Back in the 1980’s I was lucky enough to ask a question on radio’s Gardeners’ Question Time. Much to my teenage daughter’s embarrassment, my question was: “I have whitefly on my brassicas, can the panel recommend a remedy?” It turned out that the whitefly were harmless and could be washed off with a hose. There are other insects, however, that present a greater problem to gardeners, as did the cabbage white butterfly during wartime, and still does.
In 1917, a writer to the Sheffield Evening Telegraph was offering cash prizes to children “who send me the largest number of cabbage white butterflies or cabbage caterpillars”. The country was at war and, to justify this massacre, maximum food production was essential, as it was again in 1940 when the Royal Horticultural Society provided advice to vegetable gardeners:
Experts of the Royal Horticultural Society recommend the most effective way to destroy caterpillars of the cabbage white butterfly is to dust the plants with either a non-poisonous derris dust or a poisonous nicotine powder. The former may be applied with impunity to maturing vegetables, the latter only to young plants, but both should be used against the young caterpillars, which are more readily destroyed than the older ones, and before any appreciable amount of damage is done to the crop.
(Boston Guardian, 21 August 1940)
On holiday recently I read a review of a new book Silent Earth: Averting the Insect Apocalypse by Dave Goulson, a Professor of Biology specialising in the ecology and conservation of insects. Some of the statistics in the book are mind-blowing. Apparently, one million types of insect have been named, but specialists like Dave think there are four million more waiting to be identified. We know that insects pollinate, break down waste and provide food for us, but we still continue to massacre them in large numbers. Perhaps, therefore, we should cover our brassicas the best that we can but leave a few plants so that butterflies can continue to secure a place on this earth.
By Paul Freeborough, volunteer
If you would like to learn more about gardening for wildlife and nature conservation, consider volunteering at our Urban Nature garden.