What Are Aphids?
With the onset of warmer temperatures, aphids are making their presence known in the garden. Aphids are small, pear-shaped soft-bodied insects that are found in almost any zone. Aphids reproduce quickly, so immediate control is critical.
The various species can be white, black, brown, gray, yellow, light green, pink and some have a woolly or waxy coating. Adults are typically flightless, but most develop wings when there is an increase in population creating competition for food. These winged aphids fly to other plants to start a new colony. Aphids most often feed in large numbers, but they have been observed to feed singly or small numbers.
Nymphs and adults feed on the juices of new succulent leaves, stems, buds, flowers and fruits depending on the species. Their feeding activity results in misshapen, curling, yellow or stunted leaves. The leaves may also be covered with a sticky substance referred to as honeydew, a waste product produced by aphids feeding. Honeydew attracts ants as it is a food source for them.
Honeydew-covered leaves sometimes develop a fungal growth called sooty mold causing them (and nearby branches) to turn black. Aphid feeding activity can cause flowers or fruit to become distorted, cause galls to form on leaves or roots. Aphids also may transmit viruses to plants by their feeding habits.
How To Get Rid Of Aphids
Spraying cold water on the leaves is often enough to dislodge the aphids. You can also use Safer’s insecticidal soap or 3-in-1 Garden Spray. Beneficial insects such as lady beetles feed on aphids. Introducing nasturtiums to a garden will attract beneficial insects that feed on aphids.
Boxelder bugs are common pests across much of southern Canada and the United States. Thankfully, they do very little damage to the trees they attack, however their presence can begin to be a nuisance if they are left to their own devices.
Appearance and Habit
As adults, Boxelder bugs are about ½” long with bright red or black colouration along with narrow red lines along their backs. They principally feed on Boxelder trees, but can sometimes be found on other plants as well. They feed by sucking water and sap from tender parts of the affected plant. They rarely do any lasting damage to the plant but the signs of attack – puckering of the leaves or leaf gall (raised bumps on the leaves) are unsightly.
When these pests build up to a large population, they are often spotted in the fall when they retreat into homes seeking shelter from cold temperatures. They are only pests by their presence, though if they are threatened they may bite, causing slight skin irritation.
In the fall, Boxelder bugs seek shelter in protected places like cracks or crevices in walls, doors, and windows, particularly on the south and west side of your house. They will hide in these locations inside or outside the home until the spring, when they emerge to seek out host trees upon which to feed and lay eggs.
Eliminating Boxelder Bugs
Once these pests become established in the home, there are very few treatment options. Safer’s Insecticidal Soap will kill them on contact but it has to be sprayed directly on the bugs. Often your best weapon is the liberal use of a vacuum cleaner.
Prevention truly is your best defense. Use fast-acting, short-lived insecticides such as End-All, Trounce, Ambush, or Bug-X outdoors at the first sign of these insects. Check and spray around eaves, attic vents, windows, doors, under-fascia lips, soffits, siding, and any other possible small points of entry. Focus your efforts on south and west sides of the building. Focus less on shady areas; Boxelder bugs rarely frequent shaded sections of the house. Sealing the bugs out by caulking cracks and fixing screens is also an effective means of prevention.
Many common non-insectoid garden pests are difficult to force out of our yards (especially when we’re keen not to harm them and instead just drive them away!) Here we’ll provide some guidance on repelling common garden pests, with a focus on mammals such as rabbits and deer.
Bobbex is a product that repels deer, squirrels, rabbits, chipmunks, groundhogs, and voles. It is harmless to plants and wildlife including humans, pets, birds, and aquatic creatures. It makes the plants unpalatable to most wildlife with a strong scent that bothers many common mammalian pests.
Acti-Sol 5-3-2 Hen Manure
Acti-Sol is a great squirrel repellant, and is a fertilizer as well – sprinkle it in patio pots and around tulip bulbs to protect them from being dug up. Squirrels also avoid alliums, daffodils, and hyacinth bulbs.
