Aphids- Aphids are a sucking insect and can cause distorted buds and leaves. By walking through your garden often you will see signs of pest damage pretty early. Aphids give birth to live babies every few days so it’s important to get a handle on them quickly and do follow up inspections. They are easily dislodged by using a spray of the hose. I know what you are thinking, what if they climb back up? When you knock an aphid off the plant often it breaks their mouthparts so they can’t feed anymore. Aphids come in many colours from green, black and brown and are tiny soft bodied insects. If you only have a few they are easily squished. If you have aphids on your fruit trees, it’s best to apply a dormant oil in late winter to smother overwintering eggs.
Cutworms- Cutworms are thick greyish brown larva about an inch and a half long. They are night feeders and hide under the soil near plants during the day. Their damage is noticeable as they severe the plant just above ground level. They tend to attack early vegetable and flower transplants. To find the cutworms dig around the affected plant to see if you can find it. You can protect your young seedlings by placing a collar around the plant. Use stiff paper such as a waxed milk carton or a plastic pot with the bottom removed, push the edges of the collars into the soil around your seedling. Another option is to plant later in the season to avoid cutworm damage.
Slugs & Snails– Living here on the west coast with our cool wet climate means we deal with slug and snail damage. Once again we have a pest that likes to feed at night but you will also seem them on rainy days. They love moist shady areas. Slugs leave ragged holes and tears on plant leaves and make them look unsightly. Often slugs and snails will leave behind a slime trail. There are all sorts of ways to prevent slugs in the garden from copper barriers on raised beds to using beer traps in the garden. Hand picking slugs from under a board, plant pot, grapefruit rinds or beer traps are effective controls in the garden. Practice good garden sanitation. Slugs like to hide under debris in the garden. If I had a pile of old leaves around the base of a plant I can guarantee there will be some snails or slugs hiding in there.
Cabbage Butterfly larva-I’m sure most of you have seen the cabbage butterfly. She starts to appear in April and has white wings with a black dot on each wing. She lays her eggs on plants in the Brassica family. This includes plants like broccoli, cabbage, kale, collards, cauliflower, turnips and Brussel sprouts. Once the eggs hatch tiny green larva start to eat the leaves of plants. There are 2-5 generations each season so this pest can be quite damaging to your crops. To control the cabbage butterfly you need to add a floating row cover over the whole crop at planting time. This lightweight fabric will prevent her from laying her eggs but it allows water and sunlight to pass through. It must be applied so that there is enough fabric to accommodate the growing plants and must be held down firmly around the edges. Once your plants have matured they can tolerate a bit of damage.
Leafminer– Leafminers are the larva of a fly that is often too small to see. The fly lays her tiny white eggs on the undersides of leaves of spinach and chard in the garden. The larva mine the inside of the leaf leaving blotches or squiggly lines along the leaf as they move. The easiest way to deter this pest is to use a floating row cover at planting time. I plant my seed and place the cover over. If you wait until the plant starts to grow it may be too late. If you haven’t used row covers, remove affected leaves as you see them. You can either freeze the leaves to kill the pest and them compost them or place them in the trash. Leaf miner has 2-3 generations per season.
Wireworm– Wireworms are the larva of the click beetle. Wireworms feed on tubers of potatoes and the roots of other plants. Wireworms are very common in new gardens that used to be grass. To test your soil for wireworms, you want to use a raw potato for bait. Take a chunk of raw potato and poke a skewer into it. Insert the potato in the soil in early spring before planting begins. Leave the skewer poking out of the soil so you can see it and check it weekly for wireworms. Repeat for several weeks to reduce the population of wireworms. The larva are a yellow colour and if you check your potatoes at harvest damage is seen by all the tiny holes in the potato where they tunnelled. Wireworms can live for 2-6 years so its important to practice good crop rotation. Try to plant potatoes in a different area each year.
Flea beetle– Flea beetles are tiny black insects about the size of a pinhead so they can be hard to see. Flea beetle damage is identified by its shot hole appearance on leaves. Their larva also feeds on the roots of plants. New seedlings are the most susceptible to flea beetles. Again this is another case where floating row covers are used to prevent this insect pest. You can use a white sticky trap in early spring to detect their presence. I find that the flea beetle loves vegetables such as pac choi, beans, beans, beets, broccoli, cabbage, and radishes. They overwinter in the soil so practice good crop rotation.
Keep the garden tidy. If old debris is removed there are less places for pests to hide.
Practice crop rotation to avoid pest and disease problems.
Use plant barriers such as plant collars and row covers to prevent pests.
Walk your garden daily to check your plants. A stressed plant is more susceptible to pests.
Make sure your garden goes into the night dry. Water in the morning. This prevents disease problems on your vegetables.
Don’t plant too early. It may seem warm outside but the soil could be too cold. Cold temperatures slow and even stop plant growth. Learn which crops can withstand cooler temperatures and which ones need to wait until it warms up.