Most Common Garden Pests and Solutions
Gardening wouldn't be gardening if we didn't run into pests and problems. In general, we encourage eco-friendly options, planting the right plant in the right place and the use of beneficial predator insects. Learn to identify them, they are the good guys; plant a variety of plants that beneficials like; when a pest problem occurs look for beneficial to see if there are enough of them to control the problem; if you are short of beneficial consider purchasing some to build up their numbers in your garden. Take care of your plants. Ensure that your plants have enough water and nutrients, healthy plants are less likely to have pest problems. If applications of controls are required, use organic and/or least toxic products targeting the problem pests, but not the beneficials. These are the top 10 pests we the Art’s Nursery staff get questions about:
Aphids attack a very wide range of plants, often causing leaves to curl into this. Look for small, soft-bodied, six leg and, sap sucking insects that vary in colour from pinkish – white to green and black. These insects are usually in clusters or colonies on upper parts of stems and the underside of leaves. When these colonies become large, the next generation of aphids will have wings to fly off and start new colonies elsewhere. Secretions of sticky ‘honeydew’ often appear on the lower leaves. This ‘honeydew’ is excess sap that aphids suck from the plant and pass through their bodies.
Did you know? Ants are often found with aphids, they ‘farm’ the aphids for the sugary ‘honeydew’ to feed to their young. Ants will often stand guard over colonies of aphids fighting off predators such as ladybugs and lacewings. One way to control the aphids is to put a sticky material such as tree banding gum around the base of the plant to prevent the ants climbing up to the aphid colonies, leaving them exposed to predator insects.
Do not over fertilize or heavily prune woody plants as both produce fast growing succulent shoots that aphids love. If you only have a few aphids the shoot they are on can be cut off or they can be sprayed off with a jet of water, they are not good at climbing back onto the plant. Ladybugs love to meet aphids, if you don’t have any you can purchase some to release in your garden. If necessary spray with insecticidal soap or pyrethrins. Some organic spray mixes contain both compounds. Some aphids overwinter as eggs on trees and shrubs, a dormant spray of Horticultural Oil will reduce the populations of these aphids.
Cutworms are fleshy, striped and variably colored caterpillars that climb up plants to feed at night, and rest in the soil at the base of the plants during the day. Some cutworms will fade during the day if there is adequate cover from the leaves of the plants. Cutworms may change from green to a dark colour as they grow at age. They measure up to 4 cm long as full size larva and curl up when handled or disturbed. Look for stems that are cut off at the base, or chewing injury on stems, leaves and buds in early spring.
Handpick cutworms from plants after dark and destroy those found in the soil around the base of the plant during the day. Splashing a pale water containing a quarter cup of dishwashing liquid on the ground around the plants will often bring the cutworms to the surface during the day. If a spray is required apply at dusk when the cutworms are likely to be more active. Bacillus thuringiensis (BT) will kill very small cutworms. BT will only work if cutworms feed on plant material treated with this product. Pyrethrin is a contact insecticide and it will control both small and large cutworms.
Leaf Rollers are 10 to 15 types of small caterpillars of many different colors that feed on buds, leaves and fruit from the first signs of plant growth in the spring through to mid-summer. This insect are typically pests of trees and shrubs and they are most active in April May and June. Some feed individually and others are in colonies. Some rolled leaves up and others feed on the upper or lower surfaces of unrolled leaves. Some of these insects cause significant damage but most are just annoying.
Leaf Roller Control
Some of the leaf rollers and related caterpillars overwinter on the shrubs and trees. Population of these insects can be reduced by applying dormant oil to the shrubs and trees before they start to grow in the spring. Once there was growth on your shrubs and trees check for them every week looking for insects themselves and rolled leaves that they may be inside of. If there are only a few can pick and destroy them. Bacillus thuringiensis (BT) is one of the best controls for most of these insects. BT must be applied to actively feeding insects to be effective. Pyrethrins is also a very effective control product. If the insects are protected inside rolled leaves it may be difficult to control them with either product.
Did you know? the adult of most caterpillars are moths. There is one insect is larva look very similar to leaf rollers but it settled is a beetle, this is the Viburnum Beetle. Check which plant the insect is feeding on before sprain them because BT does not work on beetle larva. Pyrethrins would have to be used on this insect.
Slugs are softbodied pests, from tiny to 10+ cm long. Look for slime trails on leaves and on soil. They shelter in moist, dark spaces during the day and feed at night. They are active throughout the year of temperature and humidity is suitable, especially after rains in the spring and fall. Surface tissues of the plants are rasped, and irregular holes are eaten in the foliage leaving it slimy and tattered. Seedlings may be completely eaten and blossoms on flowering plants may be severely damaged.
Slugs can be handpick or caught in special traps. Pelleted slug bait’s can be placed the garden around plants and in dark areas where they take shelter. Baits should be replaced every few days, especially after rains. Diatomaceous earth will also control slugs. Slugs hate copper, copper tape can be placed around the base of individual plants or pots to prevent them gaining access to the.
