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1.
Field studies in soybeans have demonstrated that the endemic predator, Orius insidiosus (Say), is an important natural enemy of the soybean aphid, Aphis glycines Matsumura. Soybean thrips, Neohydatothrips variabilis (Beach), serve as an important prey resource for O. insidiosus in soybeans and may be important in sustaining O. insidiosus populations before the arrival of soybean aphid. Because soybean aphid is new to the US soybean system, the effects of a mixed diet of soybean aphid and soybean thrips on O. insidiosus life history is not known. We measured the survival, development, and reproduction of O. insidiosus when fed soybean thrips, and a mixed prey diet of soybean aphids and soybean thrips, and compared these results to a previous study of O. insidiosus life history fed soybean aphid alone. Nymphal development to adulthood (15.9 days) and fecundity (68.8 eggs per female) was improved for O. insidiosus fed ad libitum soybean thrips daily compared to O. insidiosus fed ad libitum soybean aphids daily. The contribution of alternative prey to O. insidiosus life history characteristics can be complex depending on the amount and quality of a particular prey item. At low levels of prey, the addition of prey appears to enhance O. insidiosus survival, development, and fecundity. However, as predators are fed more often, the predator’s response depends on the type of prey that predominates in the mixed prey diet. We discuss soybean thrips impact on O. insidiosus population ecology and soybean aphid dynamics.  相似文献   

2.
Gut bacteria play a crucial role in the several metabolic activity of the insects. In the present work, effort has been made to decipher the gut microbiota associated with the developmental stages of Gynaikothrips uzeli a gall inducing thrips along with their predicted functional role. Further, an effort has been made to correlate the bacterial communities with plant pathogenesis and thelytoky behaviour of G. uzeli. Findings obtained revealed that genus Arsenophonus dominated the total bacterial diversity and was transmitted vertically through the developmental stages. Further, it was observed that the high abundance of genus Arsenophonus promotes the thelytoky behaviour in G. uzeli and results in the killing of males. Furthermore, strong connecting link between Arsenophonus abundance and gall induction in F. benjamina was observed in the current dataset. G. uzeli being in the category of phloem sucking insect was known for the induction of galls and the current findings for the first time unveiled the facts that high abundance of genus Arsenophonus a well-known plant pathogen may be one of the major reason for inducing galls in F. benjamina. Moreover, PICRUSt2 analysis revealed that predicted functional pathways like biosynthesis of amino acids, and metabolism of carbon, nitrogen, carbohydrates and amino acids (e.g. Arginine, Alanine, Aspartate, Glutamate, Proline, Cysteine, Methionine, Glycine, Threonine, and Serine) were frequently noticed in profiles associated with all the developmental stages of G. uzeli. More to this, the high abundance of Arsenophonus in G. uzeli suggest that representatives of this genus may be resistant and/or tolerant to different antibacterial agents, alkaloids, flavonoids, and glycosides (e.g. quercetin). The correlation of bacterial diversity in pathogenicity can be extrapolated in different pest and vector species of other arthropods.  相似文献   

3.
A water-insoluble polysaccharide (PCS3-II) extracted from sclerotium of Poria cocos was identified as a linear (1  3)-β-d-glucan by 13C NMR and gas chromatography. Aqueous 0.5 M NaOH/0.2 M urea was a good solvent for PCS3-II and the dependence of intrinsic viscosity ([η]) on weight-average molecular weight (Mw) was established in the Mw range from 7.68 × 104 to 5.14 × 105 to be [η] = 3.39 × 10?2 MW0.62cm3g-1 at 25 °C by using laser light scattering and viscometry. The chain conformation parameters of PCS3-II in the 0.5 M NaOH/0.2 M urea solution was 2.3 (± 0.3) nm for persistence length (q), 580 g mol?1 nm?1 for molar mass per unit contour length (ML), 0.8 (± 0.2) nm for the diameter of the chain (d) and 3.63 for limited characteristic ratio (C). The results revealed, for the first time, that PCS3-II existed as a flexible chain in 0.5 M NaOH/0.2 M urea aqueous solution.  相似文献   

4.
Potato psyllid, Bactericera cockerelli, is a serious pest of potato and other solanaceous vegetables in the United States, Mexico, Central America, and New Zealand and is responsible for transmission of Candidatus Liberibacter solanacearum which causes a disease known as “zebra chip” (ZC). Entomopathogenic fungi could provide a viable component for an integrated pest management strategy for control of B. cockerelli and other potato pest insects. Three field trials of commercial formulations of Metarhizium anisopliae (F 52®, Novozymes Biologicals) and Isaria fumosorosea (Pfr 97®, Certis USA) and abamectin (Agri-Mek®, Syngenta, USA) were conducted in Weslaco, Texas. Rates are expressed in quantity of product delivered in 375–470 l of water/ha. F 52 applied at 0.51, 1.1, and 2.2 l/ha and Agri-Mek applied at 584 ml/ha produced reductions of B. cockerelli eggs and nymphs of 45%, 59%, 67%, and 63%, respectively. Only Agri-Mek significantly reduced plant damage. Pfr 97 at 1.1 kg/ha with and without 1% Trilogy® (neem oil, Certis, USA), and Agri-Mek at 584 ml/ha resulted in psyllid reductions of 78%, 76%, and 84%, respectively. Significantly decreased plant damage and ZC symptoms were observed for all treatments. Tuber yields for Pfr plus Trilogy and Agri-Mek were significantly higher than the control. F 52 applied at 1.1 and 2.2 l/ha and Pfr 97 at 1.1 and 2.2 kg/ha produced 62%, 62%, 66%, and 65% reduction, respectively. Tuber yield for both rates of Pfr and the high rate of F 52 were significantly higher than the control. All fungal treatments significantly reduced plant damage and ZC symptoms.  相似文献   

