Five Garden Pests (and what to do about them!)

If you’ve spent any time growing plants either indoors or outdoors, you know one of the most frustrating things to deal with is pests. When working with plants, some pests can be unavoidable, whether in the house or the yard. They co-exist within nature, after all, and we are in their space as much as they’re in ours.

It doesn’t mean we need to be happy about it. 

I’ve dealt with a lot of pest issues (minor and major) on my houseplants, and one thing I’ve learned is that, left untreated, tiny pests can create a lot of trouble. Today we’ll go over some of the common garden-variety pests that we face here in Saskatchewan. 

One of the most important considerations here is the understanding between chemical and natural solutions. Especially in the context of edible fruits and vegetables, as well as protecting the natural flora and fauna living in the garden. Many pesticides can be harmful to other critters and to us. 

Aphids

We’ve all seen them—tiny and pale green, but they can cluster en masse. They especially like the sap from new leaves and shoots, and can often be found on the underside of leaves. Aphids can cause curling and yellowing, or kill off leaves altogether, leaving the plant worse for wear. They also leave a sticky mess on leaves, which can attract other insects. 

A good way to deal with aphids is by introducing ladybugs, who prey on aphids. A strong blast of water can dislodge them, or a heavily-diluted mixture of water and dish soap can prevent them from spreading. Neem oil, a natural seed extract, can also be used in a spray to ward them off. During hot conditions, be sure to spray leaves at dusk to prevent them from scorching. 

Flea Beetles

Flea beetles are a collection of specific beetles, each which causes harm to a specific plant. For instance, crucifer flea beetles feed mostly on young cruciferous crops like broccoli, kale, and horseradish, while potato flea beetles feed on the leaves of potato plants. These pests are particularly active in the early season, and can cause significant harm to vegetable plants. In the case of plants like kale or cabbage, flea beetles can cause the plant to be inedible. 

Transplanted crops are less vulnerable to flea beetles than direct seeding. Early in the season, when flea beetles are active, cover newly seeded plants with row covers to deter infestations—as soon as they are planted. Keep growing areas watered and weeded, and water at mid-day to discourage them, as these beetles like hot and dry conditions. Some people plant “trap crops”, meaning something grown as a decoy to distract the flea beetles from more valuable or desired crops. Certain beneficial nematodes assist by targetting the larvae in the soil, but they will not kill the adults. 

Lily Leaf Beetles

These pests are distinctive due to their bright red colouring, and particularly frustrating because they do a lot of damage without any simple deterrents. Lily leaf beetles eat the leaves, stems, buds, and flowers of lilies, during both their larval and adult phases. Adult lily leaf beetles hide their eggs in small clusters on the underside of leaves, and can lay hundreds of eggs in a single season.

Prevention and control of these pests is laborious and requires a watchful eye. The eggs and larvae must be located and destroyed, and the adults picked off one by one and crushed. Products containing neem oil may be beneficial without causing significant harm to plants or other insects. In some cases, row covers may help, especially during the early part of the season as lily beetles overwinter in the soil and emerge in early spring.

Cutworms

Cutworms are a group of nocturnal caterpillars that cause damage to garden plants, notably including the Bertha Armyworm, which is destructive to canola and flax crops in Saskatchewan. They grow one to two inches long, and chew through the stems of young plants or seedlings just below the surface. Some species target roots, while others are capable of climbing the stalk. 

Cardboard or plastic collars which go around the plant and into the soil have been proven to assist against cutworms. Keeping a bare strip of soil around the garden bed may deter them from crossing it. Subterranean cutworms, as well as their eggs and larvae, may be targetted by certain beneficial nematodes. Diatomaceous earth, a natural powder which doesn’t harm the plant, can kill cutworms by absorbing their oils and causing dehydration, but this is a slower process. 

Root Maggots

Root maggots that cause trouble here in Saskatchewan include several species that attack brassica vegetables as well as canola plants. These are the larval form of flies which lay their eggs near the base of plants. When the eggs hatch, the larvae emerge and feed on the roots of nearby plants. This can cause the plants themselves to grow poorly, lose leaves, and possibly die off due to root damage. These insects overwinter in soil, and thrive in wet, cool environments.

Row covering may work to prevent root maggots, but not if the flies are already in the soil. Removing plant debris in the fall will remove their food source, and rotating crops in different areas will discourage them from attacking the same plants. Diatomaceous earth may work against root maggots in partnership with other methods of control and prevention. Till soil in the fall to expose pupae and prevent eggs from hatching in the spring. 

Hopefully some of the information here might help you deal with whatever sort of pest you’re facing. Until next time!