Late blight in tomatoes
Is there a spray that can be used to prevent late blight in tomatoes? We lost our entire crop this past year, 2014. In 2013 we had no problems, but lost the crop in 2012. Also are there varieties that are resistant to the blight?
Huntingdon County Pennsylvania
Late blight is a class called a water blight. It acts like a fungus, but is in a different category. Late blight winters over in any plant debris left from last year. It can't (yet) survive in the soil without some part of its host. When late blight occurs, it is important to bag or burn every part of the remaining tomato plants including roots, leaves, stems, and fruit. Penn State publishes a fact sheet that will give you more information.
When you plant tomatoes this year, put the plants in a different part of your garden. Buy plants from known suppliers, not box stores. Locally grown plants are best. Late blight needs wet conditions to survive and spread, so be careful to keep the foliage on your tomatoes dry and mulch under them so no rain water splashes soil up from the ground onto the leaves. Only water at the soil level, not with an overhead system that wets the leaves.