Protecting the friendly insects in our midst
DURING a recent afternoon tea with some retired Agriculture Department staff, the question of pest control was highlighted. This was because some of them are trying their hands at growing vegetables at home. As they were more used to the management side of agriculture, some lack the practical techniques of best practices for success.
The same topic was brought up a few days later – this time during morning tea after buying groceries at the Sungai Maong Bazaar. The problem was serious, as a lady complained about how her bed of cangkuk manis was suffering from an attack of leafrollers. This was causing either a low harvest or nothing left at all.
Many of the problems I heard about seemed to be due to a lack of knowledge and experience when it came to pest control. Many of the suggestions were to resort to chemical methods.
To most of us, insects are a complete nuisance. There is an endless list of problems in our lives caused by insects. However, we rarely stop to think about why they exist in the first place. What are their roles in this world? Beneficial insects Being human, we tend to forget the significant contributions of insects to this world. Although we might realise that bees are required for pollination as well as to produce honey, or that silkworms produce silk, we rarely think about how every creature has its role in our balanced world.
When we clear land for rice planting, we only allow for rice production and cannot accept the presence of insects. So we quickly destroy them using pesticides. This actually causes pollution and damages a balanced ecosystem, where pests are actually kept in check by nature.
Pests are best managed in low numbers. Also there are many ‘friendly’ insects. Brown planthopper (Nilaparvata lugens), which causes ‘burnt’ rice, is actually food for over 200 friendly insects. However, when toxic pesticides are used, the friendly insects are also wiped out. These are the insects that are actually allies of farmers.
We have imported beneficial insects to control diamondback moths in the cabbage growing industry. The moth Plutella xylostella is a small dull looking insect that produces green caterpillars, which eat the leaves of cabbages and other vegetables.
Farmers used insecticides but still failed to control the moths because they very quickly developed a resistance to the chemicals. The problem was finally solved using a small parasitic wasp to destroy the larvae.
Insects were also used to control the weed Cordia curassavica, which damaged young coconuts and other crops. The problem was solved by importing a seed feeding wasp and leaf feeding beetle from Trinidad.
The oil palm industry has also saved billions of ringgit from having to use artificial pollination by having imported the natural pollinator Elaeidobius kamerunicus from Cameroon, West Africa. It was once thought that oil palms were wind pollinated. This was what caused the failure of the first oil palm plantation in Kanowit in the early 1940s.
The pollinators were finally imported to Malaysia in 1980, when I was still working. I had to regulate quarantine for the insects by allowing them to be tested in Miri. They were found to be useful and did not damage other crops. They have proven to be the best success in Sarawak thus far. The results were better fruit setting and a 47 per cent increase in oil production. Using insecticides judiciously In terms of pest control, we must realise the seriousness of damage caused by pests on crops. Insecticides are like fire – good servants but bad masters – especially when they are not used for the intended purposes or targets. When used discriminately, they can be effective pest control but when they dominate agricultural production, insecticides can have unwanted repercussions. This results in new problems such as pollution, insecticide resistance, and further outbreaks.
This was the case when farmers overused broad spectrum insecticides in the Cameron Highlands between the late 80s and early 90s. The free introduction of more and more potent chemicals in the war against pest outbreaks was dominated by chemical salesmen, who only wanted to increase their sales. Alternative strategies Since the 2000s, the world has begun to realise the need to redress environmental problems brought about by chemical pollution. The new strategies include alternative means of pest control, especially biological control — protecting the natural enemies of pests and introducing friendly actions for beneficial insects. The awareness was further extended by promoting safe pesticide usage and good agricultural practices, which also benefit our health as consumers.
Today we must continue to protect our environment and those friendly insects in order to preserve our very own human race on planet earth.
Do send me an email if you have questions, comments, or suggestions. Happy gardening.