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Amending the soil improves the environment for good root growth and the development of soil microorganisms. Mulch reduces surface evaporation, controls soil temperature fluctuations, and discourages weeds. Mow grass at a height of 2 to 3 inches, and leave the clippings to encourage beneficial microorganisms and earthworms, which will digest thatch and maintain healthy soil. Nitrogen and other nutrients then recycle into the lawn and promote steady grass growth, which minimizes mowing and fertilizing. The use of soaps and detergents, as well as spray oils, target specific pests without being detrimental to beneficial insects.
Most insects and other arthropods do not feed on or harm plants; they are just passing through. Others feed on and destroy pest species. Beneficial arthropods generally are either insect predators or parasites. Predators include lady beetles, lacewings and spiders. Common insect parasites are tachinid flies and the braconid and ichneumonid wasps.
Predators
Lady beetles: adults and larvae feed on large numbers of small soft-bodied insects like aphids. One group is important in controlling spider mites.
Green lacewings: adults primarily feed on nectar and other fluids. The larvae are voracious predators, feeding on small caterpillars, beetles, aphids and other insects.
Syrphid flies: larvae feed on dozens of small, soft-bodied insects, especially aphids early in the season when cooler temperatures may inhibit other predators. A small, bright orange predatory midge often can be seen feeding on aphids late in the season.
Predatory bugs: several species feed by piercing the prey and sucking out body fluids. These include red and black species of stinkbug, light brown damsel bugs, small pirate bugs, ambush bugs and assassin bugs.
Ground beetles: various species will feed on almost any garden pest that spends time on the soil surface.
Hunting wasps: a large number from several insect families prey on pests and are very important in controlling them. For example, the common Polistes paper wasp thoroughly searches plants, often providing substantial control.
Predatory mites: several species feed on spider mites, and provide good control except during low humidity conditions. They are also more susceptible to insecticides than plant-feeding species.
Spiders: all spiders feed on insects or other small arthropods. Some spiders make webs, but others do not and move about, hunting for their prey on soil or plants.
Insect Parasites
Tachinid flies: adults lay eggs on pests, usually near the head. The eggs hatch almost immediately and the maggots tunnel into the host. They feed internally, killing the host.
Braconid and ichneumonid wasps: of this large and diverse group some attack small insects, others live in eggs of pests, and others attack larger insects.
Although some predators and parasites are available commercially, artificial releases haven't clearly demonstrated an effect on pest insect populations.
For further information, see Fact Sheet #5.550 - Beneficial insects and other arthropods in the yard and garden; 7.222 - Soil - the key to successful gardening; 7.214 - Mulches for home grounds; 7.007 - Eliminate grass clipping collection; 7.202 - Lawn care; 7.217 - Fertilizing the organic garden; 5.547 - Use of soaps and detergents for insect control in Colorado; and 5.569 - Spray oils for insect and mite control on woody plants. You may also call PlantTalk Colorado toll-free at 1-888-666-3063 and request message 1421 on beneficial insects.
Q: Whenever anyone walks on my front lawn there are footprint indentations that don't go away; do I need to de-thatch my lawn?
A: This could be an indication that your lawn needs water. One symptom of drought stress is called "footprinting," that doesn't go away within an hour. Actual wilt will soon follow and the turf will take on a gray or purple/blue cast. A few areas can be spot-watered to avoid too much water on the rest of the lawn. The important thing is to water appropriately for a healthy lawn: less frequently and more deeply. Water in late evening or early morning. For further information refer to Fact Sheet 7.202 - Lawn care.
Q: Can I use the sawdust from our workshop for mulch?
A: Sawdust is generally ok to use, but a couple things must be kept in mind. Fine sawdust may crust, and some sources such as walnut produce toxic substances. The addition of nitrogen usually is necessary. During decomposition some of the soil nitrogen in contact with the mulch is used by the breakdown organisms. A sign of nitrogen deficiency is a yellowing of primarily the lower leaves of plants.
Do not throw perennial bindweed (field morning glory) plants into the compost after pulling them. The roots and stems easily withstand the composting process and will form new plants upon being combined with soil.
Try not to step into flower or vegetable beds when weeding, cultivating, picking or spraying. The clay soils of Colorado's Front Range compact easily depriving plant roots of needed oxygen. Compaction may kill plants or at least diminish their performance.
Irregular patches of straw-colored or yellow turf in an otherwise green lawn often are signs of leaf spot/ melting out disease. Small, elliptical dark brown spots are found on infected leaves. Fungicides are usually not needed. But sound management practices can help. These include core aeration, watering deeply and less frequently and avoiding overuse of high nitrogen fertilizer.
Be vigilant in keeping trees free of suckers and water sprouts. Water sprouts appear as small branches on the trunks and suckers grow up from the roots. These new growths are prone to disease and use the tree's energy needlessly.
The author has received training through Colorado State University Cooperative Extension's Master Gardener program and is a Master Gardener volunteer for Larimer County.
Fact Sheets are available at the Larimer County Extension Office, 1525 Blue Spruce Drive, Fort Collins, Colorado, telephone (970) 498-6000, or contact us by e-mail at larimer@coop.ext.colostate.edu
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