Spider mites latch onto roses in warm weather

Well, the summer heat finally arrived. The forecast for the next few weeks shows temperatures in the mid to high 80s. If you are participating in my prescribed practice of allowing a summer of rest for your roses, you still have several weeks to take it easy before a mid-season pruning. As a wise man once said, “Predicting things is difficult, especially in the future,” but one can only assume it will look a little like the past, especially with the weather.

So I’ll give it a try: If a mid-season pruning is done after the second or third week of September, you can expect two bloom cycles this year. If you would like roses for a special occasion, count back six to seven weeks from that date; the date you land on will be when you need to have your pruning accomplished. Remember, a mid-season pruning is light, removing the many branches back to the main cane to an outward facing bud (found at the base of a leaf where it joins the cane).

A common problem when hot, dry, dusty conditions prevail is the appearance of spider mites. They are small—adults measuring as small as 1/50th of an inch—so they are often very difficult to detect, but you can recognize the damage they do: brown, stippled and/or yellowed leaves, most often nearer the ground, and water stressed plants are particularly susceptible. Spider mites congregate on the undersides of the leaves where they suck the cell fluids.

If you suspect the presence of spider mites, check the underside of the leaves; they may look slightly webby with many tiny dark dots. Lightly rub the leaves between you fingers—spider mites will feel gritty. If you tap the leaves over a piece of white paper you will see small dots that maybe colorless, cream, red, brown, yellow, or green.

Spider mites have many natural enemies (beneficial insects), so if you apply a broad spectrum pesticide you may actually end up with more spider mites because you killed their predators! Fortunately mites can usually be easily removed with a strong water spray directed upward at the undersides of the leaves. Check the leaves periodically over the next few days.

If the mites have returned, you may want to try a simple homemade insecticidal soap solution: In a spray bottle mix three capfuls of Ivory dish soap, Murphy’s Oil Soap, or Castille soap with one quart of water. When temperatures are relatively cool—such as early morning or early evening—spray the undersides of the leaves with the soap solution. Continue to check each day and reapply as needed.

One Response to "Spider mites latch onto roses in warm weather"

  1. DrTerry   September 13, 2013 at 8:22 am

    I have had trouble with spider mites before and finally found a great solution. It is called Greenbug for Outdoors. It is a safe, effective and totally green product that takes care of what I don’t want but is harmless to humans, animals, the environment and all beneficial creatures. Greenbug has taken care of spider mites, aphids, white fly, and leaf miner yet I still have plenty of butterflies and honey bees. And my birds and my dogs are just fine. I get it online at http://www.greenbugalnatural.com and HIGHLY recommend it!


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