Resistance of diamondback moth (DBM), Plutella xylostela (L), to coventional pesticides and concerns about environmental quality have lead to increased worldwide efforts to develop viable biocontrol methods for DBM. The success of using parasitoids, especially larval parasitoids like Diadegma, Cotesia and Microplitis species for controlling DBM have been reported in several countries. These larval parasitoids of DBM are commonly found in the field. Diadegma semiclausum (=eucerophaga) Hellen is the major parasitoid of DBM in Europe and Asia, while Diadegma insulare (Cresson) are predominates in the Americas. To date, the bacterium, Bacillus thuringiensis Berliner subspecies kurstaki, has been the most widely used DBM pathogen. Although it is environment friendly pesticides, its effectiveness always vary with weather, field location and frequency of application per season. These are the main factors that contribute to the slow acceptance of B.thuringiensis by the cabbage growers worldwide. Because of this many studies have been done to improve its efficacay and persistence in the field. This paper provides an overview of the current status of these agents for use in controlling DBM and suggest research that is needed to improve the usefulness of these biocontrol agents and to maximize their impact on the DBM management in the future.
Ketahanan rama-rama belakang-intan (diamondback moth), Plutella xylostella (L.), kepada semua racun-racun perosak yang biasa digunakan untuk mengawalnya dan keprihatinan terhadap kualiti alam sekitar telah menyebabkan bertambahnya usaha mencari beberapa kaedah kawalan biologi rama-rama ini di seluruh dunia. Kejayaan menggunakan parasitoids, terutamanya parasitoid larva seperti spesies Diadegma, Cotesia dan Microplitis bagi kawalan serangga ini telah dilaporkan oleh beberapa negara. Parasitoid-parasitoid larva ini mudah didapati di lapangan. Diadegma semiclausum (=eucerophaga) Hellen adalah merupakan parasitoid utama di Eropah dan Asia, sementara Diadegma insulare (Cresson) predominen di benua America. Sehingga kini, bakteria Bacillus thuringiensis Berliner subspesies kurstaki, adalah sejenis patogen serangga yang digunakan secara meluas untuk mengawal rama-rama tersebut. Walaupun B. thuringiensis adalah sejenis racun makhluk perosak yang tidak mencemari alam sekitar, tahap keberkesanan tindakannya adalah kerap berubah-ubah mengikut perubahan cuaca, lokasi lapangan dan kekerapan penggunaannya. Ini adalah merupakan faktor-faktor penting yang menyebabkan kelambatan penerimaannya oleh penanam-penanam kobis di merata dunia. Oleh sebab inilah banyak kajian telah dan sedang dijalankan bagi memperbaiki tahap keberkesanan dan persistentnya di lapangan. Kertas ini disedia bagi memperihalkan status penggunaan kedua-dua jenis agen kawalan biologi disamping mengesyurkan penyelidikan yang perlu dibuat untuk mempertingkatkan kegunaan dan memaksimumkan dampaknya dalam pengurusan rama-rama ini masa akan datang.
Aedes aegypti and Aedes albopictus are the principle dengue vectors in Malaysia. The presence and distribution of Aedes larvae were studied in three different localities in Kelantan, Terengganu and Sabah, Malaysia in October 2008, November 2008 and June 2009. Two hundred (200) ovitraps per locality were placed randomly indoors and outdoors, depending on the environment of each locality. The highest mean number of Ae. aegypti and Ae. albopictus larvae per recovered ovitrap for both indoors and outdoors was obtained from Kg. Paya Rambai, Kelantan. The indoor populations of Ae. aegypti as well as the indoor and outdoor populations of Ae. albopictus in Kg. Paya Rambai, Kelantan were significantly higher than the other two study sites (p<0.05) by 1.03- and 4.67-folds, 2.36- and 5.84-folds and 1.98- and 4.00-folds, respectively. Both Ae. aegypti and Ae. albopictus were also found to breed within the same ovitraps placed indoors and outdoors in all study sites ranging from 15.22% to 31.82% of the total positive ovitraps. This study showed that both species could serve as the vectors of dengue in all study sites as indicated by the high populations recorded. The reliability and sensitivity of ovitraps in Aedes surveillance was also proven.