Plants That Deter Cats
Cats generally avoid strong-smelling plants (aside of course from catmint!) including:
- Curry plant
- Lemon balm and lemon thyme
Plants That Deter Deer
Note that in the winter, a sufficiently hungry deer will eat just about anything – there are no truly ‘deer-proof’ plants. However, there are several plants that deer will avoid until they have no other choice.
Deer generally avoid poisonous plants, strongly scented plants, thorny or spiky plants, and a couple of other plants that don’t necessarily fall into the other three categories. These plants include:
- Alliums, daffodil, foxglove, monkshood, and poppies
- Basil, bearded iris, catmint, dill, lamb’s ear, lavender, oregano, sage, and salvia
- Barberry and fiveleaf aralia
- Bleeding hearts, Carolina allspice, and rose-of-sharon
Plants that Deter Mice
Mice generally do not like strong odours. Consider planting the following to repel them:
- Basil, euphorbia, mint, rosemary, and wormwood
Plants That Deter Rabbits
There’s an assortment of annuals, perennials and bulbs that rabbits will pass over. Like many other small herbivores, they avoid strong scents, thorns, and poisonous plants, such as:
- Ageratum and verbena
- Columbine, daylilies, echinacea, and periwinkle
- Alliums, daffodils, or hyacinths
- Basil, catmint, dill, oregano, rosemary, and salvia
Plants That Deter Raccoons
Raccoons generally avoid a number of plants, including:
- Habanero peppers, tomatoes, or anything in the nightshade family
- Cucumbers, pole beans (specifically Kentucky Wonder), pumpkins, and squash
- Globe thistle and oriental poppies
Plants That Deter Mosquitoes
They aren’t mammals, but they sure are pesky! The following plants may repel mosquitoes (but it may vary from household to household): basil, catnip, citronella, garlic, lavender, lemon balm, lemon grass, marigolds, pepperming, and rosemary.
We have come to rely on impatiens (Impatiens walleriana) as the “go-to” annual plant that will brighten and add colour to the shady nooks in our gardens and add interest to our container plantings. Perhaps no other bedding plant has ever enjoyed such popularity.
However, during 2013, many gardeners noticed strange things happening to their impatiens, such as yellowing leaves or a “downy” greyish film on the underside of the leaves. These are the first symptoms of downy mildew. After those first signs, the flowers and leaves drop until only the stems are left, leading to the plant’s collapse.
Van Luyk’s is committed to the success of our customers’ gardens and as a result of the existence of downy mildew on impatiens walleriana in Ontario and beyond, Van Luyk’s is not growing impatiens this season or in the foreseeable future.
All traditional varieties of impatiens (impatiens walleriana) are susceptible to downy mildew; however, New Guinea impatiens (impatiens hawkeri) and their hybrids have fortunately shown themselves to be highly resistant to the disease. So gardeners can consider upgrading to the showier, larger-flowered cousin of this garden favorite. You can also consider other shade-loving and downy mildew-resistant plants like coleus or begonias for your flowerbeds.
What is downy mildew?
Downy mildew is caused by an organism called Plasmopara obducens or water mould.
How does the disease spread?
Downy mildew is spread by spores located on the underside of infected leaves. The spores can be spread by wind or rain as it splashes onto the leaves. The organism is a water mould requiring moist conditions to develop spores and cause new infections. Areas of deep shade where foliage stays wet for a long time tends to have a higher incidence of the disease.
Are all impatiens susceptible to downy mildew?
No. Downy mildew attacks only Impatiens walleriana. Other types, such as New Guinea and SunPatiens, are not affected.
Are there any chemical controls that can be used?
There are no fungicides available to gardeners for the control of this disease.
How should I dispose of infected plants?
Do not place infected plants in home composters in case the spores overwinter. Instead, bag and put them at the curb to be composted in a municipal facility (where the heat is high enough to destroy the organism). Alternatively, you can burn or bury the affected plants deeper than 50 centimetres (20 inches).
Should I plant impatiens next year in soil that once grew infected plants?
Experts advise against planting Impatiens walleriana where infected plants once grew. If you want to grow impatiens in a container that previously held infected plants, thoroughly wash the container with soapy water and a drop of bleach. Be sure to use fresh planting mix. Because the disease is specific only to Impatiens walleriana, you can grow any other bedding plants without any risk.
