Plant oil controls spider mites

Meyer lemon is often attacked by spider mites indoors. Walter Reeves photo

Meyer lemon is often attacked by spider mites indoors. Walter Reeves photo

Q: On your radio show you mentioned a product that you use to get rid of spider mites on your lemon tree. What is it? Bruce Alberts, Covington

A: Since I eat the Meyer lemons, I use products that are easy to wash off. I tried insecticidal soap first but it seemed to have little effect. I got better results with products that contain plant oils (Natural Guard Neem Spray, Dr. Earth Garden Insect Killer, etc) sprayed along stems and under the leaves. I also closely examined the plant and used an oil-saturated artist's brush to sweep away the webs at the base of leaves.

Q: With such nice weather recently, is it safe to prune Knockout roses? Ivan Cottrell, email

A: It is safe only if you can confidently predict there will be no more cold weather this winter. Otherwise, pruning now may stimulate buds to swell, and these could be damaged in freezing weather later. I recommend pruning in late February when the buds are easy to see and the chance for a deep freeze is remote.

Q: With the recent warm weather, should I put pre-emergent down? Jason Cohen, email

A: I don't recommend it. It's actually soil temperatures that determine when summer annual weed seeds germinate. Soil temperatures won't get high enough to stimulate that until late February at the earliest.

Q: We got a box of delicious Royal Riviera pears from Harry & David Gifts. If we plant the seeds will they grow the same pears? Rick Parks, Madison

A: It's not likely you'll have success. In the first place, because you don't know exactly where the pollen came from that produced the seeds, the resulting tree might not yield anything that looks like the fruit you received. Royal Riviera is simply a trademarked name of a type of Comice pear grown in Oregon. Like Bartlett pear, this fruit does not do well at all in Georgia. Fire blight bacterial disease usually wipes out these trees after just a few years.

Q: What can I spray for bugs on my roses instead of systemic insecticides that kill honeybees? Anis Shaw, Gainesville

A: It's true that systemic insecticides can harm bees, but despite the brouhaha over their use, insecticides are not the only cause of Colony Collapse Disorder (CCD). Mites, poor management, less diverse bee genetics, and exposure to pesticides other than systemic insecticides each play a major role. If you want to use fewer chemicals on your roses, consider bio-rational insecticides like neem oil and give them a forceful water spray each week. More details on CCD at bit.ly/GAbeedeath.

Q: What are the best greens to plant for the winter? Gilbert Williams, Newton County

A: Collards, turnip greens, lettuce, and spinach are easy to plant from seed in September. Given water as needed, they will give you much to harvest through most of January. I have a host of good vegetable gardening links, including a suggested small garden plan at bit.ly/UGAgardening.