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Whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), consists of genetically diverse species known to cause significant destruction in several crops around the world. Nymphs and adults of B. tabaci cause damage to plants during feeding, and they can act as a virus vector, thus causing significant yield loss to crops in the tropical and subtropical regions. Chemical pesticides are widely used to control B. tabaci due to their immediate action, but this approach has several drawbacks including food safety issues, insecticide resistance, environmental pollution, and the effect on non-target organisms. A biological control agent using entomopathogenic fungi (EPF) has therefore been developed as an alternative against the conventional use of chemical pesticides in an integrated pest management (IPM) system to effectively control B. tabaci. It is apparent from this review that species of hyphomycetes fungi are the most common EPF used to effectively control B. tabaci, with the second instar being the most susceptible stage of infection. Therefore, this review article focuses specifically on the control of B. tabaci with special emphasis on the use of EPF as biological control agents and their integration in IPM.

Entomopathogenic fungi (EPF) are natural enemies which affect insect population and have long been recognized as biological control agents against many insect pests. Some isolates have also been established as endophytes, benefiting their host plants without causing any symptoms or negative effects. Here we demonstrated two entomopathogenic fungal species, Isariajavanica (Frieder. & Bally) Samson & Hywel-jone 2005 and Purpureocillium lilacinum (Thom) Luangsa-ard, Hou-braken, Hywel-Jones & Samson (2011) as endophytes in tomato plants by using the seed inoculation method and examined their effect on plant growth, B . tabaci mortality, and adult emergence. Our study indicated that tomato seeds treated with a fungal suspension of I . javanica and P . lilacinum enabled their recovery from plant tissues (root, stem and leaf) up to 60 days after inoculation (DAI). Both endophytic isolates also caused significant mortality of adult B . tabaci on seedlings inoculated with, I . javanica (51.92±4.78%), and P . lilacinum (45.32±0.20%) compared to the control treatment (19.29±2.35). Adult emergence rates were significantly high in the control treatments (57.50±2.66%) compared to I . javanica (15.00±1.47%) and P . lilacinum (28.75±4.78%) treatments. This study provides evidence that endophytic isolates of I . javanica and P . lilacinum have a biocontrol potentials for used against whiteflies and could also explored as plant growth promoters.

Rhynchophorus ferrugineus (Olivier) (Coleoptera: Curculionidae) is a severe pest of palm trees worldwide. The development and feeding activities of R. ferrugineus larvae inside the trunk damage palm trees. However, the absence of noticeable infestation signs at an early stage contributes to the spread of the attack. Integrated pest management (IPM) has been introduced to control R. ferrugineus infestation by implementing various approaches and techniques. The application of chemical pesticides has shown impressive results. However, biological control should be applied as an alternative solution due to adverse environmental impacts and pest resistance issues. One example is the use of entomopathogenic nematodes (EPNs) as biological control agents, which can forage and attack targeted pests without compromising the environment and other nontarget organisms. EPNs and their symbiotic bacteria have a mutualistic interaction that can kill the host within a short period of time. Therefore, this review emphasizes the effectiveness of entomopathogenic nematodes and their symbiotic bacteria against R. ferrugineus.

Oil palm (Elaeis guineensis Jacq) is an economically important crop in South-east Asia, especially in Malaysia and Indonesia. In Malaysia, oil palm is the most profitable commodity in the agriculture sector. The future of oil palm lies in obtaining a higher yield that is aligned and directed towards achieving the Sustainable Development Goals (SDG) by 2030. Elaeidobius kamerunicus was introduced into Malaysia during the late 1980s to boost the production of oil palm fruit bunches. Almost 40 years since the introduction of E. kamerunicus, significant improvements have been witnessed in the increase of oil palm yield. Nevertheless, the current concern in the oil palm sector is regarding the decreasing of fruit set that may be affected by E. kamerunicus. The weevil population plays a crucial factor in the pollination of oil palm. Several factors had been reported to reduce the weevil population such as natural enemies, interaction with local insects, pesticides, climate and male inflorescence. These factors have been addressed in this article based on various studies conducted since the first investigation in Cameroon by Syed in 1977. The role of the pollinator in terms of its biology, behaviour and pollination mechanism is also described in this article, together with the population management of the weevils. This review article will provide a summary of the current state of Elaeidobius kamerunicus in Malaysia and other neighbouring oil palm-producing countries.

Abstract Background Three of entomopathogenic fungi, identified as Isaria javanica (Cjc-03 and Cjw-01) and Purpureocillium lilacinum (TS-01) were found naturally infecting the whiteflies, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae) on chili and tomato plants. All the isolates were identified by morphological characterization and molecular identification (ITS region amplification). The virulence of the three isolates was evaluated against nymphs of B. tabaci at three different concentrations (1 × 106, 1 × 107, and 1 × 108 conidia/ml) under laboratory conditions and on adults of B. tabaci at one conidia concentration (1 × 107 conidia/ml) under laboratory and glasshouse conditions. Results Isaria javanica showed the highest virulence against B. tabaci nymphs and adults in both laboratory and glasshouse conditions. I. javanica exhibited the highest mortality in the laboratory against B. tabaci, nymphs at the highest concentration (1 × 108 conidia/ml) 8 days post-inoculation. Likewise, in the laboratory bioassay, B. tabaci, adults, Cjc-03 isolate exhibited maximum mortality (80.0%), followed by Cjw-01 isolate (77.5%), and TS-01 isolate (65.0%) at the concentration of 1 × 107 conidia/ml at 7 days post-inoculation. The highest mortality rate (63.45%) was recorded by the Cjc-03 isolate and TS-01 (54.22%) isolate at 3 days post-inoculation in glasshouse bioassay using the concentration of 1 × 107 conidia/ml of each of the 2 isolates (Cjc-03 and TS-01) against B. tabaci adults. Conclusion Overall, the findings showed that both isolates of I. javanica and P. lilacinum reduced the number of eggs, nymphs, and adults’ emergence of B. tabaci, following the application of 1 × 107 conidia/ml on tomato leaves in the glasshouse. The newly isolated strains could be developed as a potential commercial biopesticide for managing B. tabaci.

