Last year, I lost most of my tomatoes to blight. Is there anything I can do to the soil to kill the blight in the soil? And what about those cucumber beetles that kill healthy plants?


Q: Last year, I lost most of my tomatoes to blight. Is there anything I can do to the soil to kill the blight in the soil? Would a plastic or cloth mulch over the ground to build up heat help?



A. The simple answer is sanitation. Unfortunately, with warmer global temperatures, blight is here to stay; all we can do is try to minimize the damage. Composting all die-back and debris in the fall and cleaning up winter kill in the spring removes host sites for insects and diseases.



Blight is a mold, and molds right now are sporing like crazy. Mix up some dish detergent and bleach in a hose end sprayer (one-third cup of each per gallon of water) and spray the vegetable garden and the planting beds around the garden (avoid plants that have already come up). Turn the vegetable beds and spray them again. That should kill a lot of the mold and insect larva.



A barrier between the plants and the soil is a good idea, but I would use newspaper instead of plastic. The bad guys like heat, and I think the plastic mulch will promote their preferred environment. Paper will keep the soil cool. Also, space the plants at the proper distance to promote good air circulation.



Every two weeks during the growing season, mix dish detergent and ammonia in the hose end sprayer (same ratio) and wash all of the plants in the entire yard. If you use liquid fertilizer, you can add it to the mix.


Q: I get cucumber beetles. Once they arrive, my healthy plants quickly die from wilt. I have noticed that later in the season, they are not present. Should I just plant the cucumbers much later in the season?



A: You are right about the cucumber beetles. They provide a double whammy; opening wounds when they suck the juices out of the leaves, creating access for the wilt virus that they incubate in their tiny little bodies.



They sit on the garden fence waiting for you to finish, and then lay their eggs at the base of the plants. Since they only go through one life cycle per growing season and are plant specific, you could skip growing cucumbers for a couple of years to draw down the population or wait until mid-July to bed your plants.



If you do decide to grow cucumbers, here I would lay down black plastic mulch. The beetle’s body has yellow-green and black stripes; when you come out to check the plants, they fall to the ground hoping to blend in with the background. Unfortunately for them, yellow bodies stick out on a black background. You can pick them up and drown them in a coffee can.


Have a gardening question? Send it to mastergardener@rcn.com. Peter Coppola is a principle master gardener. A lifetime gardener and gardening advocate, he teaches and lectures on the subject in the Burlington, Mass., area.