Should I avoid buying bedding impatiens (Impatiens walleriana) for my garden this year?
Because downy mildew is a relatively new problem, whether it becomes more serious or not remains to be seen. The best advice is to be informed.
Alternatives to Impatiens walleriana
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Euonymus scale is a pest that covers the stems and foliage of many hardy shrubs and sucks the fluid from the branches of the plant. Small infestations can stunt the growth of the plant and leave it susceptible to other pests and diseases, and larger infestations can kill an entire plant over one growing season.
There are a several simple methods of prevention but very few effective measures of treatment. Early identification of the pest is crucial. If more than ½ of a plant is covered with Euonymus scale, we usually recommend immediately removing the plant in its entirety; heavy infestations are extremely difficult to control.
Mature Euonymus scale looks like a very small white or greyish insect often found on the stems and leaves of a variety of plants, but especially on evergreen Euonymus. The greyish adult females are about 2mm long and look like an oyster shell. The males are smaller, narrower and white. It is the male that gives the branches a snowy appearance. The crawler is orange/yellow in colour.
When Does It Appear?
In the early spring, eggs are laid by mature females. Eggs hatch late May to early June over a period of 2-3 weeks, and the new crawlers migrate to the leaves to feed. They may also be blown by the wind to other susceptible host plants. In particularly bad seasons, a second generation can appear in mid-July.
Eliminating Euonymus Scale
Euonymus scale has three stages in its life cycle: Egg, crawler, and adult. By the time scale matures to the adult stage, it has developed thick armour that protects it from most sprays. Thus, the only time it can be effectively sprayed is during the crawler stage.
Truly, the best treatment is prevention. Generally, Euonymus or other potential host plants are far more susceptible to scale infestations when they are stressed for other reasons. Keeping your plants healthy will almost completely eliminate the chances of a scale infestation.
To ensure your Euonymus is in top shape, follow these simple rules:
- Avoid planting your Euonymus close to a building; these locations tend to get exceedingly warm and dry in the summer, greatly stressing the plant
- Keep the plant well-watered during hot spells in the summer
- Fertilize annually with a balanced, liquid fertilizer (20-20-20 is suitable)
- A layer of mulch around the roots can help keep the soil consistently moist
What if I still get it?
It’s possible, though unlikely, that a plant kept healthy will still contract scale. If your plant has scale, the only method of treatment is an application of Horticultural Oil. Since the crawler stage is the only time the scale is susceptible to spray, this treatment can only be done just before crawlers appear. The spray is applied when the plant is still dormant, in early spring before the leaf buds show green tips. Further instructions:
- Only spray when a minimum temperature of 4 degrees Celcius is expected for the next 4 to 5 days: freezing conditions may cause the oil to injure treated plants
- Spray during dry mornings; the product must dry on the branches and leaves to be effective; it cannot rain for several hours following application
- Spray the stems, foliage, and undersides of the plant until it is dripping
- Shake your sprayer frequently to avoid having the oil settle or separate from the water
You can also gently scrape infested branches with your hand or a blunt object at any time of year in order to mechanically remove some of the insects; take care not to damage the bark of the plant in the process.
Scale can sometimes winter over in the top layer of soil around the infected shrub. Removing an inch off of the soil around the plant and replacing it may help to reduce populations the following year.
Other Susceptible Plants
Euonymus scale most often affects Euonymus, but if left untreated it can spread to several other plants as well:
- Burningbush (this in fact is a deciduous type of Euonymus)
- English Ivy
- Spurge (Pachysandra)
The Japanese Beetle was inadvertently introduced to Eastern United States in 1916 and in 1939 discovered in Canada in the Niagara Peninsula. The beetle has spread to other provinces due to the fact that there are no natural predators for this species.
The Japanese beetle is approximately 1 cm long with a metallic green body and bronze-coloured outer wing coverings. It has small tufts of white hair along the sides and back of its body. Larvae (grubs) are white in colour, c-shaped and about 2.5cm long when mature. Adults feed on over 300 plant species and the larva feed on roots of various plants and grasses, often destroying lawns.
