by Linda Posson
Colorado State University Cooperative Extension Master Gardener
Vigilant gardeners delight in discovering the first ladybugs of the season. The brightly colored spotted beetles seem to come from nowhere in search of insect pests preying on emerging flowers and leaves in the garden. Although their favorite dish is aphids, ladybugs feast indiscriminately on many small soft-bodied insects. In less time than it takes for a trip to the garden center to buy insecticide, a few lady beetles and their voracious offspring can wipe out an infestation.
Eighty different species of ladybugs (a.k.a. ladybirds or lady beetles) have been identified in Colorado. The ones you will most likely encounter are the convergent lady beetle, one of several lady beetles of European/Asian origin now present in Colorado and the European species (the archetypal ladybug) with seven spots. Adult ladybugs develop through a pattern of complete metamorphosis involving egg, larval, pupae and adult stages. It's important to recognize the larvae because they are the most prodigious eaters and active hunters. They are elongated bodies, black or striped six-legged grubs and don't look at all like the adult.
Two other common beneficial insects found in the garden are green lacewings and syrphid flies. The adult lacewing is a pale green elongated insect with clear, highly veined gossamer wings. The main function of this pretty but fragile adult is to produce the eggs that develop into vicious brown larvae resembling 1/4 to 3/8-inch Gila monsters. With two hooked jaws as weapons, these tiny eating machines will feast on aphids, caterpillars, mealybugs, and many other species.
Syrphid flies are often mistaken for small bees because they are yellow or orange and black striped and hover over flowers searching for nectar. The larval stage, a tapered maggot, is an aphid gourmand and can consume dozens of them in one day. You may see syrphid flies before your first ladybug because they come into the garden earlier in the spring.
Once you recognize the good bugs in your garden, how do you keep them there? Like all creatures, beneficial insects have basic needs for survival. They require adequate food, safe shelter, and water. Since they are voracious eaters, especially in the larval stages, they need a steady supply of insect prey plus a supplement from pollen and nectar producing flowers. Alyssum and other tiny flowering plants are attractive because they are shallow and produce nectar throughout the summer. Yarrow, fennel, coriander, lavender, dill and fennel are also favorites. The insects will seek shelter in trees, shrubs, grasses, and leafy plants and in mulch around plants. Leaves and grass after irrigation and rain are good sources of water. It is essential to minimize the use of insecticides around beneficial insects. If you must resort to chemical or organic insecticides, apply only those that are compatible with beneficials and be sure not to destroy all the bad bugs. Remember that beneficial insects need a supply of aphids and other soft-bodied pests to be effective predators.
The army of good bugs is the gardener's natural ally in the war against insect pests and can be far more effective than an arsenal of insecticides. To make the most of these valuable garden partners, learn to recognize them in both the adult and larval stages and invite them into your garden by offering an attractive and safe habitat.
For more information see Fact Sheets #5.594
- Lady Beetles and #5.550
- Beneficial Insects and Other Arthropods. You can also call
Planttalk Colorado toll free at (888) 666-3063 and request recording No.
Q: What are the cone-like growths that appear on some spruce trees during mid-summer?
A: Although they look vaguely like cones, the strange growths you notice on the spruce trees are probably Cooley spruce galls produced by aphid like insects called adelgids. The insect requires two hosts (Douglas fir and spruce) to complete its life cycle. During spring when the insect is developing and feeding on the spruce, the galls begin as a slight swelling at the base of needles and are not as noticeable. By mid-July, as the adult insects emerge and migrate to the Douglas fir to complete the life cycle, the galls dry out and start to take on the brownish color of cones. Although the galls affect the look of the tree they do very little harm.
Q: What are Cold Hardiness Zones? Which zone applies to Fort Collins?
A: The USDA Cold Hardiness Zone Map delineates the average minimum low temperature for all regions of the US. Most of Fort Collins falls into zone 5 where the minimum temperature range is from -20 to -10 degrees (Fahrenheit). Although temperature tolerance is only one measure of a plant's hardiness, it does give the gardener a basis for selecting suitable plants for the garden. Nursery stock is tagged with planting instructions, soil, light, and moisture requirements, as well as a range of suitable growing zones. Garden catalogues usually include the range of zones applicable to each plant. Remember that microclimates exist that may have temperatures higher and lower than the average.
For unusual ornamental interest in a narrow spot in the landscape consider planting Karl Foerester feather reed grass. At 3 to 4 four feet tall by 3 feet wide, this upright ornamental grass will add color and interest throughout the year.
A kitchen herb garden can be as close as your back door or patio. Planted in a large (16”) container in a sunny location, a combination of sage, basil, dill, oregano, rosemary and parsley can satisfy the culinary needs of the most dedicated cook.
Large blocks of summer color in the landscape can be provided by several easy-to-grow shrubs which bloom throughout the summer months. Among these are butterfly bush, many of the hardy shrub roses, Russian sage, hydrangea, potentilla and bluemist spirea.
Edging a vegetable garden in marigolds or other bright annual flowers can add color and pizzazz.
If space and/or time for a salad garden is limited, try growing different kinds of lettuce and salad greens in a large hanging basket. Colorful, tasty salads can be easily grown right on the porch or patio.
The authors have received training through Colorado State University Cooperative Extension's Master Gardener program and is a Master Gardener volunteer for Larimer County.
Gardening and Insect Fact Sheets are available on-line by clicking HERE.
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