Nine populations of three species of Nephotettix (Insecta: Hemiptera) from Peninsular Malaysia were analysed for nine enzymes comprising 11 loci. Nei's (Genetics 89, 583, 1978) genetic distance, D, between N. virescens and N. malayanus was 0.181, that between N. virescens and N. nigropictus was 0.283, and that between N. malayanus and N. nigropictus was 0.203. The genetic distance between N. nigropictus from rice plant and from the weed-grass L. hexandra at Universiti Pertanian Malaysia was 0.004 and their genetic identity was 0.996, thus indicating that this insect species fees on both host plants. The proportion of polymorphic loci and the observed heterozygosities were higher in N. nigropictus, with a wider range of host plants, than in N. virescens and N. malayanus, restricted to rice and L. hexandra, respectively.
Phytoplasmas (mycoplasmalike organisms, MLOs) associated with mitsuba (Japanese hone-wort) witches'-broom (JHW), garland chrysanthemum witches'-broom (GCW), eggplant dwarf (ED), tomato yellows (TY), marguerite yellows (MY), gentian witches'-broom (GW), and tsu-wabuki witches'-broom (TW) in Japan were investigated by polymerase chain reaction (PCR) amplification of DNA and restriction enzyme analysis of PCR products. The phytoplasmas could be separated into two groups, one containing strains JHW, GCW, ED, TY, and MY, and the other containing strains GW and TW, corresponding to two groups previously recognized on the basis of transmission by Macrosteles striifrons and Scleroracus flavopictus, respectively. The strains transmitted by M. striifrons were classified in 16S rRNA gene group 16SrI, which contains aster yellows and related phytoplasma strains. Strains GW and TW were classified in group 16SrIII, which contains phytoplasmas associated with peach X-disease, clover yellow edge, and related phytoplasmas. Digestion of amplified 16S rDNA with HpaII indicated that strains GW and TW were affiliated with subgroup 16SrIII-B, which contains clover yellow edge phytoplasma. All seven strains were distinguished from other phytoplasmas, including those associated with clover proliferation, ash yellows, elm yellows, and beet leafhopper-transmitted virescence in North America, and Malaysian periwinkle yellows and sweet potato witches'-broom in Asia.
Entomopathogenic fungi of the genus Aschersonia are specific for whitefly and scale insects. They can be used as biological control agents against silverleaf whitefly, Bemisia argentifolii and greenhouse whitefly, Trialeurodes vaporariorum. Forty-four isolates of Aschersonia spp. were tested for their ability to sporulate and germinate on semi-artificial media and to infect insect hosts. Seven isolates sporulated poorly (less than 1x10(7) conidia/dry weight) and 10 were not able to infect either of the whitefly species. Several isolates were able to produce capilliconidia. Infection level was not correlated with germination on water agar. After a selection based on spore production and infection, virulence of 31 isolates was evaluated on third instar nymphs of both whitefly species on poinsettia (Euphorbia pulcherrima). Whitefly infection levels varied between 2 and 70%, and infection percentages of B. argentifolii correlated with that of T. vaporariorum. However, mortality was higher for T. vaporariorum than for B. argentifolii, as a result of a higher 'mortality due to unknown causes.' Several isolates, among which unidentified species of Aschersonia originating from Thailand and Malaysia, A. aleyrodis from Colombia, and A. placenta from India showed high spore production on semi-artificial medium and high infection levels of both whitefly species.
