Question: Why are some of the leaves on my plants turning yellow? What is the best all-purpose insecticide to use on my plants which are all in pots and located on my deck? I only have ornamental plants.
Answer: Many perennial and woody ornamental plants lose their leaves this time of year. Yellowing is one of the first indications that they're beginning to rest for the winter, so your plants may not be diseased or insect infested, but just showing signs that autumn weather has arrived. Most insecticides are fairly pest-specific, and no one spray will eliminate all insects. If you find a pest, you can treat the problem by handpicking, or hosing them off with a strong stream of water. If you can identify the pest, you can treat it with something more specific. But use chemicals with care; they can damage some plants. A general rule of thumb is to identify the insect and the host plant, then make sure both are listed on the label of the insecticide you plan to use.
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