Gerald R. Carner

Nucleotide sequences of segments 1, 3 and 4 of the genome of Bombyx mori cypovirus 1 encoding putative capsid proteins VP1, VP3 and VP4, respectively

The complete nucleotide sequences of genomic segments S1, S3 and S4 from Bombyx mori cypovirus 1 (BmCPV-1) have been determined. The segments consisted of 4190, 3846 and 3262 nucleotides encoding putative proteins of 1333, 1239 and 1058 amino acids with molecular masses of approximately 148, 140 and 120 kDa (p148, p140 and p120, respectively). All segments possess a single open reading frame. Homology searches showed that all three proteins have homologies to proteins of Rice ragged stunt virus, a member of the genus Oryzavirus within the family REOVIRIDAE: Partial homologies of p140 to structural proteins in other viruses were also found. The predicted molecular masses and the homologies with structural proteins in other viruses lead us to suggest that S1, S3 and S4 encode the capsid proteins VP1, VP3, and VP4, respectively, of BmCPV-1.

First Report of the Papaya Mealybug, Paracoccus marginatus (Hemiptera: Pseudococcidae), in Indonesia and India

Abstract The papaya mealybug, Paracoccus marginatus Williams and Granara de Willink (Hemiptera: Pseudococcidae), is recorded from the Oriental Region for the first time, where it was found in Indonesia (Java) and India (Tamil Nadu) in 2008. Papaya mealybug is a polyphagous pest that damages many tropical crops. A native of Central America, it spread to the Caribbean region and South America in the 1990s; since then it has been accidentally introduced to some islands in the Pacific region. The distribution, host range and characteristics of the mealybug are summarized.

Comparison of the amino acid sequences of RNA-dependent RNA polymerases of cypoviruses in the family Reoviridae

Summary. The nucleotide sequences of the genome segment S2 of Bombyx mori cypovirus 1, S2 of Lymantria dispar cypovirus 1, S1 of Lymantria dispar cypovirus 14 and S1 of a proposed new electropherotype of Trichoplusia ni cypovirus 15 were determined. These segments encoded putative RNA-dependent RNA polymerases (RDRPs). The deduced amino acid sequences of RDRPs within the genus Cypovirus showed 32% to 94% identities, while extent of homology between RDRPs in the genera Cypovirus and Oryzavirus, a genus most closely related, was approximately 26% identity. Both the genera Cypovirus and Oryzavirus might have originated from a common insect virus ancestor.

A new ascovirus from Spodoptera exigua and its relatedness to the isolate from Spodoptera frugiperda

A new ascovirus was isolated from Spodoptera exigua in Indonesia and was tentatively assigned as a new species, Spodoptera exigua ascovirus 5a (SeAV-5a) according to the present ICTV ascovirus naming scheme based on DNA restriction fragment length polymorphism (RFLP), hybridization, formation of occlusion body, tissue tropism and host spectrum. SeAV-5a replicated primarily in the fat body of susceptible hosts. SeAV-5a could be transmitted to S. frugiperda, Pseudoplusia includens and Trichoplusia ni, but not to Heliothis virescens. Infection with SeAV-5a arrested growth of the hosts, but prolonged their survival, which continued up to 33 days. Clusters of virions were seen inside the characteristic vesicles. Occasionally, virions were contained within vacuoles (one to five per vacuole) and some virions were embedded in occlusion bodies. The size of the SeAV-5a virion was 347x134 nm; however, aberrant long secondary viral products were also seen. The presence of occlusion body and Southern hybridization and Western immunoblot analyses suggest that SeAV-5a is more closely related to S. frugiperda ascovirus 1a (SfAV-1a) than to Trichoplusia ni ascovirus 2 (TnAV-2). Certain regions of the 182 kb genome of SeAV-5a showed hybridization to that of SfAV-1a. Two fragments in each of the SfAV-1a ECO:RI and HINdIII digests hybridized to the SeAV-5a genomic DNA probe. Five to eight HINdIII and ECORI fragments in SeAV-5a DNA hybridized to the SfAV-1a genomic probe.

