For two years, I have had trouble with bush beans and last year there was also trouble with tomatoes. The leaves on the beans turned yellow, then brown and then fell off. The tomato leaves turned brown and fell and there was hardly any fruit. It was either under the tomatoes or the beans that I saw what looked like little red ants. I don’t remember which. Is there anything I can put in the soil to combat this? Do coffee grounds help?
I think it was the squash borer that got into my zucchini.
I do try to rotate my vegetables.
It sounds as though both of your vegetable crops could be suffering from fungal diseases or blights. Bean blight, for example which is caused by a bacterial infection, is transmitted through the soil or by insects. As the bacterial infection takes root, the bush bean plant will show yellow or brown spots on its leaves. Plants that have been drastically infected should be removed to prevent the disease from spreading. Bean blight enjoys moist, warm conditions. To prevent blight, give your plants enough space to allow water to evaporate from the leaves and stems — use drip rather than overhead watering methods if possible. Do not plant your bush beans in areas where blight has occurred in your garden.
Ants would not be the cause of this problem in the beans or tomatoes. However, two insects that can cause yellowing and browned leaves in bush beans are thrips and aphids. Thrips attach themselves to the undersides of leaves, where they suck out the sap, leaving brown specks. Aphids cause the younger leaves they prefer feeding on to turn yellow or turn brown and curl as the aphid infestation progresses. Treat infected bean plants by spraying the plant thoroughly with a ready-to-use insecticidal soap to protect plants and stop the infestation.
Your tomatoes may also have a fungal disease such as tomato blight. Blight starts with the lower leaves getting brown spots, turning yellow and eventually dying. The disease will spread up the plant and eventually defoliate the entire plant. Warm, wet weather can be a factor.
To prevent such fungal diseases in both plants, you should clean up and destroy all diseased foliage in the fall, rotate your crops so that neither beans nor tomatoes are planted in the same spot for at least three years, and mulch new plants to prevent water from splashing the spores from the ground onto the leaves. You can also spray with an organic fungicide such as copper or Bacillus subtilis. Good luck.
You may wish to refer to the following article for additional information : www.omafra.gov.on.ca/english/crops/facts/06-047.htm