Saturday, June 21, 2014

Leafminer Lament

Every spring I plant cool-season lettuce along with the other must haves - Swiss chard, spinach, arugula and beets.  It's been a good season for leafy crops, despite the hail.  We've had seven hail events at our house, luckily they didn't do too much damage.  The raised bed tunnels and shade cloth provide excellent protection from the hail and heavy rains.

Our nephew Max with Ferris after the 7th hail storm this season
Each year the dreaded spinach leafminer (Pegomyia hyoscyami) finds us or at least our plants.  They don't have to go far, the pupal stage overwinters in the soil, then emerge in the spring as adult flies only to lay their eggs on host plant leaves to start the cycle again.  The larvae tunnel between leaf layers of Swiss chard, spinach, beets, potatoes and peas.  In our raised beds they really favor Swiss chard and beet leaves. Their tunneling trails are easy to detect and if left to their own devices, they will destroy many leaves on the plant. Control is difficult since they are in the actual plant tissue.  About all I'm doing now is pinching off affected leaves and throwing them away.  Any leaves left around will only keep their life cycle going, so don't let any leaves remain near the plants after removal.  There are still plenty of unaffected leaves and we're harvesting them quickly, better for us to eat them then the miners!

Going forward I'll rotate crops and keep susceptible plants covered with light weight floating row cover to keep the flies from laying eggs. 

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