Polyhedrin sequence determines the tetrahedral shape of occlusion bodies in Thysanoplusia orichalcea single-nucleocapsid nucleopolyhedrovirus

A nucleopolyhedrovirus (NPV) isolated from the looper Thysanoplusia orichalcea L. (Lepidoptera: Noctuidae) (ThorNPV) is occluded in a tetrahedral protein matrix. The ORF of the ThorNPV polyhedrin gene contains 738 nt which code for 246 amino acids of the putative polyhedrin protein with an estimated molecular mass of 28,778 Da. The promoter of this gene is similar in length to the promoter of Spodoptera frugiperda NPV (SfMNPV), with a 5 nt deletion before the start codon compared to those of other NPVs. When the polyhedrin gene of Autographa californica NPV (AcMNPV), whose occlusion bodies (OBs) are polyhedral, was replaced by the polyhedrin gene of ThorNPV, which produces tetrahedral OBs, tetrahedral polyhedra with properly occluded virions were produced. This work establishes the importance of the polyhedrin protein sequence in determining OB shape. Leucine at position 43 of ThorNPV polyhedrin was identified as responsible for the tetrahedral shape of ThorNPV OBs by PCR-based site-directed mutagenesis. Susceptibility to alkaline buffer of OBs formed by recombinant AcMNPV (RECAcV) carrying the polyhedrin gene of ThorNPV was slightly greater than that of native ThorNPV OBs. The LD50 of RECAcV for third-instar beet armyworm (Spodoptera exigua) was significantly lower than that of AcMNPV (253 and 31 OBs per larva, respectively).

Microsporidioses of coleopterous pests of soybeans

Interest in insects affecting soybeans has risen sharply in recent years with the increased economic importance of the crop. Among the coleopterous pests, the Mexican bean beetle, Epilachna varivestis, and the bean leaf beetle, Cerotoma trifurcata, are two of the most important defoliators of soybeans (L. L. Dietz, J. W. Van Duyn, J. R. Bradley, R. L. Rabb, W. M. Brooks, and R. E. Stinner, N.C. Agr. Exp. Sta. Tech. Bull. 238, l-264, 1976). Along with several species of lepidopterous defoliators, these pests have received much attention in studies on various strategies and control tactics of soybean insect pests. While much work has been accomplished on pathogens of lepidopterous pests, relatively little is known of the pathogens of the coleopterous pests of soybeans (Dietz et al., lot. cit.). Evidence of a microsporidiosis of E. varivestis was discovered in laboratory colonies being maintained for research purposes at Clemson University in South Carolina and subsequently at North Carolina State University in North Carolina. The microsporidium was a serious limiting factor in maintaining not only the E. varivestis colony but also in producing the larval parasite Pediobius foveolatus for inundative release studies. Incidence of infection in the colonies approached lOO%, and the colonies were gradually decimated by the microsporidian infection. A microsporidium-free culture of E. varivestis was finally obtained by the use of the Pasteur technique involving the selection of egg masses from field-collected, diseasefree female adults. In obtaining data on the prevalence of infection in laboratory and natural populations of E. varivestis and other coleopterous pests, we soon discovered that a second species was also present in E. varivestis and that a third species was present in natural populations of C. trifurcata. Because of their frequent occurrence in laboratory colonies and the economic importance of their hosts as pests of soybeans, brief descriptions of each of these species and their host-pathogen relationships as presently known are presented to assist other workers who might encounter these pathogens in their studies with E. varivestis or C. trifurcata. Since only limited systematic studies have been undertaken so far, these microsporidia will be referred to as MBB (mexican bean beetle) sp. No. 1, MBB sp. No. 2, & BLB (bean leaf beetle) sp. No. 1. We are proceeding on the basis that these are likely new and undescribed species of microsporidia since there are relatively few described species from the Coleoptera in general and no previous reports of microsporidia specifically from E. varivestis or C. trifurcata (V. Sprague, In “Comparative Pathobiology” L. A. Bulla and T. C. Cheng, eds., Vol. 2, pp. l-510, Plenum, New York, 1977). MBB sp. No. 1. Fresh spores (Fig. IA) are straight to slightly curved and ovocylindrical in shape. They measure about 5.3 t 0.13 x 2.1 2 0.03 pm (n = 25) with a mean polar filament length of 84 pm (n = 10). Infection in E. varivestis is generally systemic in nature with the fat body, muscles, and Malpighian tubules being the more heavily invaded tissues. Larvae and adults are easily infected per OS and the microsporidium is also transmitted transovarially at a high incidence. The species is also moderately virulent for larvae of the corn earworm, Heliothis zea, where infection is generally accompanied by an inflammatory response including extensive cellular infiltration by hemocytes and melanization.

