Wednesday, April 17, 2013

Beware: Tiny invaders munch vegetables

When tiny snails showed up on my garden vegetables last summer, it puzzled me. These were totally unfamiliar and certainly unexpected. My thoughts immediately turned to zebra mussels, those exotic mussels that found their way into the Great Lakes and now pose a menace to native flora and fauna. Was there a parallel with these snails?

On the other hand, I was sure that the snails were just a bumper crop of some native species. Reason dictated that the snails were responding to an early spring and also to frequent rainfall of the summer. But in this case, it looks as though reason was wrong.

The tiny (100 could fit in a teaspoon, with room to spare) snails proliferated and in the case of my garden, succeeded in destroying pounds of chard, lettuce and broccoli. They even defoliated my carrots, although they appeared to dislike parsnip tops. This was a true plague.

All the same, I thought that the snail invasion was probably confined to the Mid-Coast area. Wrong again. According to University of Maine Cooperative Extension, these pesky snails showed up all over Maine. And worse, no one can determine exactly what species of snail they are. The snail boffins are totally perplexed.

Everyone pretty much agrees that the snails are a species of ambersnail, but exactly which species remains a mystery. Some suggest that the snails may be an exotic species, introduced by some unknown means. If that’s the case, then a recurrence of last summer’s snail eruption seems likely. Even worse, no one as of yet has figured out a practical means of controlling the snails.

Our great hope lies in the lingering snowpack of early spring and also, the lengthy time last winter when we had continual sub-freezing temperatures, but no snow cover. This allowed frost to penetrate deeper than usual.

Anyway, since snails (perhaps not all snails, I’m no snail expert) spend winters hibernating in underground burrows, deep-penetrating frost last winter may have killed them. If not, we may be in for a rough ride this summer. 

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