The life cycle of a Japanese beetle from egg to adult is one year. Adult Japanese Beetles emerge in early July at which time they feed and mate during warm sunny days. On sunny days beetles start to appear on plants mid-morning and numbers peak mid- to late afternoon.
The life cycle of the adults is short, averaging 30-45 days. During that period the females feed, mate and lay eggs repeating the cycle every 24 to 48 hours. At each egg laying, the female deposits one to four eggs in the soil at a depth of 3 to 5 cm. A female can lay up to 60 eggs in her lifetime.
Larvae hatch in two weeks and begin to feed on roots in the upper 10 cm of soil. During drier periods eggs may be destroyed but the larvae in deeper soil survive. The grubs reach maturity during late summer and early fall when they are found closer to the surface, but once the soil temperature drops below 15oC the grubs retreat downward below the frost line where they will remain until spring. When soil temperatures reach 15oC or above, the grubs will move closer to the surface to resume feeding.
Effective control of Japanese Beetles should be a two-pronged approach which entails controlling the adult and larvae numbers.
Adults can be hand-picked or knocked into soapy water. This task is best performed in the early morning at which time the adults are sluggish. Consistent hand-picking is helpful in reducing numbers and damage to plants.
Using row covers is another great method of reducing damage caused by the beetles’ feeding activity in a vegetable garden. The row covers have the added benefit of deterring other insect pests that typically damage vegetable plants.
Pheromone traps may also be used to control numbers, but there are two schools of thought with regard to the traps: it is believed that the traps may attract a greater number of beetles to a garden, thus increasing feeding damage. If traps are used to control the beetles, then it is recommended that they be placed as far away as possible from plants that the beetles find tasty.
The larvae numbers can be controlled by an application of Nematodes (specifically heterorhabditis bacteriophora) in May while the grubs are close to the surface. A second application in September can help to reduce the number of newly-hatched grubs that are small and feeding close to the surface thus eliminating the number of larvae reaching adulthood the next year.
Hot droughty summers help by destroying the eggs and killing young larvae as they require soil moisture for survival. Irrigated lawns have much higher grub populations than non-irrigated lawns.
Moles are garden pests. In particularly bad scenarios lawns and some plants may be seriously damaged by them. Worse still, a mole problem left unaddressed can lead to issues with voles, true rodents that can cause catastrophic damage to your garden.
Is it a Mole?
If you’re certain there is a critter running around your yard but you haven’t yet spotted it, you’ll need to ensure that you’re addressing the right pest. Moles are vaguely mouse-like creatures, though they grow larger, around 15-20 cm long. Their most notable feature is their hands, which are polydactyl (six-fingered). Moles spend most of their time in underground tunnels which they dig using their powerful forelimbs. Moles do not eat plants – they are carnivorous, feeding mostly on grubs, insects, and worms.
Although moles will ignore your plants, their digging often causes collateral damage. Their tunnels can disturb the roots of established plants by exposing them to air. As well, molehills will rip patches of your lawn apart, leaving unsightly craters. Thirdly, mole tunnels close to the surface can partially or completely collapse during heavy rain, causing depressions to appear in your yard. Finally, the more malevolent vole often hijacks existing mole tunnels to feed on the roots of your precious plants.
The most obvious indication of a mole problem is a mole hill. Evidence of mole activity is more predominant in the spring and fall, particularly after periods of rain. Thankfully, moles are solitary creatures and are fiercely territorial. Unless it is mating season (early to mid-spring), you will almost never find more than one in your yard.
There are two means of controlling moles: trapping and repellent. Mole traps are available at many hardware stores.
If you prefer a less confrontational solution, a strong-smelling product called Critter Ridder works well as a repellent. Be aware that after a few months moles may become accustomed to the smell — in some scenarios, then, the repellent is only a temporary solution.