Ficus plants are commonly planted as ornamentals along roadsides in Malaysia. In 2010, Ficus plants in Kuala Terengganu were found to be attacked by a moth, identified as Trilocha varians. The larvae of this moth fed on Ficus leaves causing up to 100% defoliation. This study was conducted to determine the life cycle of T. varians under two different environmental temperatures and to control this pest using two different insecticides. Our findings showed that there were significant differences in the time taken for eggs to hatch and larval and pupation period between low and high environmental temperatures. Results also showed that fipronil had lower LT50 and LT95 than malathion. This study provides new information on the life history of T. varians under two different conditions and the efficiency in controlling T. varians larvae using insecticides. The results of this study are important for future management in controlling T. varians population especially in Kuala Terengganu, Malaysia.
In a forensic acarology study, conducted in a secondary forest of Forensic Science Simulation Site, Universiti Kebangsaan
Malaysia (UKM) in Bangi, Selangor, six carcasses consisted of three monkeys and three rabbits were placed individually
in steel enclosures and observed for 35 days. The carcasses, the soil beneath them and pitfall traps were checked daily
for insects and mites. A species of mesostigmatid mite, Macrocheles scutatiformis was discovered and this is a first time
reported in Malaysia. There are about 94.0% of Macrocheles present inside the cages of the monkey and rabbit carcasses.
Most mites in this study were collected from soil beneath the carcasses, on a dung beetle and a Chrysomya rufifacies
larva. Our findings showed that M. scutatiformis have a potential role in forensic investigation involving dead animals
perhaps corpses especially during the dry stage of decomposition.
AISYAH ABU BAKARRed palm weevil (RPW), Rhynchophorus ferrugineus has been reported as a serious pest of coconut, sago palm and date palm in many parts of the world. In Malaysia, RPW is a lethal pest of coconut in Terengganu and sago palm in Sarawak. However, very limited information about the reproductive performance of RPW is available, specifically in Malaysia. In the present study, the reproductive performance of RPW reared on sago palm (Metroxylon sagu) were studied using nine pairs of virgin RPW under laboratory conditions. The number of eggs laid and eggs viability were recorded daily until females could not produce eggs. The total number of eggs laid were 3081 and the average number of eggs deposited by a female was 342.3+0.97 eggs (ranged from 270 to 396). The percentage of hatchability was 52.4% and out of the total 1614 hatched eggs, only 118 individuals (7.3%) were survived until late instar. However, no significant differences in fecundity, hatchability and total survived larvae in different RPW pairs were observed. Females longevity was found to be strongly influenced by the number of eggs laid; the higher number of eggs laid, the shorter is the life span of the female. This study is important to understand the biological aspects of RPW, as a first step to develop effective control strategy of the pest.
Rhynchophorus ferrugineus or red palm weevil (RPW) is a destructive insect pest of major cultivated palms such as coconut, date and oil palm. One of the control management of RPW is trunk injection using monocrotophos or methamidophos, but these chemicals are found to affect ecosystems and human health. Thus, we aimed to determine a bio-pesticide to replace these synthetic chemicals. We tested the antifeedant activity of three eugenol-based compounds as potential control agent against RPW larvae in vitro condition for two weeks. All these compounds show significant effect as feeding deterrent agent on 4th instar larvae, while WN16 (4-allyl-2-methoxy-1-(4-trifluoromethyl-benzyloxy)-benzene) shows the highest feeding deterrent index (FDI = 64.42%). Here we present the data regarding the biological aspect on treated RPW larvae as well as antifeedant activity index of these eugenol derived compounds.
The population genetic structures of S. vanluni, S. cheongi and S. jeffreyi were determined from mitochondria-encoded sequences of cytochrome c oxidase subunits I (COI) across different states in Peninsular Malaysia. High levels of genetic diversity and genetic differentiation were observed among three species. All three species revealed an intermediate level of gene flow among the populations. Negative values of Fu's Fs and low values of Raggedness index supported the hypothesis of population expansion in S. vanluni, S. cheongi and S. jeffreyi.
Surface engineering of super paramagnetic iron oxide nanoparticles (SPIONs) favor the tagging of any molecule or compound onto it, encapsulating them with a biopolymer make them biocompatible and favor slow release of loaded molecules. Recovery of SPIONs is easier as they obey to external magnetic field. In this study, SPIONS were used for mosquito larvicidal activity after surface engineered with oleic acid to favor the tagging of Cyfluthrin (mosquito larvicidal agent), it was then encapsulated with gum polysaccharide derived from Azadirachta indica and Araucaria heterophylla. Every stage of coreshell formation was microscopically and spectroscopically characterized. The coreshell SPIONs produced using Azadirachta indica and Araucaria heterophylla gum derived polysaccharide encapsulation were found to be the size around 80 nm. Thus, prepared coreshell SPIONs was subjected for mosquito larvicidal activity against Culex sp. The coreshell SPIONs was efficiently killing the mosquito larva and its impact was studied by percentage mortality studies.
