Category Archives: 1996 Vol 8 No 1

Isolation and amplification baculovirus as a biocontrol agent for bagworms and nettle caterpillars of oil palm

Outbreaks of bagworms (Lepidoptera: Psychidae) and nettle caterpillars (Lepidoptera: Limacodidae) in oil palm occasionally affects some estates in Malaysia. Control involves mainly the use of systemic chemicals such as monocrotophos and methamidophos and the spraying of selective narrow spectrum insecticide such as triclorfon. Chemical insecticides pose several potential hazards such residual problem, insect pest resistance to chemicals and increased frequency of pest outbreaks. In the 1991 national biological control conference, integration of selective chemicals with biological control was recommended as a strategy towards non-polluting agriculture in Malaysia. Use of baculovirus (BV) as a biological control agent supports this recommendation. The objective of this study is to report the progress made in collection, isolation and amplification BV for the control of some oil palm insect pests.

Collections of 62,000 larvae of Metisa plana, Wlk (Lepidoptera: PSychidae) and 1000 other pests were made in 1992-1995 from 20 estates in Selangor, Johor, Negeri Sembilan, Pahang, Sabah and Perak. The larvae were dissected, treated and examined for BV infection, particularly the subgroup A and B. The results indicated that nucleopolyhedrosis virus (NPV) was detected in M. plana, but the degree of infection was tertiary, meaning that it did not successfully infect the host. Granulosis viruses (GV) were detected more frequently than the NPV. Detection of BV was enhanced in stressed and newly dead larvae.

To date, Mahasena corbetti NPV (McNPV), Darna trima GV (DtGV), Spodoptera litura NPV (S1NPV), Mamestra brassicae NPV (MbNPV), Agrotis segetum NPV (AsNPV), A.segetum GV (AsGV), Autographa californica NPV (AcNPV) (L1, 210,449) and Panolis flammae NPV (PfNPV) have been purified. Mass production of BV for field experiment has been by in vivo amplification of these viruses in an alternative host, S. litura was carried out. The amplified viruses and cross-infectivity studies against oil palm insect pests.

Histopathology of Metisa plana (Lepidoptera:Psychidae) infected with Beauveria bassiana Deuteromycotina:Hyphomycetes)

Fourth larval instars of Metisa plana Walker were sprayed with conidial suspensions of Beauveria bassiana(Balsamo) Vuillemin containing 6.25 x 10-6 conidial/ml. The mode of fungal infection was determined histologically. At 48 hours after inoculation, fungal hyphae penetrated the integument inside the trachea and via the nuclei of epidermal cells. Fungal hyphae infiltrated the fat bodies underlying the integument. At 72 hours after inoculation, the fat tissues were damaged by progressive colonization with hyphae. Subsequently, the hyphae invaded the muscle tissues, neural tissues, germ cavities, Malpighian tubules, gut musculature and epithelial cells, and finally colonized the gut lumen. Between 96 and 120 hours post inoculation, all internal organs of the bagworm were heavily colonized with hyphae, and the infected bagworms were already dead. Twenty-four hours after death, whitish mycelia began to emerge from the cuticle of the bagworm cadavers.

Refining of red palm oil

A process has been developed for the refining of crude palm oil (CPO) to produce Red Palm Oil (RPO) without destroying the carotenes. It involves a pretreatment of CPO followed by deacidification and deodorization using molecular distillation. The RPO produced has less than 0.1% of free fatty acid (FFA) and retains more than 80% of the original carotenes and vitamin E originally present in the CPO. The quality of RPO is similar to that of ny refined, bleached and deodorized palm oil in terms of FFA and peroxide value (PV). The carotene profile of RPO showed that most of the carotenes were retained. The process has been commercialized and the product is expected to be in the market soon.

Fluorescence in situ hybridization of rRNA probe to Elaeis guineensis (Tenera) chromosomes

Fluorescence in situ hybridization (FISH) was performed on Elaeis guineensis (tenera) chromosomes using the highly repetitive ribosomal ribonucleic acid (rRNA) gene probe, pBG 35, from flax. FISH of pBG 35 on interphase cells showed two hybridization sites, thereby indicating two nucleoli, while FISH on metaphase chromosome spread showed the presence of four nucleolar organizer regions (NORs).

Ultrasonic studies of palm oil and other vegetable oils

This paper reports the propagation and the attenuation of sound waves in crude palm oil (CPO), refined bleached deodorized (RBD) palm oil, palm olein and some other vegetable oils; coconut oils, corn oil and soyabean oil. The ultrasonic pulse echo overlapped technique has been employed to obtain the ultrasonic properties of the oils from room temperature up to 90°C. The velocity of sound in vegetable oil products decreases linearly with temperature, while their ultrasonic attenuation decreases exponentially with temperature. The ultrasonic properties of the oils are very dependent on their viscosity, density and molecular structure. The ultrasonic wave velocity and attenuation coefficient can be used as a basic tool to identify Malaysian palm oil.

Isoenzyme variation of Zairean oil palm (Elaeis guineensis Jacq.) germplasm collection

Genetic variation was studied in a Zairean oil palm germplasm collection by employing native polyacrylamide gel electrophoresis of isoenzymes. Three isoenzymes extracted from leaves, namely superoxide dismutase (SOD), peroxidase (PRX) and glutamate dehydrogenase (GDH) were investigated. Polymorphism was detected in SOD and PRX systems but there was no genetic variation in GDH system. Polymorphic indices obtained from SOD and PRX systems revealed that the degree of polymorphism increased from the family to the ecotype level. This study also showed that the degree of polymorphism is influenced climatically and geographically.