Whitefly-transmitted, cucurbit-infecting begomoviruses (genus Begomovirus, family Geminiviridae) have been detected on cucurbit crops in Bangladesh, China, Egypt, Israel, Malaysia, Mexico, the Philippines, Thailand, United States, and Vietnam. Pumpkin plants showing leaf curling, blistering, and yellowing symptoms were observed in the AVRDC fields (Tainan, Taiwan) during 2001 and in nearby farmers' fields during 2005. Two samples from symptomatic plants were collected in 2001 and six collected in 2005. Viral DNAs were extracted (2), and the PCR, with previously described primers, was used to detect the presence of begomoviral DNA-A (4), DNA-B (3), and associated satellite DNA (1). Begomoviral DNA-A was detected in one of the 2001 samples and in all 2005 samples. The PCR-amplified 1.5 kb viral DNA-A from one positive sample each from the 2001 and 2005 collections was cloned and sequenced. On the basis of the 1.5-kb DNA-A sequences, specific primers were designed to completely sequence the DNA-A component. The overlap between fragments obtained using primer walking ranged from 43 to 119 bp with 100% nt identities. The complete DNA-A sequences were determined for the two isolates as 2,734 bp (2001) (GenBank Accession No. DQ866135) and 2,733 bp (2005) (GenBank Accession No. EF199774). Sequence comparisons and analyses were performed using the DNAMAN Sequence Analysis Software (Lynnon Corporation, Vaudreuil, Quebec, Canada). The DNA-A of the begomovirus isolates each contained the conserved nanosequence-TAATATTAC and six open reading frames, including two in the virus sense and four in the complementary sense. On the basis of a 99% shared nucleotide sequence identity, they are considered isolates of the same species. BLASTn analysis and a comparison of the sequence with others available in the GenBank database ( http://www.ncbi.nlm.nih.gov ) indicated that the Taiwan virus shared its highest nt identity (more than 95%) with the Squash leaf curl Philippines virus (GenBank Accession No. AB085793). Virus-associated satellite DNA was not found in any of the samples. DNA-B was found in both samples, providing further evidence that the virus was the same as the bipartite Squash leaf curl Philippines virus. To our knowledge, this is the first report of Squash leaf curl Philippines virus in Taiwan. References: (1) R. W. Briddon et al. Virology 312:106, 2003. (2) R. L. Gilbertson et al. J. Gen. Virol. 72:2843, 1991. (3) S. K. Green et al. Plant Dis. 85:1286, 2001. (4) M. R. Rojas et al. Plant Dis. 77:340, 1993.
The inheritance of 31 amplicons from short and long primer RAPD was tested for segregating ratios in two families of the brown planthopper, Nilaparvata lugens, and they were found to be inherited in a simple Mendelian fashion. These markers could now be used in population genetics studies of N. lugens. Ten populations of N. lugens were collected from five locations in Malaysia. Each location had two sympatric populations. Cluster and principal coordinate analyses based on genetic distance along with AMOVA revealed that the rice-infesting populations (with high esterase activity) at five localities clustered together as a group, and Leersia-infesting populations (with low esterase activity) at the same localities formed another distinct cluster. Two amplicons from primers OPD03 (0.65 kb) and peh#6 (1.0 kb) could be considered diagnostic bands, which were fixed in the Leersia-infesting populations. These results represent evidence of a sibling species in the N. lugens complex.
Rice brown planthopper, Nilaparvata lugens Stål, is a primary insect pest of cultivated rice, and effective control is essential for economical crop production. Resistance to neonicotinoid insecticides, in particular imidacloprid, has been reported as an increasing constraint in recent years. In order to investigate the extent of resistance, 24 samples of N. lugens were collected from China, India, Indonesia, Malaysia, Thailand and Vietnam during 2005 and 2006. Their responses to two diagnostic doses of imidacloprid (corresponding approximately to the LC(95) and 5 x LC(95) of a susceptible strain) were examined.
