Stop pests dining in your garden
If you have fruit trees or shrubs such as hollies and euonymus, chances are good that they are infested with scale insects, which suck juices from the plants they infest.
A heavy infestation of scale on your peach or satsuma trees can mean a reduced crop and a weakened plant. The latter translates to reduced drought tolerance and more susceptibility to plant diseases and other insects. To keep plants strong and productive, it is important to control scale insects.
One of the distinctive characteristics of scale is that the insects exist under a protective calcium coating. That means that a normal spray of insecticide such as malathion or spinosad that would control aphids and other sucking insects does not work.
Control scale by applying dormant or horticultural oil, which coats the calcium cover and eventually suffocates the scale insect within its shell.
Now is the time to apply these oils. Watch for a two-day period where the temperatures are forecast to stay above 45 degrees. Any colder and the spray will not work.
The stems and trunks with scale obviously need a generous spray, but also apply it on any leaves and leaf stems that have scale. The response will not be immediate, but within a few weeks, you should find that the scale will be relatively easy to scrape off with your fingernail.
That indicates that much of the scale has been killed.
Do not wait too long into the season to spray dormant oil, as it can injure some annual flowers, fruit blooms and new foliage. Spray before those come in. For more information, closely review the label.
If you planted spinach transplants earlier in December, you are probably experiencing an infestation by cucumber beetles. They resemble ladybugs except they are light green with black spots. They eat holes in spinach, turnip and chard foliage.
If the damage is severe to those greens, they can be sprayed with malathion. Spinosad or one of the other organic insecticides also may provide some control.
If the damage is not severe and you can tolerate it, avoid an insecticide and go ahead and eat the greens with the holes. Doing without the insecticide will mean that the ladybugs sharing the greens with the beetles will also survive.
Cabbage loopers feed in a linear path from the edge of the leaf toward its rib, and you can see the damage on broccoli, cauliflower and collards. Use a Bt product such as Thuricide, Bi-Worm Killer or Dipel to control them. The product is derived from a bacterium, and it quickly ends feeding and causes a terminal constipation in the caterpillars.
Caterpillars are the only organism that it affects, and only those that consume the sprayed foliage. A single spray is only toxic (effective) for five to seven days.
A Bt application seems to be most effective if the container has only been open for two years or less and if you add a teaspoon of dish detergent such as Dawn to each gallon of solution.
The cold weather seems to have reduced slug and snail activity except on primula, pansies, cyclamen and lettuce. The easiest way to protect these low-growing snail favorites is to apply a slug and snail bait every two weeks. Both chemical and organic baits work well. Follow label instructions.
Beer traps are another effective slug and snail treatment. Sink a sturdy plastic cup into the soil so its top is level with the surface and fill it halfway to the top with beer. The slugs and snails will make a suicidal leap into the beer.
Slugs and snails are not fussy, so the beer can be inexpensive, warm or even stale and it will work.