How to get rid of undesirables from our gardens

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Aliases (earth fleas)

They are small jumping insects, no larger than a pinhead, with shiny brown, black, blue, or copper-red shells (sometimes with yellow stripes), which leap as soon as they sense danger. A severe infestation can defoliate and weaken our plants. Clues of their presence:

many small round holes in the new foliage, which become larger as the leaves develop;
new shoots, young plants, and seedlings gnawed or destroyed.

What to do?

The plants are shaken over a container filled with soapy water to make the flea beetles fall into it.
A powerful jet of water is directed at the plant to dislodge them.
They are captured using a vacuum cleaner (battery operated to avoid shocks).
Sticky traps are placed near the attacked plants.
As a last resort, apply a pyrethrum-based insecticide (choose a product without added piperonyl butoxide, which makes the product very toxic).

How to prevent it?
Put mulch around the base of the plants and keep the soil moist.
Plant mint, thyme, hyssop, catnip, or white clover at the base of susceptible plants.
We install sails to protect our plants before the flea beetles come out (May).
In the spring, entomophagous nematodes, and microscopic worms that will kill flea beetle larvae are introduced into the soil (ask our garden center to find out which ones to use).

Powdery mildew or powdery mildew

This disease caused by a microscopic fungus develops from mid-summer until late fall. It can stunt plant growth but is rarely fatal to adult plants. Clues of his presence:

spots or a thin film of white or greyish powdery down, sometimes sprinkled with small black dots, on the leaves, buds, flowers, and fruits;
in severe cases, leaves curl, dry up and drop prematurely, and flowers and fruits are distorted.

What to do?

• If possible, we prune and eliminate the infected parts (we don’t forget to disinfect our tools with rubbing alcohol afterward).

• As soon as the first symptoms appear, the infected plants are sprayed with a baking soda solution (15 to 45 g of baking soda and 15 to 45 ml of liquid soap in 4 L of water), which does not stop white but slows its progression (it can also be used as a preventive measure if the disease is recurrent).

How to prevent it?

• Choose cultivars resistant to powdery mildew (find out more at the garden center or nursery).

• Apply mulch and keep the soil moist.

• On hot days, spray the foliage with water (early in the morning, never in the evening).

• Plant susceptible species in a sunny spot and not too close to each other. Dense plants are regularly pruned to allow air and light to pass through.

Tracks

There are many species, of varying sizes and colors. They attack our vegetable and ornamental plants, and our trees and shrubs. During infestations, colonies of caterpillars can defoliate an entire plant or tree and sometimes cause it to die. Clues of their presence:

cocoons of silk under the rolled leaves of plants or nests of silken webs in the branches of trees;
small black spots on the leaves, usually those near the ground;
nibbled stems, leaves, or buds.

What to do?

Egg masses, cocoons, and visible caterpillars are picked up by hand and immersed in soapy water to destroy them.
If you notice the presence of a nest, take it down and destroy it (at nightfall when the caterpillars have taken refuge there).
A powerful jet of water is directed at infested plants or nests to dislodge them.
Diatomaceous earth (a fine, sharp powder) is sprinkled around the plants or on the branches of the attacked plants.
When populations are high, a biological insecticide based on BTC (a bacterium that kills young caterpillars) is used.
As a last resort, spray a pyrethrum-based insecticide.

How to prevent it?

If the damage is caused by moth caterpillars, light traps are set which will attract and kill the adults.
If the caterpillars are found in trees and shrubs, sticky bands are placed around the trunks to trap them.

mealybugs

They are tiny insects (often difficult to see with the naked eye), without wings or legs, similar to bulging scales, miniature shells, or flattened gray, pink, or brown discs depending on the species. Some are covered with a waxy cotton-like secretion. They live in groups, motionless, on plants, young twigs, and tree trunks. In large numbers, they can quickly weaken plants. Clues of their presence:

a brown, sweet, and sticky substance (honeydew) on plants;
a blackish, soot-like felting (sooty mold) on leaves and stems;
the presence of many ants around the plant;
leaves or needles that wither and drop prematurely; fruits that stay small and fall off; twigs and branches that wither and die.

What to do?

If possible, get rid of the infested plant (mealybugs can easily spread to other plants); otherwise, we isolate it.
Cut and discard the attacked parts. Then we wash our hands and disinfect our tools with rubbing alcohol.
The bugs are swabbed with a cotton swab dipped in rubbing alcohol to dry them out, or sprayed with a solution of one part rubbing alcohol to seven parts water.
On branches and trunks, rub the infested part with a brush dipped in soapy water or rubbing alcohol to dislodge them; the operation is repeated regularly.
As a last resort, insecticidal soap or a pyrethrum-based product is used.
If sooty mold is present, gently wipe the affected parts with a damp cloth.

How to prevent it?

• We carefully inspect our plants on purchase so as not to introduce them into our garden (this is often how they arrive).

• In the spring, spray dormant oil on plants that are often infested.
slugs

The damage caused by these soft-bodied, shiny gray or brown crawling snails is often greater on young plants than on adult plants. Clues of their presence:

furrows and streaks of slimy mucus and black spots on the foliage and on the ground;
nibbled leaves, petals, and fruit;
gnawed and destroyed seedlings, young shoots, and flowers; fruits and tubers pierced with galleries.

What to do?

Traps are placed near the attacked plants: a glass filled with beer sunk into the ground or an overturned terracotta pot with a few leaves of hosta or lettuce where they will come to hide during the day.
Pick them up by hand and dip them in a bucket of soapy water or sprinkle them with salt.
Surround sensitive plants with an abrasive substance that will serve as a barrier: crushed eggshells, wood ash, coarse sand, or diatomaceous earth.
Copper strips (at least 5 cm) are placed at the base of the plants; the slugs receive a shock from their contact.
As a last resort, iron phosphate granules are used; this kills slugs when they ingest it.

