Whether it is an infestation of white grubs or plants (ragweed or poison ivy), there are ecological methods to control them.
Famous white grubs
What is a white grub?
It is the larva of the June bug, European or Japanese beetle. It is white and measures up to 2.5 cm. In its most advanced larval stage, it can cause a lot of damage to your lawn as it feeds on grass roots.
Larvae of the European beetle (source: Bernard Drouin, MAPAQ)
Adult European beetle (source: René Limoges, Insectarium de Montréal)
What are the signs of a white grub infestation?
The damage is mainly visible in the spring and fall. The lawn turns yellow and seems to lack water even when watered. The dead grass comes off in patches like a carpet, under which you can see the larvae.
The presence of holes dug by small mammals (groundhogs, skunks, raccoons, etc.) that feed on larvae and the presence of flocks of birds (red-winged blackbirds, starlings, etc.) pecking the ground is another sign of infestation.
How can I detect them?
Lift your grass off in patches and check for white grubs in the soil, to a depth of just over 10 cm.
How can I prevent infestations?
Firstly, prevent June beetles from coming to lay their eggs in your lawn by following these tips:
- A healthy, diverse and vigorous lawn is more resilient;
- Keep the grass tall (7.5 cm), as this makes access more difficult and hinders the laying of eggs;
- Limit night lighting during the laying period (June-July). Light attracts beetles;
- Space out the watering of your lawn so as not to create a constantly humid environment, suitable for laying eggs.
What are the control measures?
- Encourage the presence of predators, such as birds and small mammals. Replace the clumps of earth dug up by these animals and reseed the disturbed soil.
- You can use entomopathogenic nematodes that will parasitize the white grubs. There is a procedure to follow according to the manufacturer’s specifications. Click here for more details.
- In the event of a major infestation (more than 50% of the grass area damaged by white grubs and/or small mammals) it is preferable to replace the lawn. In this case, you must rake the dead grass down to the soil, collect all visible white grubs and nymphs, and reseed or lay down sod.
Ragweed (Ambrosia sp.)
This weed can reach up to 1 meter in height. It is recognizable thanks to its serrated foliage. Towards the end of July, ragweed flowers produce pollen, which causes hay fever (allergic rhinitis) in people with allergies.
The most effective way to get rid of this plant is by pulling it out of the ground. Its root system is quite shallow, which makes the task relatively easy. This can be done by hand or with the help of tools. It is best to do it in the spring to prevent the plant from blooming and releasing its pollen.
Once pulled, dispose of it in your garbage bin and not in your compost bin, to prevent it from spreading.
Another way to reduce the amount of ragweed plants and the concentration of pollen in the air that causes allergies, is to cut them down twice a year, in mid-July and mid-August.
For more information :
Poison Ivy (Toxicodendron radians)
Poison Ivy can be found in a variety of forms: bushy, creeping and climbing. It grows on the edge of the woods, on wastelands, along roadsides and waterways. Its lustrous leaves are alternate and have three pointed leaflets.
It is important to be able to recognize it because this plant produces a toxic sap containing urushiol, which causes serious dermatitis.
In case of contact with poison ivy, follow the advice on the Portail Santé Mieux-Être du gouvernement du Québec website.
Poison Ivy plants. This species tends to form large tillers.
Cover any part of your body that may come in contact with the sap of this plant.
Take care to wash your clothes separately and several times.
NEVER BURN POISON IVY
The smoke can cause serious health problems or even hospitalization.
Poison Ivy is a very tenacious plant and the eradication process can take a long time. It has a strong root system, which makes pulling it very difficult.
Nevertheless, pulling the plant and all parts of the rhizomes (root) is the most effective way to control it.
For more information:
Portail Santé Mieux-Être du Québec
Allergic Reactions Caused by Poison Ivy
Espace pour la vie website: The Poison Ivy file