Last year I had maggots in my radishes, worms in my broccoli and aphids and black spot on my roses. Is there a way to prevent these and other pest problems?
There are ways to prevent many insect problems. Insect damage on many vegetables can be prevented by covering plants with floating insect barrier fabric. This fabric is made of spun plastic which allows light and moisture penetration but prevents egg-laying adult insects from reaching plants. Soil is placed around the edges to hold it in place.
Maggots are larvae of a fly that lays eggs at the base of susceptible plants such as radish, turnip, beet and cabbage family vegetables. The eggs hatch and bore into the roots. Cabbage and broccoli worms are the larvae of a small moth that lays its eggs on the leaves and flower buds.
Maggots can also be prevented by placing organic diatomaceous earth or a granular insecticide containing Sevin on the soil when planting seeds or plants. Cabbage family plants can be sprayed with an organic insecticide containing Bacillus thuringensis. Common brand names are Thuricide and DiPel. Spray when moths first visit the plants.
When you notice aphids and other leaf-damaging insects, look for bright red ladybugs (ladybird beetles). They will often eat all the aphids before they can do much plant damage. Neem oil is another organic pesticide that controls most leaf-feeding insects. Neem oil also prevents black spot if applied biweekly.
Slugs and snails eat holes in all kinds of plants. They can do considerable damage to newly planted vegetables and flowers. They also damage perennial flowers, especially hosta plants. Sluggo and similar slug baits which contain iron phosphate are safe for use around pets and children. Slug and snail baits containing metaldehyde are also effective.
Lace bugs cause leaf yellowing and mottling on azaleas and rhododendrons. New growth can be protected by spraying now with organic spinosad. Two applications about two weeks apart are needed.
Weed seeds need light to germinate. A 2-inch layer of bark dust mulch will prevent about 90 percent of new weed growth. I remove almost all my weeds by pulling, digging or cultivating. When using a bark mulch, I have found that if I spend five to 10 minutes a day weeding I have completed all my weeding for the week. Even lawn weeds can be removed a few at a time with a forked weeding tool (dandelion digger). Regular lawn fertilization will cause grass to grow thicker, leaving very little room for weeds. Weed and feed will kill existing broad-leaf lawn weeds at the same time the grass is fertilized.