September 6, 2005 > Pesky Insects
by Pat Kite
With spider mites sucking the life chlorophyll out of my fuchsias, and my daughter complaining of whitefly attack, I must digress today from my usual ode to flowers.
SPIDER MITES: Spider mites are not spiders. So, for those of you with spider phobia, on that score you can relax. But that doesn't mean these teeny-tiny critters, merely spider relatives, are fun to have around.
Let's start with identification. You may see plant leaves developing a speckled appearance. Ignore this, and the leaves begin yellowing, or turning brown. Poke your spectacles up a bit closer, trying to find out the problem and you may see a few teensy webs around a few leaves. Then, again, you may not.
For those of you with a magnifying glass handy, you can look at the leaves. You will see extremely tiny black dots, the size of this sentence dot. It looks like someone has spilled pepper on the leaves. That is your spider mite infestation, each spider mite being 1/60 inch wide. And there are oodles of them.
What are they doing? Spider mites feed with two needle-like sucking stylets, basically sharp pointed sucking straw-like gizmos. Their food? Plant water and food-producing green chlorophyll. Chlorophyll helps plants digest their food. As spider mites remove green chlorophyll, you see leaf yellowing, first in spotted areas, then the entire leaf. When the plant doesn't get sufficient nutrients, or food, it is going look yucky, and perhaps eventually die.
What to do? Well, keeping plants well watered and given regular fertilizer, helps deter spider mites, especially in hot weather. Spider mites lust after water-stressed plants. You can spray the plant with a contact spray. This kills whatever it contacts. It doesn't kill what it doesn't contact, and spider mites hiding in nooks and crannies multiply rapidly. Or, in desperation, you can use a systemic insecticide. This is a spray that is absorbed through the leaves, quickly filtering through the plant. When a spider mite, or other sucking insect, feeds on the plant, it takes in the
systemic insecticide along with the chlorophyll, and dies.
You must read the container label at least twice for critters controlled by that concoction, and exactly how to apply. For those of you who hate plant poisons, water well, fertilize, hope for the best, and with cool weather, the mite population often goes away.
If clouds of tiny white moth-like insects start flying around when you touch a plant, you have whiteflies. When you depart, they settle back down again on leaf undersides. Whiteflies feed through their straw-like beaks, sucking sap, or life juices, out of the plant [see mites above]. The plant tends to look sickly, but usually doesn't die. However whiteflies excrete, or poop out a sticky liquid called honeydew. Black mold may grow on the honeydew areas. Just so you know.
What do to? You can spray with an insecticide, but unless you have a tremendous infestation, it usually isn't necessary. I have purchased yellow sticky traps for aid with whiteflies on my roses, and this helps. Whiteflies are attracted to yellow, and they stick to the yellow trap tapes. All this paraphernalia is available at local garden stores. Again, and again, read the large and small print of container instructions.
I hope this information helps. Enjoy autumn, my favorite season. Best, Pat