How to prevent it?

A mulch of pine needles is placed under sensitive plants; it will act as a barrier.
Pick up plant debris and other objects that can serve as dark, cool shelter for slugs during the day.
Avoid watering in the evening.
We maintain a good distance between our plants and we prune the subjects that are too dense so that the air circulates well.

Mildew

This fungal disease can spread quickly and cause severe damage. In severe cases, plants can dry out and die. Clues of his presence:

a white powder and a whitish or grayish down on the underside of the leaves, then dark brown burns that pass through the foliage;
leaves, stems, flowers, and fruits that become covered with dark patches and fall off.

What to do?

As soon as the first symptoms appear, the infected plants are sprayed with a baking soda solution (see above, under White), which can also be applied as a preventive measure if the disease is recurrent.
Cut, pick up and discard the infected parts; better to do it in dry weather to avoid spreading the disease. We disinfect our tools with alcohol afterward.

How to prevent it?
• We replace our plants that are too often sick with cultivars that are more resistant to downy mildew.

• Plant susceptible species in a sunny location; a good mulch is applied; they are given space and, when they become too dense, they are pruned to let in air and light.

• Water at the beginning of the day, at the foot of the plants, taking care not to wet the foliage.

• Pick up all debris near infected plants to prevent spread.

 

aphids

They are tiny translucent pear-shaped insects that are green, pink, red, blue, black or gray in color depending on the species. They are found under leaves, at the ends of branches, on young shoots and flower buds of plants, shrubs, or trees. In case of severe infestation, the plants quickly lose their vitality and some parts may die. Clues of their presence:

a brown, sugary, sticky substance (honeydew) on plants;
a blackish, soot-like felting (sooty mold) on leaves and stems;
many ants around the plants;
sometimes, depending on the species, small white cotton wool-like balls or green or colored growths on stems and leaves;
leaves that turn yellow, curl, curl and drop prematurely; withered buds and flowers as well as deformed fruits.

What to do?

Run a gloved hand along the leaves and stems to knock the aphids into a bucket filled with soapy water.
Direct a strong jet of water on the plant to dislodge them.
Cut and destroy the infested parts.
Yellow sticky traps are placed near the attacked plants.
If the infestation persists, insecticidal soap is used.
If sooty mold is present, gently wipe the affected parts with a damp cloth.

How to prevent it?

We plant nasturtiums and petunias along the edges of our flowerbeds. They will attract most aphids, which will be easier to locate and eliminate.
If infestations are frequent, use dormant oil in the spring.

 

Rusts

Different strains of fungi cause rust on various plants, but the symptoms are pretty much the same. Rusts can be fatal to seedlings and cuttings, but rarely to adult plants. However, in the event of repeated attacks, the plant may gradually weaken. Clues for spotting rust:

  • orange-colored pustules or swellings on the undersides of the leaves and on the stems;
  • tumors and gelatinous orange masses on conifers;
  • leaves, needles, and twigs that turn brown, dry out, and drop prematurely.

 

What to do?

  • Prune and discard the infected parts (however, never handle the plant when it is wet to avoid spreading the disease). We disinfect our tools afterward.
  • As soon as the first symptoms appear, the infected plants are sprayed with a baking soda solution (see above, under White), which can also be applied as a preventive measure if the disease is recurrent.

 

How to prevent it?

• Too often infected plants are replaced by more resistant cultivars; once a plant is affected, the rust is likely to return regularly, regardless of the measures deployed.

• Water early in the morning, avoiding wetting the foliage.

• We prune our plants to improve air circulation and promote sunshine.

 

Two-spotted spider mites (red spider mites)

These are mites that look like tiny spiders, often beige, green, or yellow (but rarely red despite their name). Spider mites are almost invisible to the naked eye. To detect them, scrutinize the plant with a magnifying glass or place a sheet of white paper underneath and gently shake it to remove the spider mites. In the event of an infestation, the plants can quickly wither and die. Clues of their presence:

  • fine white webs (like those of spiders); they are seen by spraying water on the infested parts;
  • leaves that turn yellow, taking on a bronze or copper tint, and fall in large numbers.

 

What to do?

  • Cut and destroy the infested parts.
  • A powerful jet of water is directed at the plant to dislodge them.
  • Spray the foliage with water in the morning (mites do not like water).
  • As a last resort, insecticidal soap or a pyrethrum-based product is used.

 

How to prevent it?

• Water copiously in times of drought.

• On hot days, the aerial parts of sensitive plants, shrubs, and trees are sprinkled lightly with water in the morning to maintain a good level of humidity.

• For frequent infestations, dormant oil is used in the spring.

 

Thrips

They are tiny insects with a slender, elongated body and two pairs of feather-like wings that are yellow, brown, black, or white in color. Small and active especially at night, they are difficult to observe. You can place a white sheet under the plant early in the morning and shake it gently to make the thrips fall on it and better observe them under a magnifying glass. In the event of an infestation, the leaves become stunted and fall off, the flower buds no longer open, the fruits are discolored and the plant weakens. Clues of their presence:

  • small black spots on infested plants;
  • yellow spots, then silver or whitish streaks and stripes on the leaves and petals.

 

What to do?

  • We prune and destroy the infested parts (we disinfect our tools afterward).
  • A powerful jet of water is directed at the plant to dislodge them.
  • Sticky traps, preferably blue, are placed near the foliage of the attacked plants.
  • As a last resort, insecticidal soap is used (it will be necessary to repeat the application regularly).

 

How to prevent it?

• We mulch and water our plants well.

• In the spring, spray dormant oil on plants that are often infested.

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