Rhynchophorus ferrugineus (Olivier) (Coleoptera: Dryophthoridae) is an economically important pest of palm trees in the subtropics. Beauveria bassiana (Balsamo-Crivelli) Vuillemin (Hypocreales: Clavicipitaceae), has been shown to be pathogenic against R. ferrugineus in laboratory and field studies. However, because they remain inside the trunks until adulthood, the slowing of feeding and increases in mortality of internally feeding R. ferrugineus larvae over time after B. bassiana treatment has not been established. To explore the potential of acoustic methods to assess treatment effects, sound impulses produced by untreated, 104-, and 106-conidia ml-1B. bassiana-treated larvae in palms were recorded for 23 d, after which the palms were dissected and the larvae examined. Analyses were performed to identify trains of impulses with characteristic patterns (bursts) produced frequently by moving and feeding larvae but only rarely (3–8% of the larval rate) by interfering background noise or tree vibrations. The rates of bursts, the counts of larval impulses per burst, and the rates of impulses in bursts decreased significantly over time in both B. bassiana treatments but not in the control. This supports a hypothesis that larvae had briefer movement and feeding bouts as they became weaker after infection, which reduced the counts of larval impulses per burst, the rates of bursts, and the rates of impulses in bursts. There is considerable potential for use of acoustic methods as tools for nondestructive assessment of effects of biological control treatments against internally feeding insect pests.

The red palm weevil (RPW) is a notorious phytophagous pest infesting various palm species around the world. In Malaysia, the RPW was known to cause damage on coconuts in the East Coast regions of the Peninsula and posed risks to oil palms. Thus, early detection and monitoring studies of RPW in both coconuts and oil palms by using acoustic sensors were carried out at Dungun, Terengganu and Tanah Merah, Kelantan. The smart sensor identified the presence of RPW within the coconuts and oil palms. Continuous monitoring of RPW using acoustic sensors is needed to avoid the risk of spreading of this cryptic borer, especially in oil palm plantations.

The red palm weevil (RPW) is a stem boring Coleoptera that decimates host palm trees from within. The challenge of managing this pest is due to a lack of physical symptoms during the early stages of infestation. Investigating the physiological changes that occur within RPW-infested palm trees may be useful in establishing a new approach in RPW detection. In this study, the effects of RPW infestation were investigated in Elaeis guineensis by observing changes in physical and physiological parameters during the progress of infestation by visual inspection and the comparison of growth, gas exchange, stomatal conductance, and chlorophyll content between the non-infested control, physically wounded, and RPW-infested E. guineensis groups. During the study period, four distinct levels of physical infestation were observed and recorded. The RPW-infested group displayed significantly lower maximum photosynthesis activity (Amax) starting from the third week post-infestation. However, growth in terms of change in plant height and stem circumference, leaves’ stomatal conductance, and chlorophyll content were not significantly different between the three groups during the duration of the study. The significant drop in photosynthesis was observed one week before physical changes appeared. This suggests the promising utilisation of photosynthesis activity as a signal for detecting RPW infestation at the early stage of attacks, which could be useful for integration in integrated pest management (IPM).

This work was supported by the Spanish Ministry of Science and Innovation AGL2015-66833-R project, the Universiti Kebangsaan Malaysia, and the Malaysia Ministry of Higher Education. Project was also partially supported by MUSA project (727624). The results of this paper have been filed for a Spanish Patent (P201631534).

The red palm weevil (RPW; Rhynchophorus ferrugineus Olivier (Coleoptera Curculionidae)) is an invasive insect pest that is difficult to manage due to its nature of infesting the host palm trees from within. A holistic, molecular-based approach to identify proteins that correlate with RPW infestation could give useful insights into the vital processes that are prevalent to the host’s infestation response and identify the potential biomarkers for an early detection technique. Here, a shotgun proteomic analysis was performed on oil palm (Elaeis guineensis; OP) under untreated (control), wounding by drilling (wounded), and artificial larval infestation (infested) conditions at three different time points to characterise the RPW infestation response at three different stages. KEGG pathway enrichment analysis revealed many overlapping pathways between the control, wounded, and infested groups. Further analysis via literature searches narrowed down biologically relevant proteins into categories, which were photosynthesis, growth, and stress response. Overall, the patterns of protein expression suggested abscisic acid (ABA) hormone signalling to be the primary driver of insect herbivory response. Interspecies molecular docking analysis between RPW ligands and OP receptor proteins provided putative interactions that result in ABA signalling activation. Seven proteins were selected as candidate biomarkers for early infestation detection based on their relevance and association with ABA signalling. The MS data are available via ProteomeXchange with identifier PXD028986. This study provided a deeper insight into the mechanism of stress response in OP in order to develop a novel detection method or improve crop management.