Comparative Infectivity of Homologous and Heterologous Nucleopolyhedroviruses against Beet Armyworm Larvae1

ABSTRACT  Homologous and heterologous nucleopolyhedroviruses (NPVs) were assayed to determine their effectiveness against beet armyworm larvae, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae). Included were three NPV isolates from S. exigua, one isolate each from S. littoralis Boisduval, S. litura (F.), and S. ornithogalli (Guenée), two isolates from other noctuids, Helicoverpa armigera (Hübner) and Rachiplusia ou (Guenée), and one isolate from Plutella xylostella (L.) (Lepidoptera: Plutellidae). Before bioassays, all of the NPVs were serially passed four times through S. exigua larvae to increase their concentrations. The narrow host-range homologous SeMNPVs from South Carolina (SeMNPV-SC), Maryland (SeMNPV-MD), and Florida (SeMNPV-FL  =  Spod-X®) were three of the most effective NPVs against the homologous host, S. exigua, based on median lethal concentration values (LC50). Three heterologous isolates (HearNPV from H. armigera, SpliNPV from S. littoralis, and RoMNPV from R. ou) also had low LC50 values. According to their LC50 values, the least active NPVs were from P. xylostella (PlxyMNPV), S. ornithogalli (SoNPV), and S. litura (SpltNPV). Based on median time to kill (LT50) at LC90 concentrations, SeMNPV-SC and Spod-X® were the most effective isolates. The slowest acting NPVs were from S. litura, S. littoralis, and S. ornithogalli. The virulence of homologous and heterologous NPVs did not appear to be correlated with their genomic relatedness to SeMNPV or to the relatedness of the original NPV insect hosts to S. exigua.

Aspidiotus rigidus Reyne (Hemiptera: Diaspididae): a devastating pest of coconut in the Philippines

The Philippines is the second largest producer of coconut products and, in some areas, coconut farming is the main source of livelihood. A damaging armoured scale insect (Hemiptera: Diaspididae) infesting coconut palms was first found in the Philippines on Luzon Island (Batangas province) in 2009, and is now affecting most of the provinces of southern Luzon. The scale pest is still spreading in the Visayan Islands and Mindanao. Infestation stops photosynthesis; the leaves yellow and dry; fruits form less nutmeat and the coconut‐water is sour; weak new leaflets bend over or break off; and the tree dies in 6 months or less. The scale pest is identified in the present study as Aspidiotus rigidus Reyne; it presents a significant quarantine threat to coconut‐producing countries worldwide. Characters enabling the identification of A. rigidus, its host range and distribution are given. Some literature on the natural enemies and control of A. rigidus is reviewed briefly.

Sap-sucking insect records (Hemiptera: Sternorrhyncha and Thysanoptera: Thripidae) from Indonesia.

Abstract Sap-sucking insects (Hemiptera: Sternorrhyncha and Thysanoptera: Thripidae) collected in Java, Sumatra and Sulawesi were identified. From 28 samples collected on 9 crop and ornamental host-plant species, 21 species of sap-sucking insects were identified, 12 (57%) of which were new island distribution records. This suggests that the Indonesian insect fauna has not been documented for a long time. The new distribution records are: from Java, Lepidosaphes gloverii (Packard) (Diaspididae); from Sumatra, Clavaspidiotus apicalis Takagi (Diaspididae); and from Sulawesi, Coccus hesperidum L. (Coccidae), Saissetia coffeae (Walker) (Coccidae), Aulacaspis yasumatsui Takagi (Diaspididae), Hemiberlesia palmae (Cockerell) (Diaspididae), Lepidosaphes tokionis (Kuwana) (Diaspididae), Microparlatoria fici (Takahashi) (Diaspididae), Pseudaulacaspis cockerelli (Cooley) (Diaspididae), Icerya aegyptiaca (Douglas) (Monophlebidae), I. pulchra (Leonardi) (Monophlebidae) and Selenothrips rubrocinctus (Giard) (Thripidae). Clavaspidiotus apicalis could become a potentially invasive pest of citrus.