In August 2008, 30% of tomato (Solanum lycopersicum) plants in plots in Lubbock County, Texas showed yellowing, lateral stem dieback, upward leaf curling, enlargement of stems, adventitious roots, and swollen nodes. Yellowing in leaves was similar to that seen with zebra chip disease (ZC) of potato that was confirmed in a potato field 112 km away in July 2008 and was associated with a 'Candidatus Liberibacter' species (1), similar to findings earlier in 2008 in New Zealand and California (2,3). Tissue from four symptomatic plants of cv. Spitfire and two of cv. Celebrity were collected and DNA was extracted from midribs and petioles with a FastDNA Spin Kit (Qbiogene, Inc., Carlsbad, CA,). PCR amplification was done with 16S rRNA gene primers OA2 and OI2c, which are specific for "Ca. Liberibacter solanacearum" from potato and tomato and amplify a 1.1-kb fragment of the 16S rRNA gene of this new species (1,3). Amplicons of 1.1 kb were obtained from all samples and these were sequenced in both orientations (McLab, San Francisco, CA). Sequences of the 16S rRNA gene were identical for both Spitfire and Celebrity and were submitted to the NCBI as GenBank Accession Nos. FJ939136 and FJ939137, respectively. On the basis of a BLAST search, sequence alignments revealed 99.9% identity with a new species of 'Ca. Liberibacter' from potato (EU884128 and EU884129) in Texas (1); 99.7% identity with the new species "Ca. Liberibacter solanacearum" described from potato and tomato (3) in New Zealand (EU849020 and EU834130, respectively) and from the potato psyllid Bactericera cockerelli in California (2) (EU812559, EU812556); 97% identity with 'Ca L. asiaticus' from citrus in Malaysia (EU224393) and 94% identity with both 'Ca. L. africanus' and 'Ca. L. americanus' from citrus (EU921620 and AY742824, respectively). A neighbor-joining cladogram constructed using the 16S rRNA gene fragments delineated four clusters corresponding to each species, and these sequences clustered with "Ca. L. solanacearum". A second PCR analysis was conducted with the CL514F/CL514R primer pair, which amplifies a sequence from the rplJ and rplL ribosomal protein genes of "Ca. L. solanacearum". The resulting 669-bp products were 100% identical to a sequence reported from tomato in Mexico (FJ498807). This sequence was submitted to NCBI (GU169328). ZC, a disease causing losses to the potato industry, is associated with a 'Candidatus Liberibacter' species (1-3) and was reported in Central America and Mexico in the 1990s, in Texas in 2000, and more recently in other states in the United States (4). In 2008, a "Ca. Liberibacter solanacearum" was detected on Capsicum annuum, S. betaceum, and Physalis peruviana in New Zealand (3). Several studies have shown that the potato psyllid, B. cockerelli, is a potential vector for this pathogen (2,4). To our knowledge, this is the first report of "Ca. Liberibacter solanacearum" in field tomatoes showing ZC-like foliar disease symptoms in the United States. References: (1). J. A. Abad et al. Plant Dis. 93:108, 2009 (2) A. K. Hansen et al. Appl. Environ. Microbiol. 74:5862, 2008. (3) L. W. Liefting et al. Plant Dis. 93:208, 2009. (4) G. A. Secor et al. Plant Dis. 93:574, 2009.
Survival and fertility characteristics of the brown planthopper (BPH), Nilaparvata lugens were assessed in the laboratory and field. Life tables and population parameters of the BPH were constructed in an environment with unlimited food supply and that was free of natural enemies. The highest mortality occurred in the immature stage, especially in the first and second instars. The life table analysis showed that the population density of BPH decreased gradually. The survival ratio of male to female was 0.512:0.488. The females lived for a maximum of 20 days. The trend of oviposition showed a peak at around the tenth day of the female life. The highest number of eggs produced per female per day was 9.63. The intrinsic rate of increase (rm) in egg production per female per day was 0.0677 and the daily finite of increase (λ) was 1.0688 females per female per day, with a mean generation time (T) of 34.05 days. The net reproductive rate (Ro) of the population was 10.02. The population doubling time (DT) was 10.42 days.
Asopines are predators of insects, with several species with potential as biocontrol agents of a number of pests. Metrogaleruca obscura (Degeer), a neotropical species of Galerucini, was introduced in Malaysia, Asia, and Mauritius, Africa, to control the spread of Cordia curassavica (Boraginaceae), a native plant of the neotropics. The occurrence of Podisus nigrispinus (Dallas) preying on M. obscura is recorded, and Cordia verbenacea (Boraginaceae) is mentioned as a host plant for M. obscura. A list of Chrysomelidae attacked by asopines in the neotropical region is also presented.
Four new species of Tambinia Stål (Hemiptera: Fulgoromorpha: Tropiduchidae), Tambinia conussp. n. (Papua New Guinea), Tambinia maculasp. n. (Malaysia: Borneo), Tambinia robustocarinasp. n. (Malaysia: Sabah) and Tambinia sexmaculatasp. n. (Australia: Kuranda) are described and illustrated from the Pacific region. The diagnostic characters of this genus are redefined. A checklist and a key to the known species of Tambinia are provided.
