Establish Natural Defenses
For long-term pest control improve the soil in your yard by adding organic matter to it at every opportunity. It will help keep your plants healthy. Dig in peat moss, compost or other organic matter when you plant new plants. Leave your grass clippings on the lawn to decompose. Best of all, spread a layer of organic mulch over all the bare soil under existing plants. As it slowly decomposes, microorganisms and earthworms incorporate its spongy tissues and valuable nutrients into the soil below, improving soil structure and drainage. Mulches also harbor many beneficial organisms that prey on pests such as scale. Maintain a 2 to 4 inch layer of chopped leaves, grass clippings, compost, hay, shredded paper, or straw on the soil year round.
Create Landscape Diversity
Many organisms parasitize scale by laying their eggs inside their shells. Therefore, another way to combat scale is to encourage the many insects and organisms that normally prey on scale insects by planting lots of different kinds of plants in your yard to make it hospitable to a variety of natural predators. Besides those that reside in healthy soil, there are other natural predator insects that feed on plant nectar and pollen, amphibians and birds. These different kinds of predators will take up residence in a yard that includes their favorite plants for food and shelter. So, the greater the variety of plants on your property, the greater will be the diversity of natural enemies of scale and other pests attracted to it.
Keep Trees, Shrubs and Plants Vigorous
Keeping plants healthy and happy is the best way to prevent problems with pests or disease. Healthy plants are able to summon natural defenses and ward off most attacks. Make every effort to improve the health and vigor of trees, shrubs, vines, groundcovers, flowers and vegetables by watering during dry periods over the summer and fertilizing in the fall, if appropriate. Promptly prune any injured or broken branches or stems cleanly and carefully. Mulch to discourage weeds, keep the soil moist, provide nutrients and sustain beneficial organisms. Feed and water houseplants regularly and make sure that they have sufficient light. Keep them away from drafts and heating vents
Correct Conditions That Encourage Scale
Unless the underlying stress that made your plants vulnerable to scale attack is identified and corrected, the pests may return next year or even later in the season. Give some thought to the affected plant’s situation. Correct conditions of drought, improper light, poor air circulation and over-fertilization. Prune back or remove nearby plants that have grown to block light or rainfall from the plant. Boost the vigor of vulnerable or aged plants with a plant tonic containing enzymes and kelp that is rich in minerals and micronutrients.
Houseplants are under stress simply because they are indoors in artificial conditions. Dry heat, lack of air circulation, drafts, and lack of natural predators virtually guarantee that they will have pest problems. Try to mitigate these conditions by providing humidity, good light and proper moisture. Treat scale and other pest problems promptly when they appear. Repot in sterile soilless potting mix when plants get potbound or their soil gets crusty on top from mineral deposits from fertilizers.
Spray During The Winter
If you have a fruit tree or a shrub that normally loses its leaves in the fall, and some of the leaves don’t drop, suspect scale. If a closer look confirms that scale is present then spray stems and branch surfaces in the winter with heavy horticultural oil, (also called dormant oil or Volck oil) to kill any eggs or emerging nymphs. Any shrubs or trees that suffered scale attack last season are also good candidates for a preventative dormant oil spray during the winter to forestall a reoccurrence next season. Be sure to spray before any leaf or flower buds begin to swell and open. Follow label directions.
Attract Beneficial Insects to the Yard
Like other insect pests on your plants, most scale eggs and insects normally fall victim to natural predators that reside in your yard. If you don't use broad-spectrum insecticides that kill them along with pests, populations of beneficial insects such as ladybugs, green lacewings, braconid or chalcid parasitic wasps patrol your plants in search of scale. To boost their numbers plant lots of different kinds of plants that will provide them a source of nectar and pollen. Sow Border Patrolä, a seed mix of wildflowers particularly attractive to beneficial insects.