Identification of Cordyceps javanica and its effectiveness in Controlling Bagworm, Pteroma pendula JOANNIS (LEPIDOPTERA: PSYCHIDAE)

The application of biological control agents as one of the control methods to suppress the infestation of bagworm in Malaysia has developed steadily with the inundation release of formulated entomopathogenic microbes to the outbreak area. In this study, we isolated and identified the entomopathogenic fungi (EPF) from the dead larvae of the bagworm, Pteroma pendula. Mycoses dead bodies of P. pendula were collected from two locations in Kemayan, Pahang, Malaysia. Morphological characterization of EPF was carried out by observing the macroscopic and microscopic growth on Potato Dextrose Agar (PDA) plates using a compound microscope. It was observed that white colonies on PDA changed into purple or pink shades after sporulation. The colony is slow-growing with floccose mycelium, which produces conidiophores with three to four phialides. The conidia were cylindrical to fusiform, smoothwalled and formed in chains on mononematous conidiophores. All the isolates were observed to be similar to Cordyceps fumosorosea features. Molecular identification using universal primer (ITS4 and ITS5) has identified that the isolates were Cordyceps javanica and Parahevansia koratensis. Bioassays of identified isolates were carried out against the second instar larvae of Pteroma pendula showed that C. javanica isolates BSB01 achieved LT50 - 6.76 days and recorded the shortest lethal time compared to the other isolates

Formulation and laboratory efficacy of isaria fumosorosea against bagworms (Metisa plana walker and Pteroma pendula joannis) (lepidoptera: psychidae)

Relying solely on chemical insecticides for bagworm control in oil palm plantation could lead to many consequences to the ecosystem, environment and human. Thus, developing mycoinsecticide that able to control this pest could be the alternative to reduce chemical insecticides dependence. Entomopathogenic fungi might fulfil their potential with suitable choice of formulation and stable throughout the application and storage period either in biological, chemical, or physical aspect. Wettable powder is the formulation to be developed due to its easy and cheap production procedure. In this study, three fungi isolated from the infected Pteroma pendula collected from United Malacca Berhad (UMB) plantations in Pahang and Negeri Sembilan were found to be Isaria fumosorosea based on the morphological observations. Those three isolates were identified using molecular identification procedure along with six isolates obtained from Forest Entomology Laboratory, Faculty of Forestry Universiti Putra Malaysia (UPM). Six of the isolates were I.fumosorosea where isolate BSB01 isolated of infected bagworms from UMB Plantation in Kemayan, Pahang was the most virulent isolates against P.pendula. This isolate was then mass produced and formulated with surfactants and filler. The compatibility of dispersants and wetting agents with this isolate was determined earlier before being used in wettable powder formulation. Screening the surfactants against I.fumosorosea BSB01 conidia viability and fungal growth were conducted on the isolate, aerial conidia and submerged propagules. Surfactants found to be qualified were TERSPERSE® 2105, TERSPERSE® 2700, ELTESOL® SC, ELTESOL® SX, sodium naphthalenesulfonate, sodium lignosulfonate, sodium polyacrylates, and SIPERNAT® 22S. Among those qualified surfactants, two of them are wetting agents (ELTESOL® SC and ELTESOL® SX). Concentration of surfactant affects the conidia viability at 10% or higher. A surfactant system consisted of two dispersants and a wetting agent were prepared using pseudoternary phase diagram. Stable regions in each surfactant system were combined to find the mutual stable region. The single point was selected from the mutual stable region with the limit of wetting agents fixed at 15%. The stable region showed satisfying physical stability against kaolin. The best point was found to be at the ratio of 52:33:15 (Dispersant 1:Dispersant 2:Wetting agents). The surfactant ratio was then characterised with the presence of fungal aerial conidia and fungal submerged propagules. Submerged fungal propagules formulations showed better physical stability compared to the aerial conidia formulation. Although all formulations showed a steep decline of active colony counting from 9.0 × 108 to 1.0 × 108 cfu mL-1 within the first three days storage, these formulations maintained this viability until 90 days. Biological efficacy of the formulated submerged propagules were determined where all formulations showed no significant difference of LT50 values when compared with unformulated against Metisa plana and P.pendula

Population abundance of oil palm pollinating weevil, Elaeidobius kamerunicus faust and its relation to fruit set formation in mineral and peat soil areas in Peninsular Malaysia

The oil palm pollinating weevil, Elaeidobius kamerunicus, plays a vital role in the oil palm fruit formation process. An insufficient pollinator population may cause poor fruit set formation, resulting in a high number of parthenocarpic fruitlets and malformed fruit bunches. This study examines the population level of E. kamerunicus at two sites in Peninsular Malaysia and its relation to the fruit set formation. Each site represented different soil types, viz, mineral and peat soil. Preliminary results of the study showed that both sites had high adult weevil population density, averaging at 68662.87/hectare and 89270.93/hectare for peat soil and mineral soil, respectively. The average sex ratio of inflorescences in peat soil area (58.09%) was significantly higher than those at mineral soil area (45.01%, F = 6.75, P = 0.016). The average fruit set percentage in both study areas was satisfactory (more than 60%). The average fruit set in mineral soil area (83.08%) was significantly better than those recorded at the peat soil area (69.47%, F = 4.42, P < 0.05). Even though there are differences in terms of the population level of the pollinator, the fruit set formation in both areas is still satisfactory

Impact of Elaeidobius kamerunicus faust introduction on oil palm fruit formation in Malaysia and factors affecting its pollination efficiency: a review

The oil palm pollinating weevil, Elaeidobius kamerunicus, has become the single most important insect pollinator of the commodity crop in Malaysia and Indonesia, 40 years after its introduction. However, in 2020, the average national oil extraction rate (OER) has decreased from 20.21% to 19.92%. The decline was attributed to the lower oil palm fruit bunch quality. This has raised concerns on the pollination efficiency of the pollinator. As such, the factors affecting the pollination efficiency of E. kamerunicus were thoroughly discussed in this review. Eight factors, which were categorised into intrinsic and extrinsic factors, were discussed in detail. Intrinsic factors discussed are the genetic make-up of E. kamerunicus and its population level. Meanwhile, factors such as planting materials, soil types, plant physiological condition, volatiles emission, diseases/predators threatening E. kamerunicus and climatic factors were discussed in the extrinsic factors. Methods for maintaining a healthy pollinator population were suggested, as well as an emphasis on future studies based on the shortlisted factors