5.
The predatory bugsOrius insidiosus andOrius albidipennis are potential candidates for biocontrol of the thrips,Frankliniella occidentalis. Laboratory experiments showed thatO. albidipennis lays significantly more eggs thanO. insidiosus while its life cycle is shorter. As more eggs are laid byO. albidipennis in the beginning of the oviposition cycle, this anthocorid may be considered as the better biocontrol agent.  相似文献   

6.
Human cystic echinococcosis is a highly endemic zoonotic disease in the province of Neuquén, Patagonia Argentina, although a hydatid control programme has been carried out since 1970. Human infection due to Echinococcus canadensis (G6 genotype) is frequent in Neuquén. However, the reservoir for this species remains undetermined in a region where camels are absent. We investigated the fertility, viability and molecular epidemiology of hydatid cysts obtained from local goats, pigs and sheep in order to identify the possible reservoirs of E. canadensis (G6). We also analyzed isolates from infected dogs. A total of 67 isolates were identified by the DNA sequencing of the mitochondrial cytochrome c oxidase subunit 1 gene. Cysts from sheep (n = 16), goats (n = 23) and pigs (n = 18) and adult worms from 10 infected dogs were analyzed. The fertility of the hydatid cysts was 78.6%; 90.4% and 94.4% for sheep, goats and pigs, respectively. We detected E. canadensis (G6) in 21 of 23 goat samples and in 1 dog isolate, E. canadensis (G7) in all the pig isolates, E. granulosus sensu stricto (G3) in 1 sheep and the G1 genotype in 15 sheep, 2 goats and 9 dog samples. The G1 haplotypes included the common sheep strain sequence and 2 microvariants of this sequence. E. granulosus sensu stricto (G3) is described for the first time in South America. We conclude that goats act as reservoir for E. canadensis (G6) in Neuquén, and that control strategies may have to be adapted to local molecular epidemiology to improve the control of parasite transmission.  相似文献   

7.
Plant products along with biocontrol agents were tested against Fusarium wilt of banana caused by Fusarium oxysporum f. sp. cubense (Foc). Of the 22 plant species tested, the leaf extract of Datura metel (10%) showed complete inhibition of the mycelial growth of Foc. Two botanical fungicides, Wanis 20 EC and Damet 50 EC along with selected PGPR strains with known biocontrol activity, Pseudomonas fluorescens 1, Pf1 and Bacillus subtilis, TRC 54 were tested individually and in combination for the management of Fusarium wilt under greenhouse and field conditions. Combined application of botanical formulation and biocontrol agents (Wanis 20 EC + Pf1 + TRC 54) reduced the wilt incidence significantly under greenhouse (64%) and field conditions (75%). Reduction in disease incidence was positively correlated with the induction of defense-related enzymes peroxidase (PO) and polyphenol oxidase (PPO). Three antifungal compounds (two glycosides and one ester) in D. metel were separated and identified using TLC, RP-HPLC (Reverse Phase-High Pressure Liquid Chromatography) and mass spectrometry. In this study it is clear that combined application of botanical formulations and biocontrol agents can be very effective in the management of Fusarium wilt of banana.  相似文献   

8.
Current strategies for marine pollution monitoring are based on the integration of chemical and biological techniques. The sea urchin embryo-larval bioassays are among the biological methods most widely used worldwide. Cryopreservation of early embryos of sea urchins could provide a useful tool to overcome one of the main limitations of such bioassays, the availability of high quality biological material all year round. The present study aimed to determine the suitability of several permeant (dimethyl sulfoxide, Me2SO; propylene glycol, PG; and ethylene glycol, EG) and non-permeant (trehalose, TRE; polyvinylpyrrolidone, PVP) cryoprotectant agents (CPAs) and their combination, for the cryopreservation of eggs and embryos of the sea urchin Paracentrotus lividus. On the basis of the CPAs toxicity, PG and EG, in combination with PVP, seem to be most suitable for the cryopreservation of P. lividus eggs and embryos. Several freezing procedures were also assayed. The most successful freezing regime consisted on cooling from 4 to −12 °C at 1 °C/min, holding for 2 min for seeding, cooling to −20 °C at 0.5 °C/min, and then cooling to −35 °C at 1 °C/min. Maximum normal larvae percentages of 41.5% and 68.5%, and maximum larval growth values of 42.9% and 60.5%, were obtained for frozen fertilized eggs and frozen blastulae, respectively.  相似文献   

9.
Infection by the larval stage of the cestode Echinococcus granulosus causes a disease known as cystic echinococcosis or hydatidosis, which is one of the most widespread zoonotic infections of veterinary and medical importance. Numerous studies have shown that E. granulosus exists as a complex of strains differing in a wide variety of criteria. Ten distinct genotypes (G1–G10) have been identified with a potential impact on the pathology, epidemiology and the effect of the measures implemented for the control of hydatidosis. Our main objective was to carry out a preliminary analysis of the genotypes of E. granulosus circulating in the central inland region of Portugal.Parasite samples (hydatid cysts, n = 27) were isolated from the liver and lung of sheep and cattle. The DNA extracted from protoscoleces isolated from the fertile cysts served as a template for the PCR amplification of the part of the mitochondrial cytochrome c oxidase subunit 1 (cox1), ATP synthase F0 subunit 6 (atp6) as well as the large (rrnL/16 S) and small (rrnS/12 S) ribosomal RNA genes. Similarity searches with homologous sequences in the databanks indicated a very high similarity with references assigned to the G1, G3 and/or G1–G3 complex of Echinococcus strains. Phylogenetic analysis (Bayesian approach) supported these observations, and confirmed the assignment of all the analyzed sequences to the G1–G3 genetic cluster.  相似文献   

10.
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