Ancyronyx clisterisp. nov. (Coleoptera, Elmidae) a new spider riffle beetle discovered from northern Borneo (Brunei; Sabah and Sarawak, Malaysia) and the larva of Ancyronyx sarawacensis Jäch are described. Illustrations of the habitus and diagnostic characters of the new species and the similar and highly variable A. sarawacensis are presented. Differences to closely related species, based on DNA barcodes and morphological characters, are discussed. Association of the larva and the imago of A. sarawacensis, and the occurrence of Ancyronyx procerus Jäch in Peninsular Malaysia and Sabah are confirmed by using COI mtDNA sequences.
Maggot therapy, also known as maggot debridement therapy, larval therapy, biodebridement, or biosurgery, is a type of biotherapy involving the intentional application of live, disinfected fly larvae or maggots into the nonhealing wound of a human or animal to debride the necrotic wound, reduce bacterial contamination of the wound as well as enhance the formation of healthy granulation tissue and stimulate healing in nonhealing wounds. In addition, van der Plas et al reported that the use of the medicinal larvae as natural remover of necrotic and infected tissue had prevented amputation in 11 selected patients. In Malaysia, Aaron et al had demonstrated prevention of amputation in 25 patients.
Fumonisin B1 (FB1) is a common mycotoxin produced by Fusarium species particularly F. proliferatum and F. verticillioides. The toxin produced can cause adverse effects on humans and animals. The objectives of this study were to detect the production of FB1 based on the amplification of FUM1 gene, to quantify FB1 produced by the isolates using Ultra-fast Liquid Chromatography (UFLC) analysis, to examine the embryotoxicity effect of FB1 and to determine EC50 toward the larvae of zebrafish (Danio rerio). Fifty isolates of Fusarium species were isolated from different hosts throughout Malaysia. Successful amplification of the FUM1 gene showed the presence of this gene (800 bp) in the genome of 48 out of 50 isolates. The highest level of FB1 produced by F. proliferatum isolate B2433 was 6677.32 ppm meanwhile F. verticillioides isolate J1363 was 954.01 ppm. From the assessment of embryotoxicity test of FB1 on larvae of zebrafish, five concentrations of FB1 (0.43 ppm, 0.58 ppm, 0.72 ppm, 0.87 ppm and 1.00 ppm) were tested. Morphological changes of the FB1 exposed-larvae were observed at 24 to 168 hpf. The mortality rate and abnormality of zebrafish larvae were significantly increased at 144 hpf exposure. Meanwhile, the spontaneous tail coiling showed a significant difference. There were no significant differences in the heartbeat rate. As a conclusion, the presence of FUM1 in every isolate can be detected by FUM1 gene analysis and both of the species produced different concentrations of FB1. This is the first report of FB1 produced by Fusarium species gave a significant effect on zebrafish development.
Cocoa bean (Theobroma cacao L.) is part of the global cocoa and chocolate industry valued at 44 billion US dollars in 2019. Cocoa pod borer (CPB), Conopomorpha cramerella is a major pest of cocoa in Malaysia and Indonesia that is responsible for the decline for cocoa production. They have been detected since 1980s. Unfortunately, current control strategies are inefficient for CPB management. Although biotechnological alternatives, including RNA interference (RNAi), have been proposed in recent years to control insect pests, characterizing the genetics of the target pest is essential for successful application of these emerging technologies. We generated a comprehensive RNA-seq dataset (135,915,430 clean reads) for larva and adult stages of CPB by using the Illumina HiseqTM 4000 system to increase the understanding of CPB in relation to molecular features. The CPB transcriptome was assembled de novo and annotated. The final assembled produced 249,280 unigenes, of which 75,929 unigenes annotated against NCBI NR database and were distributed among 156 KEGG pathways. The raw data were uploaded to SRA database and the BioProject ID is PRJNA553611. The transcriptomic dataset we present are the first reports of transcriptome information in CPB that is valuable for further exploration and understanding of CPB molecular pathways.
