In 2006 we had the longest period of extended summer weather since records began, and gardeners certainly noticed the effects on fruit and vegetable crops. Many were picking runner beans and courgettes right up until the beginning of November and saw yellow daisy-like flowers on their Jerusalem artichokes for the first time. Apples started to bloom again; globe artichokes produced second crop and so did some fig trees.
Usually figs only have a second ripening in sub-tropical areas or in glasshouses, but at Reads Nursery in Norfolk which has the National Collection of figs planted outside, several varieties produced a few late fruit – a phenomenon which staff have never seen before. Even more of a novelty was the banana plant which flowered and fruited outside in the garden of Clare College in Cambridge!
However it wasn’t all good news. The wet and warm weather encouraged fungal diseases such as mildew and rust. It was also heaven for slugs and snails, and allowed certain other pests to continue feeding and multiplying for much longer than usual. Researchers recorded many types of aphid on the wing several weeks later than average, for example, and some commercial growers reported problems with a large autumn generation of cabbage root flies.
So has this warm autumn stored up trouble for next spring? Not necessarily, thank goodness. “To a certain extent most pest life cycles are locked into changes in day length,” says Rosemary Collier, Research Entomologist at HRI Warwick. “So some will have ‘shut-down’ regardless of the warm weather.”
With pests such as cabbage root fly and carrot fly, the extra late generations of maggots don’t necessarily develop enough to form pupae – the stage in their life cycle in which they are able to over-winter. As for aphids, providing we get usual level moderate frosts this winter, the population should be reset at normal levels by spring.
Give us your thoughts on the indian summer. Has it meant an extended growing season, or simply more time for the pests to destroy your crops?
