|We have rose bushes, plantains and other plants that seem to get small holes in the leaves very year. What could be the cause and a cure?|
|That's hard to say. There are numerous insects that could leave small holes and without knowing what they are, it's difficult to recommend a management option. I suggest that you examine the plants carefully and often. Perhaps use a small magnifying glass and look under the leaves as well as on top. Examine during the night for nighttime eaters.
Healthy plants can withstand some insect damage and keeping plants appropriate watered and fertilized is the best thing you can do to provent insect problems. For pest control, I always start with the simplest method first, and if that isn't successful, move on from there. A strong blast of water from the hose works on numerous insects. Spray underneath leaves, in between, etc. Do this daily.
If that doesn't work, try a soapy water spray. Use 1 teaspoon to 2 tablespoons of liquid detergent soap per gallon of water. Use regular, not concentrated soap. Don't use soaps with lemon, as the citric acid can burn plants. Start with the lower amount and work up as needed. Spray as often as needed. As with any spray you might wish to test it on a few leaves first before you treat all your plants. Next on my list would be an insecticidal soap spray.
The insecticidal soaps are made from plant-derived fatty acids and target soft-bodied insects. There's really no way you can target the bad guys without fallout on the good guys. If you can regularly monitor and tolerate some damage to your plants, over time Mother Nature strikes a balance, with the beneficial insects coming in to control the bad guys. I hope this info helps.