and Integrated Pest Management - part - usaid

PEST MANAGEMENT ON OIL PALM IN MALAYSIA
S. S. Liau
Manager, Plant Protection
Guthrie Research Cheinara, Jln. Sungai Ujong
70990 Seremban, Negri Sembilan, Malaysia
The area under oil palm in Malaysia hois dramatically increased in recent
years, and it is estimated that at the end of 1986, there were about 1,458,100 ha.
During the rapid expansion of the industry in the late 1950s and early 1960s, the
oil palm was plagued with indigenous leaf-eating caterpillars. Spraying with
broad-spectrum and persistcnt insecticides resulted in further outbreaks and
resurgences of these pests. Local entomolosists were prompted to advocate
usipg principles of Integrated Pest Management (IPM) on oil palm, and since the
mid-1960s, IPM has become well accepted in the Malaysian oil palm industry
and has helped to reduce the seriousness of pest outbreaks.
MAIN PEST PROBLEMS
'fhe main insect pesls on the oil palm are the defoliating caterpillars,
particularly the three major species of bagwormn (Psychidae), and about five
major species of nettle caterpillars (Limacodidac), which have caused extensive
outbreaks covering large areas of 2000 ha or more. The other defoliators of
lesser importance are two hairy-caterpillars (Lymantridac), three cockchafers
(Mclolonthidae and Rutellidac), and a grasshopper (Acrididae) species. Another
insect pest which has become more important in recent years, especially in
paln-to-palm rcp!ants, is the rhinoceros beetle, Orycies rhinoceros (Dynas.inmae).
Economic losses caused by these defoliators have been estimated by Wood et
al. (1972), through a damage simulation trial, to be as high as 40-50% of the
crop over a period of two years after a single defoliation of 100%. At present
prices, this represents a loss of USS400-S650 per ha. Defoliation in nmature
pahls showed similar responses, but to a lesser degree, with 12-36% loss in
yield (Chcmara, unpublished data).
However, all these are only occasional pests. Usually, they are present in
extremely low numbers, obviously being kept well under control by natural
factors. Most of the caterpillar pests have a great numbcr of attendant parasitoids
and predators, which have been rccorded during outbreaks (Syed et al. 1974,
Tiong 1982). In most cases, it is yet uncertain how these natural enemies
operate, nor is it known which species exert the most effective regulatory
pressures on the pest concerned, especially in non-outbreak situations.
The only chronic pests in Malaysian oil p.flm plantations are rats. In the
absence of effective control measures, rat populations can potentially build up to
economically damaging levels, causing losses of about USS70 per ha per