Nematodes are virtually microscopic natural organisms that are already present in our soil. They are not pests, but prey on other garden pests giving us a natural means of control. Concentrated amounts of nematodes can be used to eliminate grubs from your lawn. Environmentally friendly and safe for children, pets and wildlife, they are perfectly safe to use in any planting situation, including food crops.
How They Work
Nematodes are aggressive organisms that attack the pests by entering natural body openings. Once inside, the nematodes release bacteria that quickly kill the host.
It doesn’t stop there: the nematodes reproduce inside the dead pest and release a new generation of hungry nematodes which disperse to hunt down further prey. This life cycle continues until the pest population has been significantly reduced, at which point the nematodes die back to their natural population levels.
Storing Your Nematodes
- Keep the sealed pack in the fridge so they remain inactive, ensuring their good health until you need them
- Nematodes will keep up to the expiry date, clearly marked on each sealed pack, when kept refrigerated
- They are perishable so you should not open the pack before you intend to use it
- It is always best to use living products as soon as possible after purchase
When To Apply
You must apply nematodes when the soil temperature is between 14 and 33°C (57-91°F). Any colder and they will not break dormancy; any hotter and they will die before they can be effective. Nematodes are very sensitive to UV (Ultraviolet) light. Avoid spraying when it is very sunny.
Avoid fertilizing for two weeks prior to and after nematode application; their life cycle can be disrupted by high nitrogen content in the soil.
Beneficial nematodes are very easy to use. Mix the nematode sponge with water and simply spray or sprinkle the mixture across a broad area where the grubs or other pests are located. You should let the sponge soak in the water for a few minutes prior to use, and shake or stir the mixture to break apart any large lumps that form. Ensure that the ground is slightly moist before you begin as well – this will help the nematodes to get deeper into the soil where grubs lie hidden. You can use a watering can or a sprayer to apply it.
If you use a sprayer, here are a few tips:
- Use maximum pressure to avoid blockages
- Ensure you remove any sieves in your sprayer for the same reason
- Make sure the spray nozzle you use is at least half a millimeter
- Keep shaking the mixture frequently to prevent all of the nematodes from sinking
Cultural Control of Grubs in Lawns
Aside from the liberal use of nematodes, there are a couple other practices that can help reduce the grub population in your lawn.
To minimize the damage caused by feeding grubs, mow your lawn to a height of 3-5 inches. Grass that is cut higher in this manner will be healthier. To that same end, water your lawn less often, but when you do, water thoroughly and deeply. This will encourage your grass to develop deeper, more extensive root systems that will better be able to weather a grub attack.
Be aware: it is perfectly natural to have a small population of grubs in your lawn. Don’t fret if you see one or two. Generally, treatment is warranted if there are more than 5-10 grubs per square foot. Anything less is nothing to worry about!
Powdery mildew is the Common Cold of the plant world. It shows up whenever external conditions such as dry soil, moist air, overcrowding, shade and stagnant air favour its development. It is important to note that in just about every case, mildew is not an indication of a sickly plant.
Mildew is a highly infectious fungus, able to spread rapidly from plant to plant under ideal conditions. The good news is that like a cold, the symptoms are easy to treat but it’s equally important to address the underlying issue causing it in order to prevent it from recurring.
To keep susceptible plants mildew- free in the first place, take the following steps.
- Grow your plants in moisture-retentive soil – do not allow to them to dry out. Mildew prefers moist conditions, but if your plant is stressed from lack of water it leaves it more susceptible to powdery mildew infections.
- Water the roots, not the foliage. Most plants absorb all of their water through the roots. Wetting the foliage creates a breeding ground for mildew, and offers little benefit to the plant itself.
- Allow ample space between plants for good air circulation. Avoid planting close to buildings or fences which block air flow. Mildew prefers moist, stagnant areas.
- If mildew is a recurring issue for certain plants, consider replacing them with more resistant varieties.
- Cleaning garden debris and deadheading spent perennials prevents a source of infection: some mildews are especially attracted to rotting plant material.
If you must spray for mildew, use either garden sulphur or copper sulphate. They are usually available in a powdered form or a liquid suspension. Normally these fungicides can be applied at 7-10 day intervals, and they are highly effective at destroying powdery mildew.