Health problems in plants can be divided into 2 categories – Pathogens that cause disease, and Parasites that eat the plants.
I’m really not a big fan of pesticides or chemicals. Actually, that’s putting it mildly…I hate pesticides. They are almost always used too liberally, and often used as a preventative measure rather than to get rid of a problem. But at the same time, I’m not a big fan of caterpillars shredding my fresh new cycad leaves, or aphids sucking the life out of my new buds or snails devouring my lettuce leaves before I get a chance.
So what do we do? Where is the middle ground? Am I supposed to console myself with the fact that I have well fed snails? What do I do while I wait for the birds to get off their feathered behinds and do their job eating the insects that I’m restraining myself from spraying? When do these natural ecosystems kick in?
Before we begin, its important that you ask yourself these very important questions!
The first step is to figure out whats behind the carnage or the ailing plant.
Plants are usually pretty good at fending the insects or diseases off themselves. A healthy, well looked after plant is not likely to be affected by insects or diseases. So firstly, make sure that your plant is getting the optimum combination of the 3 essentials – light-water-food.
Once you’re sure you’re not under or overwatering, or you know the plant is in the right place, and you’ve fed it with a good nutrient-rich compost then maybe its time to get off defence and plan your attack.
So, before reaching for the pesticide spray, take a look at these natural remedies for getting rid of pests and diseases. These are the most common problems that I have seen throughout the years, and the home made remedies that go a long way to getting rid of them:
These are tiny green or light brown insects often clustered around new buds. They suck the sap out of the plants, and can spread plant viruses. Often the most obvious sign of aphids is an abundance of ants, and a black sooty mould on the leaves and ground. This ants are actually milking the aphids which secrete a sugary substance which is what forms the black mould. (Soap Spray, Garlic Chilli Spray and Horticultural Oil).
Caterpillars vary in size and description, and love all kinds of soft leaves and juicy plants. They are often found hiding on the under sides of leaves. Evidence of their presence is usually their little black poos on leaves and around the base of plants (Garlic Chilli Spray and Horticultural Oil).
Mealy bugs are small cotton woolly insects that hide along stems and midribs, and similar to aphids, encourage ants with their sugary sap that they produce. Black sooty mould is often present. (Soap Spray, Garlic Chilli Spray and Horticultural Oil).
Red Spider Mite
These tiny almost microscopic little spiders are more easily spotted by their tiny cobwebs on the underside of yellowing leaves. They thrive in dry windless environments like indoors or sheltered spots near buildings. (Water, Wind, Soap Spray, Garlic Chilli Spray and Horticultural Oil).
Often look like tiny waxy bumps along the midrib of leaves or around soft stems of plants, they can be black, brown or white, and also encourage ants to feed off the sticky sugary substance that they produce. (Soap Spray, Garlic Chilli Spray and Horticultural Oil).
These are extremely tiny little “flies’ that are actually more similar to aphids. They congregate in their thousands often on the underside of new leaves and fly away quickly when disturbed. It is best to do follow up sprays every 2-3 days. (Soap Spray, Garlic Chilli Spray and Horticultural Oil).
Snails and Slugs
Often found hiding in the cool undersides of leaves or rocks. You can often spot their silvery trails around the plant or soil beneath. (Beer, Grapefruit halves, Egg shells)
Pest Control Solutions:
Soap Spray – Dissolve 3 teaspoons of liquid soap or washing detergent in 2 cups of water into a spray bottle and use it to control aphids on roses, citrus and other plants. The soap removes the aphids waxy coating and dries them out. Also good for mealy bugs, ants and whiteflies.
Garlic-chilli spray – Chop and boil 4 onions, 4 hot chillis and 2 garlic cloves in 2 litres of water for about 15 minutes. Let the liquid cool overnight, then strain into a jar and add 2 tablespoons of liquid soap. To spray, mix 10ml of your concentrate in 1 litre of water in a bottle and use to control aphids, caterpillars, whitefly, and other pests.
Horticultural oil – Use 2 cups of vegetable oil and 1/2 cup of liquid soap. Shake together in a jar, where the mixture will turn a milky colour. Add 2 tablespoons of this concentrate to a litre of water and spray. This controls most insect pests, including scale, aphids, white fly, leaf miner, mealy bug and mites.
Hollowed out orange or grapefruit halves placed upside down overnight – These attract snails and slugs inside them. These can then be collected from the garden and thrown away.
Glass of beer – Snails and slugs are a sucker for a good glass of beer, into which they crawl in and drown. At least they die happy?
Crushed-up egg shells spread around the base of plants deters snails and slugs. They are too sharp for the soft undersides of these creatures.
Other Home Remedies:
Baking Soda is great as a preventative measure against powdery mildew on plants. Mix 1 tablespoon of baking soda, 1/2 teaspoon of liquid soap and 3 litres of water. It can burn the leaves of some plants so water plants well before use and don’t apply in full sun. Try and get the under side of the leaves too. In very humid conditions, Powdery Mildew can also be prevented by watering the soil rather than leaves.
Vinegar, or Boiling Hot water can be poured into paving to kill plants between bricks or pavers.
Milk Spray Fungicide – Also works best as a preventative measure or in the early stages. Mix 50ml milk into 450ml water and spray onto the leaves. Re-apply every time it rains. Not effective on badly affected plants.