Direct amplified length polymorphism (DALP) combines the advantages of a high-resolution fingerprint method and also characterizing the genetic polymorphisms. This molecular method was also found to be useful in brown planthopper, Nilaparvata lugens species complex for the analysis of genetic polymorphisms. A total of 11 populations of Nilaparvata spp. were collected from 6 locations from Malaysia. Two sympatric populations of brown planthopper, N. lugens, one from rice and the other from a weed grass (Leersia hexandra), were collected from each of five locations. N. bakeri was used as an out group. Three oligonucleotide primer pairs, DALP231/DALPR'5, DALP234/DALPR'5, and DALP235/DALPR'5 were applied in this study. The unweighted pair group method with arithmetic mean (UPGMA) dendrogram based on genetic distances for the 11 populations of Nilaparvata spp. revealed that populations belonging to the same species and the same host type clustered together irrespective of their geographical localities of capture. The populations of N. lugens formed into two distinct clusters, one was insects with high esterase activities usually captured from rice and the other was with low esterase activities usually captured from L. hexandra. N. bakeri, an out group, was the most isolated group. Analyses of principal components, molecular variance, and robustness also supported greatly to the findings of cluster analysis.
Aspects of the incidence and spread of the citrus disease huanglongbing (HLB) in relation to the vector Diaphorina citri population fluctuation were studied from January 1999 to December 2001 seasons in a 0.8 ha citrus orchard at Jemukan (1° 33'N, 110° 41'E), Southwest Sarawak in Malaysia. In relation to insecticide and horticultural mineral oils (HMOs) use, levels of HLB infection rose quite rapidly over the next 3 years in the unsprayed control and less rapidly in the other treatments such as imidacloprid, nC24HMO, and triazophos/cypermethrin/chlorpyrifos. Levels of HLB as determined by Polymerase Chain Reaction (PCR) were 42.2%, 9.4%, 11.4%, and 22.7%, respectively. The effects of nC(24)HMO and conventional pesticides on the citrus psyllid population and parasitoids in citrus orchard were also determined.
Contamination of insect DNA for RAPD-PCR analysis can be a problem because many primers are non-specific and DNA from parasites or gut contents may be simultaneously extracted along with that of the insect. We measured the quantity of food ingested and assimilated by two sympatric populations of brown planthopper (BPH), Nilaparvata lugens, one from rice and the other from Leersia hexandra (Poaceae), a wetland forage grass, and we also investigated whether host plant DNA contaminates that of herbivore insects in extractions of whole insects. Ingestion and assimilation of food were reduced significantly when individuals derived from one host plant were caged on the other species. The bands, OPA3 (1.25), OPD3 (1.10), OPD3 (0.80), OPD3 (0.60), pUC/M13F (0.35), pUC/M13F (0.20), BOXAIR (0.50), peh#3 (0.50), and peh#3 (0.17) were found in both rice-infesting populations of brown planthopper and its host plant (rice). Similarly, the bands, OPA4 (1.00), OPB10 (0.70), OPD3 (0.90), OPD3 (0.80), OPD3 (0.60), pUC/ M13F (0.35), pUC/M13F (0.20), and BOXAIR (0.50) were found in both Leersia-infesting populations of brown planthopper and the host plant. So, it is clear that the DNA bands amplified in the host plants were also found in the extracts from the insects feeding on them.
Morphological and host-plant relationship studies were conducted to differentiate two sympatric populations of brown planthopper (BPH), Nilaparvata lugens, one from rice (Oryza sativa) and the other from Leersia hexandra, a weed grass. In morphometric studies based on esterase activities, an UPGMA dendrogram using 17 quantitative morphological characters, including stridulatory organs (courtship signal-producing organs) between two sympatric populations of N. lugens, one from rice and the other from L. hexandra, a weed grass revealed that both populations were separated from each other. An out-group, N. bakeri, was found to be completely different from the two sympatric populations of N. lugens. Rice plants were best suited for the establishment of the rice-infesting population, and L. hexandra was a favourable host for the Leersia-infesting population. The individuals derived from one host did not thrive on the other host, as shown by a significant reduction in survival and nymphal development, ovipositional preferences, ovipositional response, and egg hatchability. Therefore, morphological and host-plant relationship studies indicate that rice-associated population with high esterase activities and L. heaxandra-associated population with low esterase activities are two closely related sibling species.
