Companion planting involves interspersing plants that naturally repel pests due to their pungent aroma like lemongrass with those that naturally attract pests like chilli and brinjal. Photos: Kuan Chee Choun

A thriving garden often attracts a fair share of bugs, insects and other pests.

But different pests require different ways of dealing with them, says Petaling Jaya-based avid home gardener Kuan Chee Choun.

Mealybugs, a very common pest that attacks edible plants, are tiny white furry insects that can come in the hundreds if you don’t control them.

If you happen to see the bugs, physically remove them. Once you do that, their numbers will not expand.

If you do need some pesticides, there are many natural concoctions you can easily make at home.

1. Soap-based solution

A simple pesticide you can make for plants is to mix a bit of detergent with water and spray it onto the plant.

“But you have to be very diligent about the spraying as you need to spray directly at the insects.

“A lot of people also add neem oil into the mixture for its anti-microbial properties. This mixture will take care of almost all types of bugs in a regular home garden, ” says Kuan.

2. Milk-based solution

“These are good for spider mites, which look like tiny specs of dust. Because they are so hard to see, it’s hard to physically remove them and they can cause your plants to become spotty or yellow, ” says Kuan, adding that spider mites love to attack bunga telang and legumes.

For this pest, mix about five tablespoons of milk (powdered or liquid) with 500ml water and a teaspoonful of flour. Spray your plant from top to bottom. That will kill the spider mites.

“But overall, healthy plants naturally resist bugs. Only when plants get weak – because of drought or too much rain – is when the bugs will come.

“So I concentrate more on the fertility of the soil to keep plants healthy. Healthy plants naturally repel pests, ” explains Kuan.

Kuan spraying a milk-and-flour-based pesticide to manage spider mites on his butterfly pea vines.

3. Companion planting

Another method is to practise companion planting. “There are certain plants that are naturally pest-resistant, like lemongrass and tarragon due to their pungent aroma.

“Intersperse these plants with other plants that are very susceptible to pests, like chilli or brinjal. It’s a very effective method, ” says Kuan.

4. Wood vinegar

A by-product of the charcoal-making process, wood vinegar is derived by distilling the smoke and gas that is released when wood is burnt in a kiln.

To make the pesticide, dilute about 2% of the wood vinegar with 98% water and use it as a spray.

“Bugs are very sensitive to ambient conditions. If there is a change in the acidity of the environment by spraying a light coat of the vinegar, that will change the microbial population of your plant, ” says Kuan.

5. Photosynthetic bacteria

“In Thailand, many people grow things successfully and what they use is photosynthetic bacteria (PSB), ” says Kuan, of the purple concoction.

The mixture is made with egg white, a litre of water, some MSG (monosodium glutamate) and fish sauce, which is then put under the sun.

“There is a class of bacteria that actually survives in the sun, which is the PSB.

“Use it to spray the leaves and soil. It will displace fungus and make a very good pesticide.”