Not all insects in our yards are harmful. Don't jump to the hasty conclusion that an insect is a pest unless you have positively identified it, or have seen it actually eating the plant. Many insects are neutral; they do not harm plants. Some insects are beneficial; they prey on the harmful insects that do damage our plants.

 

The descriptions of some common pests are described on pages in our Gardening Guide which will help to identify harmful insects. If you are unsure, the knowledgeable staff at Golden Acres may be able to offer assistance.

 

Listed below are the more common beneficial insects in our area.

 

Centipedes:

This fast-moving arthropod is another of the important ground-dwelling predators. Centipedes are totally carnivorous and never damage plants. Their close relatives millipedes may do damage to soft-stemmed plants but these mainly feed on decaying plant and animal matter. The easiest way to tell these two creatures apart is the number of legs and how fast they move. A centipede has fewer legs and moves much faster than a millipede. Centipedes will eat nearly anything living they encounter including slugs and other centipedes.

 

Ground Beetles:

Ground beetles or Carabids are a very common predator of crawling pests like slugs, cutworms, ants, aphids, etc. Most species are black but some have bright metallic green or reddish shells. The larval form also feeds on pests but they are not as mobile as the adults. As a result, they spend most of this stage of their life in the soil or grass and are rarely ever seen.

 

Honeybees & Other Pollinators:

Although they do not destroy pests, honey bees are considered beneficial because they pollinate plants. Leafcutter bees, bumblebees, carpenter bees, butterflies, and moths also visit flowers to feed on nectar and pollen. These insects and other pollinators are vital for a plant species to survive. Without them many plants would be unable to produce fruit or seeds.

 

Hover/Syrphid Flies:

In both larval and adult form this insect is extremely beneficial though for different reasons. The larva is an important aphid predator. It is hard to identify because it is similar in appearance to a caterpillar differing only by a narrow, eye-less head and faintly translucent skin.. As well, these insects, unlike caterpillars, will be found amongst aphid colonies. The adult form mimics bee and wasp coloring for protection but, as it is a true fly, is unable to sting. These flies merely feed off nectar, pollinating flowers in the process.

 

Hypoaspis Mites:

Sold in the form HYPE-O, these beneficial mites feed on fungus gnats, thrips, bulb mites, weevil eggs and spring tails. They live in the soil as long as they have a food source and up to 30 days without food. However if plants continue to be overwatered they will drown.

 

Lacewings:

Adult lacewings are one of our most beautiful and beneficial insects. They can reach lengths up to 3/4" long, & have long green or occasionally brown lacy wings. The larval form is very similar to ladybug larvae. Both adults and larvae feed on aphids, various insect eggs, mealy bugs and scale.

 

Ladybugs:

Both the larval and adult stages eat insect eggs and soft bodied insects, particularly aphids. We are all familiar with the black-spotted red ladybug beetle, but should learn to recognize the ladybug larvae, which eats more pests than the adults. They are shaped like tiny alligators; the most common types are dark blue with orange or yellow spots.

 

Predator Nematodes:

Predator nematodes eat insects such as grubs, cut worms, and larvae of the carrot rust fly, onion maggot and the crane fly (leather jacker). Nematodes only need to be applied once per season and require a soil tempurature of 10 degrees C. They will not overwinter.

 

Spiders & Harvestmen:

Spiders are voracious predators, feeding on many species of insects including aphids, flies, leafhoppers, mosquitoes and other pest insects. They do not damage our plants or crops and should therefore be left in peace. In fact, these arthropods should be actively encouraged to live in your garden as they do nothing but good.

 

The daddy longlegs or 'harvestman' (not actually a true spider, though often mistaken for one) performs a similar role as spiders. Its main prey consists of ground and plant pests like aphids and small slugs.

 

Others:

Many other insects commonly found in Alberta are beneficial as pollinators, predators, or parasites. Butterflies and moths are, of course, pollinators but so are many species of flies, small beetles, and wasps. Other predators include robber flies, aphid midge larvae (tiny bright orange caterpillar-like animals), predatory true bugs like assassin or ambush bugs, and wasps (including yellowjackets which are excellent preators) and even some mites and thrips. Parasites include many species of wasps which lay their eggs either on or in the pest insect, and some species of mites.

 

 

 

 

Evergreen Insects

 

Spruce Sawfly Larvae are small green orange-headed caterpillars that feed on young spruce or larch needles. They are similar in color and size as a spruce needle and as a result are difficult to see. Ends of branches with new needles missing indicates insects are present. Check your spruce trees regularly from June to July. Spruce sawfly larvae are best controlled with a contact insecticide such as Ambush. Spray infested spruce trees when the caterpillars first appear and, if necessary, again in 10-14 days or after a rain if more larvae are present.

 

Cooley Spruce Gall Aphids are little white fluffy aphids that lay eggs in the new growth of young spruce trees. The larva forms a green gall, a swelling on the end of the branch, which later turns purple and finally brown after the eggs have hatched. Brown galls no longer contain the insect that created them months earlier; they can be removed if you find them disfiguring. Once the gall has formed spraying is useless. If you can, pick the green galls off to reduce the number of aphids that hatch. Insecticidal spraying is generally not recommended for control of this insect.

White Pine Weevil

 

On Spruce: Large white larvae inside the leaders of spruce and pine trees eat the soft tissue. They cause leaders to curl over and the needles on the leader to die in the late summer. In the fall, on damaged trees, you will be able to see telltale holes in the leader where adult weevils have emerged. Once a leader has curled over no control is possible. Cut the leader off just above the next set of healthy branches. To form a new leader, tie a sturdy stick, that extends beyond the cut, to the trunk of the tree. Bend one of the top healthy branches up to it and tie it to the stick. If other healthy branches try to compete, they should be removed. After one year previously damaged trees will have new leaders. Insecticidal spraying is generally not recommended for control of this insect.

 

Pine Needle Scales are small white oblong-shaped crusts on pine needles. These scales can be scraped off with a fingernail. Insects under these scales suck sap from needles and eventually give pine trees a pale sickly appearance. Most insecticides won’t penetrate scale, however horticultural oil may help. Various types of scale attack spruce and juniper as well as pine.

 

Spruce Budworms are seen occasionally but are less common than sawfly larvae in western Canada. The green budworm larvae are larger than spruce sawfly larvae. Budworm larvae also attack new spruce needles, but rather than leaving the ends of the branches bare, they form clusters of silk webbing, bud scales, and debris around the end of the branch. Ambush is an effective budworm control if sprayed when larvae are present.

 

 

Lawn Pests

 

Read the label directions to find out which chemical will work best against the particular insect you are dealing with. Some of the most common lawn insects are listed below:

 

Dew Worms create small mounds in your lawn, making it uneven. Some dew worms are beneficial as they prevent the ground from compacting. If you are overrun with them, apply carbolic soap at the recommended rate (mixing it with water), using a watering can to prevent chemical drift. Water your lawn and surrounding area thoroughly for 1-2 hours in the early evening, then apply the chemical. Remember to read the directions first before you apply the carbolic soap. Remove any dead worms seen, as they are poisonous to birds. Repeat this treatment several times at 2 week intervals and have your neighbors treat their lawns as well to lessen the chance of recurrence. This is only a temporary solution; the best method is to live with them and use gypsum to break down clumps and mounds left by dew worms.

 

Sod Webworms are gray caterpillars that attack the root system of lawns. Circular areas of lawn will die. If the dead grass areas are pulled on the grass comes out of the soil easily since the roots have been damaged. A fine white web can be seen just below ground level. Diazinon is an effective control for sod webworm. Always read and follow instructions on the container label.