Grow Your Own: 3 garden pests and how to manage them
In loving memory of my tomato that was tragically eaten by a mystery bug.
This week I finally got a small harvest from my tomato plant, but not before some unseen bug got to one and ate the whole thing. This tomato plant has had a stressful life, struggling in a spot on the balcony that wasn’t quite sunny enough, before being moved to the carpark where its first red fruit fell victim to this bug (at least I can tell myself I’m supporting the car park’s ecology).
Here’s a quick tip - pick your tomatoes as soon as they start to blush (turn yellowy-orange) and stick them in a sunny spot inside where they’ll finish ripening in the safety of your home. This works well but ideally we want to manage pests and diseases before they become an issue.
So, here are three common garden pests and what to do about them.
Aphids
Aphids are small, soft-bodied insects that come in a range of colours from green to yellow to black (depending on the species). They can cause damage to plants by sucking the sap from new shoots and tender parts of the plant.
They also excrete something called honeydew as they go, which can then attract other pests like ants and a fungus called sooty mould. In small numbers they won’t do much harm but given the right conditions they can multiply quickly and cause havoc in your garden.
Because they’re so small you may not immediately notice them, but look out for warning signs like plant leaves curling over or yellowing, and dead or stunted shoots. You’ll find them hiding out on the underside of the leaves.
Luckily, they’re not too hard to manage. If your plant is sturdy enough (or its a small tree), you can simply spray them off with a strong stream of water. For more delicate plants you can pick them off by hand. Because the aphids have soft bodies they’ll get squished very easily - end of aphid problem.
If that doesn’t work you can try other natural solutions like neem oil. This can be sprayed to repel larger infestations, but it’s not the best solution as it can also repel other beneficial insects.
Speaking of beneficial insects, the best way to manage aphids is to prevent the population building up in the first place! Aphids happen to be a ladybug’s favourite food (or so I’ve been told), especially in their larvae stage. Plant pollen-rich flowers in your garden like calendula, marigolds, or even some herbs like dill to attract more ladybugs. Birds will also eat aphids, and more bugs means more birds so the way to deal with aphids is… more bugs!
Slugs
Slugs and snails are another common garden intruder that can hurt your harvest. Unlike aphids, who can cause a lot of harm to your plants, slugs don’t necessarily harm the plant so much as just eat the whole thing.
There’s also an easy way to tell if the unseen thing chomping on your leafy greens is a slug or a caterpillar. Caterpillars can only eat leaves from the edges inwards, but slugs have file-like mouths that allow them to eat holes out of the middle of a leaf.
One prevention method is to make sure your garden bed isn’t too moist. Using drip irrigation rather than a hose or overhead sprinklers can help here. You should also remove rotting logs or pieces of wood that they like to live underneath.
If you’ve got a slug problem, it’s once again time to call in some help in the form of natural predators. There’s a great quote from Bill Mollison, one of the founders of permaculture, that “you don’t have a slug problem, you have a duck deficiency”. Ducks and chickens love to eat slugs, as do wild birds if you don’t have the space to keep poultry.
If your local bird population isn’t exactly thriving you can also setup a beer trap. To do this, bury an open container up to the rim and fill it with a few centimetres of beer. The slugs will do the rest, all you need to do is clean it out and replace as needed.
Powdery mildew
Now this one isn’t exactly a pest, but it’s close to my heart - it’s the thing that originally forced the tomato plant to move from the balcony to the car park and ultimately started its demise.
Powdery mildew is a type of fungal pathogen that can spread easily from one plant to the next. It often appears in warm, humid environments. I think it took hold on the balcony because of the lack of direct sunlight, meaning moisture wasn’t evaporating quickly enough leaving the soil damp and warm.
It appears on plants as a white powder on the leaves and can cause yellowing, normally on lower leaves first and then spreading to other parts of the plant. To prevent it, you can try spraying your plants leaves with a mixture of one part milk to five parts water every week or so. You should also avoid overhead watering to keep the leaves dry (I wrote more about watering properly here) and make sure you leave sufficient space between each plant. Pruning can also help to improve airflow and keep humidity down.
If it does take hold, there are a few organic treatments you can try (this article has a good overview of the options) but I didn’t personally have much luck, so if you’ve got any suggestions I’d love to hear them!
I’ll be back with another interview next week with a great local farmer who’s a regular at the Mulgrave Farmers’ Market. We had a great discussion about what got him started in farming, and some of the social benefits that come from knowing your food and growing locally. Check back next week for more!