|
QUESTION Over the past three years, we've seen an increase in grasshoppers at our Georgian Bay cottage, and last summer we were overrun with them. Why am I seeing so many and what can I do to keep them from eating the flowers and vegetables in my garden? Kay Gillespie, Pointe au Baril, Ont.
ANSWER The grasshopper specimen you sent us to help answer your questions got damaged in transit, and arrived in Cottage Life's offices squashed and missing its head. We didn't think even an entomologist would be able to identify it - but we were wrong. From a series of e-mailed photos, grasshopper expert Dan Johnson at the University of Lethbridge pegged it as a male specimen of the lesser migratory grasshopper, Melanoplus sanguinipes. It's an extraordinarily successful species, widely distributed across Canada and as far south as Florida - and though most commonly found on grassland, it also (as you've discovered) eats broadleaf plants. Grasshoppers of many species have recently increased across the country, including in Ontario, Johnson says. That's probably due to several years of warm, dry conditions, which give them more time to complete their growth cycle and mate, and also allow more young to survive. Typically, the effect of such a population surge continues for a year or two beyond the conditions that caused it, so even though the summer of 2003 was a fairly cool and wet one, you're still seeing the results of the warm-weather increase. There are no chemical pesticides Johnson would recommend to control grasshoppers around the cottage. However, since cool, moist conditions slow them down, and also encourage the growth of fungi (which cause disease in grasshoppers), it may help to keep your plant beds moist and your most vulnerable plants well irrigated. To protect small areas, you could try sticky paper or screening. For veggies, floating row covers - held down by soil and rocks - let in light and moisture and allow for growth, while keeping hopping and flying insects out. Over a larger area, there's not much to be done, says Johnson, beyond waiting for the population to recede - as it will, given the cyclical nature of grasshopper infestations. Jo Currie
* Published in the April/May 2004 issue of Cottage Life |