturalist and award-winning gardener, who's presented shows on everything from allotments to Chelsea - . He loves sharing his experience with growers old and new!

Gareth Austin is resident gardening expert with 成人快手 Radio Foyle and lectures in horticulture in Northern Ireland. Gareth has made it a prority to encourage gardeners throughout Northern Ireland to 'reclaim the space' and start growing vegetables in any area they can find.

Maria del Carmen Casarrubios is a tutor and practical instructor at , Regent's Park. She trained at Capel Manor and Writtle College in Amenity Horticulture and has 20 years' experience of working with plants. Sally Smith

Sally Smith is a freelance gardening researcher and lecturer. She headed the advisory team at Garden Organic for many years. Pest and disease control by organic means is her speciality, Sally says: "Managing your soil is key to solving nearly all gardening problems, look after your compost heap, it's your most important asset." Sally Smith

Brendan Little trained at and . Brendan runs organic gardening courses, works as a garden designer and is in the 成人快手 Radio Ulster Gardeners' Corner team." Sally Smith

Karen Kenny is the Eastern Region Rep for the National Society of Allotment & Leisure Gardeners as well as on the management team of Suffolk and Ipswich allotments where she runs a site. Karen is also an accomplished lecturer on most gardening subjects, including allotments.

Peter Horrocks has an allotment in Newcastle. He's the regional rep for the in the North of England & Scotland, the secretary of the Newcastle Allotments Working Group. Plus, Peter is secretary of a ten-acre allotments site in Newcastle, considered by many to be one of the best in the city.

Ben Raskin is an advisor with the , as well as helping to run 22 acres of organic vegetables. With over 16 years of horticultural experience, including running market gardens and working at the Welsh College of Horticulture, he's an expert on organic matters.

Beechgrove Potting Shed is Radio Scotland's top gardening show, giving tips and advice to Scottish gardeners - and the odd Dig In grower - every Sunday.

Zoe tends the Dig In website. When she's not in the office you'll find her gardening on Hampstead Heath and in Regents Park.

Ann "Dig In" Kelly looked after the blog from day to day until May 2010. Bitten by the gardening bug a few years ago, she has progressed from a few growbags to a great big polytunnel. She hates slugs.