Going back to nature for crop protection
By Faridah Begum
GOING back to nature for lessons in crop protection has long been Kumpulan Guthrie Berhad’s policy.
Its Chemara research station at Jalan Sungai Ujong in Seremban is intensifying the use of animals, insects and "natural insecticides" in the fight against pests, weeds and disease.
It is here that Guthrie’s Integrated Pest Management (IPM) programme involving the application of ecological principles in the control of pests and diseases, is evolved.
"IPM is achieved through judicious use of pesticides, biological control, prudent application techniques and agricultural practices culturally," said the research station’s controller (research and development) Dr Chan Kook Weng.
Among the methods being researched before introduction to Guthrie plantations and estates is the use of cocoa black ants to control mind bugs. The mirid bug (Helopeltis theobromae), Dr Chan said, attacks cocoa plants and fruits, thereby resulting in losses.
Although pesticides are effective means of controlling the mirid bug, it was found that the cocoa black ant (Dolichoderus thoracicus), together with its associate the mealybug (Cataenococcus hispidus), repel the bug naturally.
"This helps us reap uninjured fruits and trees at minimum cost and frees us from our dependency on pesticides for the control of the pests."
Weeds have also been successfully controlled through the use of insects. Four weeds have been identified which can be controlled with insect biocontrol agents. They are:
• cordia curassavica by the insect metrogaleruca obscura;
• mikania micrantha by the liothrips mikaniae;
• salvinia molesta by the cyrtobagous salviniae; and
• eichhornia crassipes by the neochetina bruchi and the N. eichhorniae insects.
Use of insects has meant cost savings for the plantations in terms of herbicides and labour for spraying and removal of weeds.
Using natural insecticide like bacterial spores (i.e. Bacillus thuringiensis), which is injected into the tree trunk where bagworms —caterpillars of small moths -feed on oil palm fronds is yet another crop protection method practised in Guthrie plantations.
Whie this method is selective of only areas where the attack is deteched, in cases of outbreaks affecting large areas, aerial spraying is done for quick and timely control.
"Here, only time-tested short-residual and selected insecticides are sprayed; to minimise ecological disruption," he said, adding that the method employed here would cause the death of many caterpillars but were absolutely safe to othernontarget animals.
Rats, a common feature in oil palm plantations have been controlled by barn owls for some years now.
With more than 1,900 nest boxes in Guthrie plantations (about 10,000 birds), the barn owls thrive well and these predators of rats also help check economic losses.
Using barn owls, the man agement has seen less damage done on fruit bunches, especially on taller palms.
Senior manager, crop protection Liau Siau Suan, based in Chemara, adds that the loss by detached fruits is a great risk.
Environment-friendly ways that enhance productivity
THE Guthrie Chemara research station is also actively involved in finding environment-friendly practices to enhance productivity in the plantations.
Its controller (R&D) Dr Chan Kook Weng said practices like open-burning were being phased out.
Instead, Guthrie has found that zero-burning helps reduce excess production of carbon dioxide while maintaining a cool temperature.
Instead of burning rubber logs and branches they allowed them to decay and found less soil erosion and reduced silting in streams and waterways. This prevents massive flooding.
Decay of these rubber logs too enriches the soil with organic matter, amking it more fertile.
Silt pits have also been created to reduce surface run-off during rain. These pits also enhance plant growth as it helps conserve rainwater.
Timber from rubber trees is plentiful and plantations have utilised them for furniture making.
Instead of just planting cover crops to prevent soil erosion and quick cash supplements, plantations have also begun cultivating rattan.
"Planted under mature rubber trees, this helps provide a better supply of rattan. Besides this reduces the rampant harvesting of rattan in the jungle, causing the extinction of some species," said Chan.
The other two environment-friendly plants planted at Guthrie plantations are Jojoba ( Simmondsia chinensis ), an evergreen shrub that produces liquid wax in its seeds, similar to that of the sperm whale oil; and Kenaf ( hibiscus cannabinus ), a good substitute for jute.
Kenaf is also found to be good paper pulp, with characteristics comparable with or even superior to that of hardwood and softwood pulps for papermaking.
According to Chan, they have found it a good ingredient to add to recycled paper. By-products formulated from palm oil are a special organic fertiliser made from palm oil mill solids and sheep dung, palm trunk for furniture and sheep grazing as an alternative to herbicide spraying.
Disposing of empty fruit bunches used to lead to unsightly heaps. This been rectified by making it natural fertiliser for plants.
Some of the commercial and environment-friendly uses are converting of empty fruit bunches into organic mulching, bunch ash as potassic fertiliser, palm oil mill solids as nursery potting mix and organic fertiliser, cyclone fibre as solid boiler fuel and mulch, and refined bowl trap sludge as phosphatic fertiliser.
For the future, the Chemara research station, Chan said, would look into the planting of other forest plant species that are fast growing and frond spreading in an oil palm plantation.
Source : New Straits Times January 1993
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