Sunflowers have been found to be effective in controlling pests and also host beneficial insects. Photos: 123rf.com
Gardening offers relaxation, mental rejuvenation, and if vegetables or fruits are planted, it is a rewarding activity to provide nutritious food for you and your family. Maintaining a healthy garden often involves contending with pests.
But instead of using harmful pesticides, integrating beneficial plants into the garden is a better option to naturally deter harmful insects.
These beneficial plants could not only assist in controlling pests but also add colour to the garden. But what are the plants that should be planted and that are easy to care for?
This decision may seem daunting, so let me recommend several common and easy-to-care plants.
One common flower is the marigold (Tagetes erecta), an annual plant that easily germinates from seeds, which comes in various colours. This plant emits a strong odour that can deter insects and bugs. It also repels root-knot nematodes (Meloidogyne spp.), as their roots are known to secrete chemicals that repel this microscopic worm-like pest.
The marigold further attracts the Lynx spider (Oxyopes javanus), which preys on mirid bugs, and Tachinid flies, a parasitic fly that controls caterpillars and beetle larvae pests.
Marigold emits a strong odour that can deter insects and bugs.
Lantana camara is another flowering plant that adds splashes of colour to the garden. However, it is mildly toxic to both children and animals.
Studies have shown that the smell of this plant can be useful for repelling mosquitoes. The extract of its leaves could repel the activities of insects such as Sitophilus zeamais, a rice weevil.
Beyond its repellant qualities, Lantana camara is also a magnet for pollinators. Bees, butterflies, and hummingbirds, drawn by the plant’s nectar, become regular visitors, enhancing the garden’s ecological balance.
Sunflower or Helianthus spp., comprising many species of annual and perennial plants, can be used as hedges or for wind control in gardens. This crop grows more easily and faster than weeds do.
Sunflowers have been found to be effective in controlling pests, such as leaf miner flies (Liriomyza), mosquito bugs (Helopeltis), thrips, and aphids. In addition, it hosts beneficial insects, such as Xanthopimpla sp. (an important parasitoid), Mentadak (Mantodea: Mantidae), and the robber fly.
Jasmine plant is a good trap crop for aphids.
Other plants that are common in Malaysia and can attract benficial insects include Roselle (Hibiscus sabdariffa), Turnera spp., and Cosmos spp. (Ulam raja), Arachis pintoi (leguminose ground cover), and senduduk (Melastoma malabathricum). These plants not only attract beneficial insects but also function as sanctuaries.
Also consider the benefits of companion planting. This time-tested method involves growing different crops close to one another to reap their mutual advantages. For example, tomatoes paired with basil offer a symbiotic relationship: basil repels specific pests targeting tomatoes, whereas tomatoes enrich the flavour of basil.
To enhance the garden’s resilience against pests, plant selection should be diversified.
Introducing a range of plants not only confuses pests and prevents them from locating their favourite hosts but also naturally diminishes their numbers.
In addition, the trap-cropping strategy can be effective. Jasmine plants are effective trap crops for aphids. Nevertheless, to manage the aphid population within these trap crops, the utilisation of natural pesticides is recommended.
The neem solution, for instance, is a proven homemade remedy that can be applied to Jasmine to eliminate aphids.
For those serious about embracing this natural approach, it is prudent to plant these beneficial species before their main garden plants.
By doing so, they can help establish a harmonious garden ecosystem and bolster populations of beneficial insects.
However, for those who have already embarked on their gardening journey, it is still not too late. The introduction of these plants at any stage would be advantageous.
It is also essential to maintain the steady presence of nectar-producing flora to ensure the continued support of our insect allies.
Assoc Prof Dr Norida Mazlan has 20 years of experience in plant protection. She also heads the Department of Plant Protection, Faculty of Agriculture, Universiti Putra Malaysia. The views expressed here are entirely the writer’s own.