Root and Vine Weevils
There are five or six types of weevils and the adults range from 3 to 10 mm long and are grey to black in color. These primarily nocturnal pests attack many types of berry and ornamental plants. Root weevils larva or grubs feed on roots, seriously weakening or causing them to die. The snout- nosed adult beetles feed at night on the edges of leaves giving them a notch appearance, because of the type of mouthparts these insects have they cannot make holes in the middle of the leaf. Adults can be found all year long, but each type has a specific activity. Some feed on new growth and April, and some emerge and feed from late June onwards. Larva can be found year-round in the soil for plant crowns.
Root and Vine Weevil Control
Place short pieces of board or cardboard among the plants, weevils will hide under these and can be collected and destroyed every few days. At night at all weevils can be shaken off plants over ground sheet collected and destroyed. One of the best biological controls is the use of parasitic nematodes. At all weevils can also be controlled with the application of pyrethrins, it should be applied at dusk for best results.
Earwigs are insects are about 1.6 cm long, dark brown, with a pair of pinchers at the rear end. They are predator insects on other insect pests and usually only caused minor damage to garden plants, even if they are annoying. They can chew holes in leaves and sometimes feed on right peaches apricots and nectarines. Most damage occurs at night because earwigs hide in soil crevices or debris during daylight hours.
since earwigs are active at night, they can be trapped in rolled newspaper or corrugated cardboard placed near the plants overnight. They crawl into the traps and at sunrise you can drop them into bucket of soapy water or put them in the freezer to kill them. Spray. Is required spray the area with insecticidal soap, insecticidal soap plus pyrethrins, or dust with diatomaceous earth
These insects are rarely a past to plants, in fact they are beneficial insects feeding on other insects. Most questions about ants are about large carpenter ants (8 – 15 mm long) that can cause significant damage to homes and very small that are a nuisance when they get into homes. Carpenter ants need to be properly identified, and if they are in a home, a pest control company should be hired to control them. Small nuisance ants nest outside in venture into homes to find food
In the home, wash counter tops and inside cupboards with soap and water to eliminate any source of food. Keep food in lightly covered containers. Don’t leave more than one day’s pet food out. Rinse containers that are to be recycled. Destroy ant trails by washing with soap and water. Set out and traps and bait in areas of high activity.
These are sucking insects that feed on a wide variety of plants. Common scale the Fraser Valley can be from 1 mm to 5 mm across. Lecanium scale are the largest a common on ornamentals and some houseplants. Scale overwinter under small bumps or shell like structures of various shapes on plant branches. During the winter these bumps are filled with eggs, and in the spring these eggs hatch, the shell lifts and large numbers of tiny crawler insects in cottony fluff emerge and move all over the plant. After mating the female starts to suck the sap of the plant and forming a new shell over top of her body. By the fall her body degenerates into a mass of eggs ready to overwinter.
If you only have one or two plants rub the scale off rub off with fingernail or use a toothbrush. Prune out heavily infested shoots. During the dormant season woody plants can be sprayed with Horticultural Oil. Once the crawlers have hatched but have but the females have not yet formed new scales over their bodies, they are easy to control with insecticidal soap or pyrethrins.
Spider mites: these are tiny spiderlike animals, barely visible without magnification. There are several different kinds that affect both health and vigor of a wide range of plants. The feeding action of some mites can cause foliage to turn pale green to a bronze appearance. The pear blister mite causes a series of red small blisters on the underside of pear leaves that turn brown for the during summer. Some mites form webbing and some and some do not. Spruce spider mites causes needles to become yellow and covered with a silky webbing. This common might also attacks Juniper, Thuja and Tsuga.
Spider Mite Control
Predator mites are important control mechanism for mites. Fungicides and insecticides containing sulfur are very damaging to predator mites, use these products with caution. Some mites such as the two-spotted mite on fruit trees can be partially controlled by washing them off the trees with a spray of water. The population of most mites can be reduced by an application of horticultural oil in the dormant season. Pyrethrins can be used to control mites in the summer time, but these also will damage predator mites.
Mealybugs are insects that are tiny, woolly, white insects that resemble little bits of fluff. A wide range of plants can host mealybugs They are found on stems and the undersides of leaves, especially where the plants branch. They suck plant’s sap and produce honeydew on all parts of the plants. Honeydew attracts ants and can cause the growth of sooty mold. Affected plants appear unthrifty, yellow, wilted, or deformed and can die from the infestation. Every generation every 30 days and can have up to eight overlapping generations each year. They were common pests of succulents.
Mealy Bug Control
Wipe off with Q-tip dipped in rubbing alcohol or spray rubbing alcohol on the plants. Insecticidal soap and pyrethrins will control this insect.
Organic Control Products Available at Art's Nursery
Insecticidal Soap - Aphids
Pyrethrins and Pyrethroids - Leaf Rollers, cutworms, aphids
Bacillus thuringiensis (BTk) - Leaf rollers and cutworms
Copper Tape - Slugs
Diatomaceous earth - slugs, cutworms, leaf rollers, aphids
Iron (ferric phosphate) - slugs
Horticultural Oil - Aphids, mites, leafrollers, scale
Sulfur and Lime Sulfur - Mites
Beneficial Insects - see our beneficial insects reference page