and Integrated Pest Management - part - usaid

PEST MANAGEMENT ON COCOA IN MALAYSIA
C. T. Ho
Harrisons Malaysian Plantations Berhad
Prang Besar Research Station
43009 Kajang, Selangor, Malaysia
Although cocoa was introduced into Malaysia (then Malaya) as early as
1778, the crop's cultivation never really became an industry until well after the
Second World War. Various factors contributed to such a situation, inefficient
plant protection being one of them (Burkhill 1966). -lectarage under cocoa in
Malaysia has expanded dramatically since the 1940s, from just 600 bearing trees
in 1948 to 30,252 ha in 1975 and 242,000 ha in 1984 (Anon 1986), making
cocoa the third major plantation crop in the country. Improved planting
materials and agronomic practices were major contributors to the increase. It is,
however, also undeniable that plant protection and, as the various aspects of this
discipline developed, pest management on cocoa advanced in step, minimizing
setbacks to the crop's establishment, and thus adding to the success of the cocoa
industry in the country. In this paper I will outline the practices of and advances
in pest management, with particular reference to faunal pests.
MAJOR FAUNAL PESTS OF COCOA IN MALAYSIA
A great diversity of insects and other fauna are trophically associated with
cocoa. It is thus inevitable that a significant number of them would become
pests once the tree was cultivated on a large scale. Such rests are appropriately
categorized into key, occasional, and potential pests following the concept of
Smith and Reynolds (1966), and representatives of each category as experienced
in Malaysia are listed in Table 1. MacArthur and Wilson (1967) have proposed
the concept that organisms can be graded according to their population growth
strategy, which has, in turn, evolved to exploit the environment. The extremes
of the strategies for insects are the r and K selected organisms, with the inbetween
as "intermediate". Characteristics of each category are as indicated by
Heong (1981). Wood (19"/9) had aptly related the r-K continuum with Smith
and Reynolds' concept and with reference to this, it is clear that key pests of
cocoa in Malaysia (Table 1)generally adhere to the definition of being K-end or
intermediate pests that are damaging at the endemic level or are regularly pushed
to epidemic levels by cultural techniques. Conceptually, such key insects are
best controlled by regular suppression of populations to below economic levels
by use of attrition methods (e.g., selective chemicals, sterile male techniques,
biocontrol, cultural control, resistant strains).
Occasional pests are defined as those that are often found in small numbers
under natural conditions, but with the potential of outbreaks. Such insects often
belong to the intermediate to r-end of the r-K continuum. Most of the