The leafhopper subfamily Signoretiinae is redescribed and includes two tribes: Signoretiini Baker and Phlogisini Linnavuori. Redescriptions of included tribes, diagnoses and a taxonomic key to genera are provided. New records for genera of Signoretiinae are as follows: Phlogis in Central African Republic, Malaysia and Thailand; Preta in Thailand; and Signoretia in the Republic of the Congo, Zambia, Thailand, Vietnam, and Taiwan (China). Signoretia pacifica is newly recorded from Cameroon. In addition, detailed illustrations of the male genitalia of the previously described species, Chouious tianzeus, Preta gratiosa,and Signoretia yangli are provided; the male genitalia of Signoretia malaya are described for the first time; and two new species of Signoretia are described, Signoretia delicata sp. n. from the Philippinesand Signoretia kintendela sp. n. from the Republic of the Congo.
Two new monotypic spittlebug genera and their type species in the family Machaerotidae, subfamily Enderleiniinae, are described and illustrated: Labramachaerota korupa gen. & sp. n. (with type locality in Cameroon) and Kyphomachaerota maaia gen. & sp. n. (with type locality in Sarawak, Malaysia).
Matched MeSH terms: Hemiptera/anatomy & histology; Hemiptera/classification*; Hemiptera/growth & development
A new gall-inducing genus and species of felt scales (Hemiptera: Coccoidea: Eriococcidae) found on the leaves and twigs of Matayba guianensis (Sapindaceae) in Brazil is described: Bystracoccus Hodgson gen n. and B. mataybae Hodgson, Isaias & Oliveira sp. n. This is the first record of an eriococcid inducing leaf and stem galls on Sapindaceae and is only the second example of a member of the Eriococcidae to induce stem galls in which the insects diapause during the dry (winter) season. Only the adult female, second-instar female and crawler are known. The species overwinters as the first-instar nymph in pit galls on the twigs but spends the rest of the year associated with two-chambered galls on the leaves. It has recently become clear that South America has a rich felt-scale insect fauna many of which induce galls. It has proved very difficult to place this new genus in a family as it appears to fall between the Eriococcidae and Beesoniidae but is here placed in the eriococcids based on the similarity of the first-instar nymphs and the abundance of this family in the Neotropics. However, the dorsum of the abdomen of the mature adult female becomes heavily sclerotised, forming a round plug-like structure that completely fills the gall orifice. This structure shows remarkable morphological similarities to that of the beesoniid Danumococcus parashoreae Takagi & Hodgson found on Parashorea tomentella (Dipterocarpaceae) in Sabah, Malaysia, with which it is compared along with other eriococcid genera known from South America.
Matched MeSH terms: Hemiptera/anatomy & histology; Hemiptera/classification*; Hemiptera/growth & development
The leafhopper genus Dusuna Distant is revised to include seven species including one new species D. anacantha sp. nov. from China and one new combination D. distanti (Schmidt) n. comb. All species are described and illustrated. A checklist to species of the genus is provided together with a key to separate the two species known from the male. Figures of an unknown species from Malaysia (possibly new) are also included.
Matched MeSH terms: Hemiptera/anatomy & histology; Hemiptera/classification*; Hemiptera/growth & development
An experiment was conducted in Field Laboratory, Department of Entomology at Bangladesh Agricultural University, Mymensingh, during 2013 to manage the mango hopper, Idioscopus clypealis L, using three chemical insecticides, Imidacloprid (0.3%), Endosulfan (0.5%), and Cypermethrin (0.4%), and natural Neem oil (3%) with three replications of each. All the treatments were significantly effective in managing mango hopper in comparison to the control. Imidacloprid showed the highest efficacy in percentage of reduction of hopper population (92.50 ± 9.02) at 72 hours after treatment in case of 2nd spray. It also showed the highest overall percentage of reduction (88.59 ± 8.64) of hopper population and less toxicity to natural enemies including green ant, spider, and lacewing of mango hopper. In case of biopesticide, azadirachtin based Neem oil was found effective against mango hopper as 48.35, 60.15, and 56.54% reduction after 24, 72, and 168 hours of spraying, respectively, which was comparable with Cypermethrin as there was no statistically significant difference after 168 hours of spray. Natural enemies were also higher after 1st and 2nd spray in case of Neem oil.
All life stages (adult female and male, first-instar nymph, second-instar male and female nymphs, and prepupa and pupa) of a new species of Asterolecaniidae, Bambusaspis transversa Lagowska & Martin sp. n., from bamboo in Malaysia, are described and illustrated. The adult female and first-instar nymphs are compared with those Bambusaspis species considered to be closest to the new species.