and Integrated Pest Management - part - usaid

PFST MANAGIMIIOI" Oil. PALM IN INDONESIA
207
the War. Based on the study that he conducted in Indonesia in 1980, Desmier de
Chenon (1982) found many natural enemies of LECs. Some of them are shown
inAppendix 1. Many of them are the same spccies that were found bef6re World
War II. This means that despite destruction of many plantations during World
War II and several years after that, and the excessive use of broad-spectrum
insecticides, they survived, although they are now unable to control the pests.
Conservation and augmentation, therefore, are the natural ways to protect these
natural enemies. Mangoend iardjo (1986) reported that many natural enemies of
estate crop pests were able to establish themselves and develop after conservation
and augmentation.
Different species of LECs are often attacked by different natural enemies, as
shown in the case of 1)arnatrima and Setora nitens. Desmier de Chenon (1983)
reported that up to 30% of Darna trima larvae were destroyed by Apaniteles sp.,
Darna'smost effective parasitoid. When the caterpillars reach middle instar, they
are attacked mostly by Forniciasp. and by Plaiplccirus orthocraspedae. A
lachnid Cltcu'nxorista ai'anaattacks tIle last inslar and emerges from tie cocoon.
Predahtors Svcaum., dichotoinus (Reduviidae) and Cantheconidea furcellata
(Pcntatoniidae) also destroy the caterpillars. A virus disease is also reported
effective against tie caterpillars.
Desmier de Chenon (1983) also reported parasitization of Setora nitens. The
eggs are parasitized1by Tricogralninatoideanana. An eulophid and Platyplectrus
orthocraspedaepalrasitize the first instar larvae. Forniciasp. :%.eier with Rogas
and Apancles sp. altack the m1ddle instars. Spinariaspinator(Ichneumonidac),
the most frequent parasitoid, attacks the fourth instar onward. Chaetexorisic
javana is the most effective larval-pupal parasitoid.
Development of these nat ural encemies is encouraged if the adults can feed on
the nectar of flowers. Therefore, the presence of cover crops in oil palm
plantations is important as a source of food for tile adults. Some important
parasitoids take refuge or rest in the natural vegetation such as some broad-leaved
weeds or ferns. Syed and Shah (1976) reported that an outbreak of
Crenaiopsyche pendula and a small explosion of Thosea bisura occurred in
Sabah in 1972, and were traced to intensive use of the herbicide that killed
Euphoriageniculataand E. prunifoliutn, weeds frequented by natural enemies of
the pests. A fungus, Cordyseps sp., that attacks the pupae of Setora nitens and
77Tosea asigna in the ground will develop better when humidity in the soil is
maintained.
When natural enemies are able to keep pest populations clown, less
intervention by man is necessary, so less insecticide is needed. There is no
doubt that excessive use of insecticides is harmful to natural enemies. Therefore,
insecticides should be used judiciously and efficiently, and one of the immedite
objectives is to reduce in;ecticide consumption.
,JUDICIOUS USE OF INSECTICII)ES
Despite their weaknesses and the bitter experience they gave to oil palm
owners, particularly in the 1960s, insecticides remain important weapois in the
control of oil palm pests. The circumstances in the 1960s were such that it was