Alphacypermethrin (Fendona) and lambda-cyhalothrin (Icon) were evaluated against sentinel bloodfed adults and 4th-instar larvae of Aedes aegypti in a housing estate in Malaysia. The impact of both pyrethroids on field populations of Ae. aegypti and Aedes albopictus were monitored weekly using oviposition trap samples. Both alphacypermethrin and lambda-cyhalothrin showed adulticidal and larvicidal effects.
Between April 1987 and March 1988, populations of immature Aedes albopictus and Toxorhynchites spp. in bamboo pots were sampled weekly. Populations of Ae. albopictus and rainfall varied from month to month. During the heavy rainfall months of September and October 1987, larval counts of Ae. albopictus were high, between 30.8 and 49.2 larvae per week compared to 16 larvae per week during the low rainfall month of January 1988. A higher population of Toxorhynchites spp. was associated with a low population of the vector.
An Aedes survey using various larval survey methods was conducted in 12 urban housing areas and 29 vacant lands in Sibu town proper. Aedes albopictus larvae were found in all areas surveyed while Aedes aegypti larvae were present in 10 localities and 4 vacant lands. There were no significant difference in the house index, breteau and larval density index of these two Aedes (Stegomyia) species from the survey areas. The proportion of containers positive with Ae. aegypti and Ae. albopictus in area outside the house compound and near the house fencing were 3.2 times higher than outdoor compound. The indoor/outdoor breeding ratio for Ae. aegypti alone is 1.6:1. The most preferred breeding habitats outdoor were plastic cups and used tires while indoor habitats were ant traps and flower vases. In the vacant lands, the average number of larvae per containers was significantly higher than in houses and over 51% of the containers inspected were positive. Shared breeding between Ae. aegypti and Ae. albopictus larvae accounted for 9% in house surveys and 4.5% in vacant land survey. The use of various methods in Aedes larval survey may provide essential information in the study of vector epidemiology in dengue and dengue hemorrhagic fever transmission.
Mosquitocidal strains of B. sphaericus serotype H-5a5b were shown for the first time to exhibit antagonistic activities against several human pathogens especially Salmonella. These strains of B. sphaericus also exhibited high larval toxicity against several mosquitoes.
A gene encoding the larval excretory-secretory antigen TES-120 of the dog ascarid worm Toxocara canis was cloned into the methylotrophic yeast Pichia pastoris. Specificity of the recombinant TES-120 antigen produced by the yeast was investigated. Forty-five human serum samples from patients infected with different()parasitic organisms, including 8 cases of toxocariasis, were tested against the recombinant antigen in immunoblot assays. Results from the assays showed that the recombinant TES-120 antigen reacted with sera from toxocariasis patients only. This highly specific recombinant TES-120 antigen can potentially be used for the development of an inexpensive serodiagnostic assay for human toxocariasis.
Marine biofouling causes problems to marine structure and obstructs condenser tubes in cooling systems which use sea water as the coolant. The main purpose of this study is to investigate the seasonal ecology of biofouling organisms such as the green mussel, Perna viridis, the dominant fouling species in the Eastern Johore Straits at the Senoko Power Station. The spawning time and its relationship with environmental conditions were studied. The physical, chemical and biological conditions of the sea at Senoko were monitored for a year. Settling slides were used to study the fouling succession in different monsoon seasons. The study showed that there were two main spawning peaks for the green mussel and that these peaks occurred during the intermonsoon months of November and April. These peaks were also correlated with the bimodal patterns for salinity, dissolved oxyen, bivalve veliger larval density and total plankton biomass of the Eastern Johore Strait water. Succession patterns were similar during the two monsoon seasons, however, the rate of fouling was probably greater during the southwest monsoon months. It is therefore advisable that the control or reduction of biofouling in Eastern Johore Strait should take into account the seasonal fluctuations and spawning of the fouling organisms.
Leptotrombidium (Leptotrombidium) umbricola, described here as a new species, is a member of the L. (L.) deliense group and most closely resembles L. (L.) vivericola. L. (L.) umbricola was collected from the ground surface and from animal hosts, in similar habitats to the scrub typhus vector, L. (L.) deliense. The host and habitat distribution records and the Rickettsia tsutsugamushi infection rates within unengorged specimens suggest that L. (L.) umbricola may be an important vector of scrub typhus in Peninsular Malaysia.