Natural 'Enemies' most welcome ! | Daily News

Natural 'Enemies' most welcome !

Your Home Garden is most efficient and makes sense when it is 100% natural. It is imperative that it remains natural and this means not using artificial chemicals because that defeats the whole purpose of having a Home Garden! Last week Green Thumbs touched on identifying pests and diseases. In today’s Green Thumbs we speak of taking battle to the enemy! We speak to Agriculture Instructor, Agriculture Instructors Office, Homagama, Indika Gunasena and Part- time Landscape Gardener, Roshani Jayatilaka on using natural methods to fight Pests and Diseases.

Agriculture Instructor, Agriculture Instructors Office, Homagama, Indika Gunasena pointed out that in a Home Garden we want fresh and natural produce. In other words’ fruits and vegetables that are uncontaminated. Gunasena stated that the nutritional value in a home garden is at its best when artificial chemicals are not used.

“What pests and diseases do is they inflict damage in such a way that you are unable to obtain the harvest you had planned for, disrupting your lifestyle. We can categorize pests and diseases under three categories – Weeds, micro-organisms (Fungus, Bacteria and Virus) and insects. From these categories, some or all are in our home garden,” said Gunasena.

Fresh harvest

In a Home Garden Weedicides, Pesticides and Insecticides are not used. If these are used, then that defeats the whole purpose of a Home Garden since we want the yield to be fresh, healthy and nutritious, so it has to be 100% natural.

“We can use a method called Integrated Pest Management (IPM) is an ecosystem-based strategy that focuses on long-term prevention of pests or their damage through a combination of techniques such as biological control, habitat manipulation, modification of cultural practices, and use of resistant varieties. Pesticides are used only after monitoring indicates they are needed according to established guidelines, and treatments are made with the goal of removing only the target organism. Pest control materials are selected and applied in a manner that minimizes risks to human health, beneficial and non-target organisms, and the environment,” explained Gunasena.

He went onto explain that when it comes to weeds, without using Weedicides we use our hand to remove the weeds. We prevent them from falling to the ground because if they fall to the ground they grow again. That is how we control weeds and how we create the environment we want and need. Other ways of controlling weeds is applying a mulch (material such as decaying leaves, bark, or compost spread around or over a plant to enrich or insulate the soil) to cover the ground.

When it comes to micro-organisms such as Fungus, Bacteria and Virus, we need to remove the infected leaves with our own hands and separate them. If we see something that is not right with the plant, we remove those parts and burn them. We do not allow them to fall to the ground and remain there because then the virus has the opportunity again to contaminate.

“Another method is sterilizing the soil. We apply straw over the soil and burn it. Then the soil becomes sterilized because of the intense heat. We can even use sunlight to sterilize the soil. What we do is we turn the soil over and because of the heat it sterilizes. That takes care of those nasty micro-organisms,” pointed out Gunasena.

He also added that when bringing plant material into your home garden, you need to make sure it is healthy. Otherwise you are bringing the enemy into your garden and ruining your chances of having a self-sufficient year- long home garden. Your home garden is not so huge. You can use discarded clothes to form a barrier between your home garden and the external environment. Then that will prevent pests coming into the garden. Then you create a controlled environment. This is a low cost method.


Also all these abnormal parts of plants that we detect can be put into a bag and kept aside. The life circle of a home garden pest is a very short period around 10 days. Around 10 days they mature and lay their eggs. So they need to be controlled.

Also we can use natural herbicides and insecticides. We do not use synthetic products because then it is a failed home garden. We need to keep things as natural as possible. Some of them are – Neem Extracts, Tobacco Extracts, Soap, Cow Dung, Papaya Leaf Extraction, Chili Extracts and Garlic Extracts. This how to destroy these pests and diseases. These extracts have a chemical that repels these pests and diseases. All of this is 100% natural. Pepper Spray is another method. If you take Mealybugs, a method we use is spraying water at high pressure.

“So without artificial chemicals is the way to go. Using natural methods is the best way to make sure your produce is natural, safe and healthy. There are three types of controls. One is Biological control. It is the use of natural enemies—predators, parasites, pathogens, and competitors. They are used to control pests and their damage. Invertebrates, plant pathogens, nematodes, weeds, and vertebrates have many natural enemies.

The second is Cultural controls. Cultural controls are practices that reduce pest establishment, reproduction, dispersal, and survival. For example, changing irrigation practices can reduce pest problems, since too much water can increase root disease and weeds.

The third is Mechanical and physical controls. Mechanical and physical controls kill a pest directly, block pests out, or make the environment unsuitable for it. Traps for rodents are examples of mechanical control. Physical controls include mulches for weed management, steam sterilization of the soil for disease management, or barriers such as screens to keep birds or insects out,” explained Gunasena.


Part- time Landscape Gardener, Roshani Jayatilaka who has been in the gardening business for a very long time, also stated that commercial pesticides are harmful to humans as well as they pollute the environment.

“In Sri Lanka there are traditional methods like using natural products such as the oil you get from Kohomba seeds, spraying tobacco infused water, sprinkling wood ash and planting trees that emit an odor that prevents pests. There is also the commercially made liquid neem as well in India. It is not harmful to humans and does not pollute the environment. Another method is growing plants in between each other, so the smell will not attract pests” said Jayatilaka. She went on to point out that there are a variety of natural pesticides that can come from your kitchen. These would include – Salt Spray which is one of the best and most natural way. There is also onion and garlic spray. All you need to do to make this is, taking about one clove of garlic and one medium sized onion and adding some water to them. You can also use Eucalyptus Oil and the Chrysanthemum flower.

“As you know there are many types of pests and there are also plants that can be used to prevent them. If you take Aphids, they can be prevented by using chives, coriander and nasturtium. If you take Ants, you can use tansy. For the Asparagus Beetle I suggest pot marigold. The bean beetle can be prevented by using marigold, nasturtium and rosemary. For the Cabbage moth it would be hyssop, mint and oregano, rosemary, sage, southernwood, tansy, thyme. Lastly for the Carrot Fly, I would use rosemary and sage,” explained Jayatilaka.

If you take Neem oil, it is a naturally occurring pesticide found in seeds from the neem tree. “It is yellow to brown, has a bitter taste and a garlic/sulfur smell. It has been used for hundreds of years to control pests and diseases,” stated Jayatilaka.