Development of a framework for internet based education system

Development of a framework for Internet based education has demonstrated the use of Oracle tools for the use of delivery of education on the World Wide Web. This also has proved that for an efficient dynamic education scenario, the use of a database-based system with a proper retrieval system is required. We have designed the system on an Oracle backend system with Designer/2000. Developer/2000 helped us with the design and development of the system. Oracle Web Server 2.1 helped us with the retrieval of the web pages. The entire design of the system and the reasoning behind the system has been documented. Appendix A provides a glossary of currently used terminology in the field of Internet based systems. The Appendix B provides actual screen prints of the Designer/2000 phases of design, Developer/2000 graphical user interface screens and the actual code involved in the design and development of the system. The fact that the entire system is based on the Oracle Repository makes the system very dynamic in terms of the data and can be used to present the student with a course material rapidly

Incorporating neonicotinoid and anthranilic diamide insecticides into integrated pest management of rice water weevil, Lissorhoptrus oryzophilus

Seed treatments with chlorantraniliprole and thiamethoxam have been used for the management of rice water weevil, Lissorhoptrus oryzophilus in the United States. Both insecticides being plant-systemic could potentially target multiple life stages of L. oryzophilus. The rational use of these chemicals as seed treatments in weevil management requires thorough understanding on targeted life stages of L.oryzophilus and, the relative persistence and potency of both chemicals. A series of greenhouse and laboratory experiments were conducted on weevils by culturing rice plants treated as seeds with different rates of chlorantraniliprole and thiamethoxam. Adult feeding assays on foliage from treated plants revealed divergent effects: treatments with thiamethoxam but not chlorantraniliprole affected adult mortality and foliar consumption. Dose-mortality relationships for thiamethoxam were determined by combining the estimates of leaf biomass consumed by weevils in conjunction with foliar insecticide residues estimated by LC/MS/MS. The LD50 s obtained were the first LD50 s in leaf feeding insects feeding on foliage of thiamethoxam-treated plants. Changes in adulticidal activity with plant-growth were related to the residues analyzed by ELISA method. Adult exposure to treated rice (6-7 leaf stage) led to reduced egg numbers and first instar emergence. The low egg numbers by adults in chlorantraniliprole was confirmed as a sub-lethal effect: survival was not impacted on foliage but the number of eggs by adults was reduced when released on untreated plants. Furthermore, a comparison of first instar emergence from chlorantraniliprole-treated plants and from untreated plants infested with weevils previously exposed to this chemical suggested that chlorantraniliprole was also reducing egg or first instar survival. Sub-lethal effects of thiamethoxam on weevils that survived feeding exposure were manifested in reduced egg numbers. Finally, differential activities of both seed treatments on weevil life stages were related to residue patterns in plant portions. In chlorantraniliprole, the greatest reduction occurred in late instars feeding on roots, whereas in thiamethoxam, reduction was largely due to disrupted adult survival and egg-laying. High above ground concentrations of thiamethoxam and high below ground concentrations of chlorantraniliprole in rice plants were consistent with differential activities. The implications of such divergent distribution patterns on L.oryzophilus management were discussed

Comparison of the Effects of Neonicotinoids and Pyrethroids Against Oebalus pugnax (Hemiptera: Pentatomidae) in Rice

The rice stink bug, Oebalus pugnax (F.) (Hemiptera: Pentatomidae), is an economically important late-season pest of rice in the southern United States. Stink bug feeding results in yield reduction and discounted purchase price due to broken or discolored ( pecky ) rice grains. The primary tactic for O. pugnax management is the application of insecticides once adults reach an action threshold. Recent surveys show that pyrethroids are preferred by southern U.S. rice farmers over all other insecticides to reduce O. pugnax densities. However, preliminary tests in 2009 suggested resistance to pyrethroids may be developing in an O. pugnax population in Texas, where applications are more frequent than in other rice-growing areas. This study compared the effects of pyrethroids and neonicotinoids on O. pugnax behavior and mortality in the laboratory and in a number of field experiments conducted between 2011 and 2014. Results from these experiments showed that control of O. pugnax given by the neonicotinoid, dinotefuran, was similar to that given by pyrethroids in the laboratory and field. Results from small-plot field studies were influenced by movement of adult rice stink bugs from surrounding untreated plots, and the data from commercial-scale trials and from sampling of nymphs in small plots may provide more useful information on the efficacies of insecticides. Two experiments provided limited evidence for longer residual activity of dinotefuran compared to the pyrethroid-cyhalothrin, and a laboratory study showed that both insecticides reduced feeding activity of rice stink bugs. Tests also confirmed the increased tolerance of a Texas population of rice stink bugs to-cyhalothrin, suggesting the need for insecticides with different modes of action in the O. pugnax management program

Influence of Rice Seeding Rate on Efficacies of Neonicotinoid and Anthranilic Diamide Seed Treatments against Rice Water Weevil

Rice in the U.S. is frequently seeded at low rates and treated before sowing with neonicotinoid or anthranilic diamide insecticides to target the rice water weevil. A previous study of the influence of seeding rate on rice water weevil densities showed an inverse relationship between seeding rates and immature weevil densities. This study investigated interactive effects of seeding rate and seed treatment on weevil densities and rice yields; in particular, experiments were designed to determine whether seed treatments were less effective at low seeding rates. Four experiments were conducted over three years by varying seeding rates of rice treated at constant per seed rates of insecticide. Larval suppression by chlorantraniliprole was superior to thiamethoxam or clothianidin, and infestations at low seeding rates were up to 47% higher than at high seeding rates. Little evidence was found for the hypothesis that seed treatments are less effective at low seeding rates; in only one of four experiments was the reduction in weevil densities by thiamethoxam greater at high than at low seeding rates. However, suppression of larvae by neonicotinoid seed treatments in plots seeded at low rates was generally poor, and caution must be exercised when using the neonicotioids at low seeding rates

The use of systemic anthranilic diamide and neonicotinoid seed treatments in rice pest management

© 2014 American Chemical Society. The rice water weevil, Lissorhoptrus oryzophilus, is the key insect pest of rice in the United States. Over the last five years, anthranilic diamide and neonicotinoid seed treatments have been introduced into the U.S. rice market for management of rice water weevils and other early and mid-season pests. This chapter reviews several aspects of the use of seed treatments in rice. In a four-year field study involving over 40 commercial fields throughout Louisiana, threshold densities of rice water weevil larvae were exceeded in over 80% of untreated fields. Seed treatments of thiamethoxam, a neonicotinoid, were about as effective as foliar applications of pyrethroids at reducing densities of rice water weevil larvae in commercial fields, while seed treatments containing chlorantraniliprole were significantly more effective than pyrethroids or thiamethoxam. A series of greenhouse studies demonstrated that seed treatments of chlorantraniliprole and thiamethoxam have differential effects on life stages of the rice water weevil. Seed treatment with thiamethoxam reduced survival of adults feeding on leaves of treated plants, and had pronounced effects on egg-laying and early instar survival; chlorantraniliprole seed treatment, in contrast, had no effects on adults and exerted its effects primarily on root-feeding larvae. These differences in biological activities were consistent with patterns of distribution of insecticides in tissues of treated plants: high concentrations of chlorantraniliprole were found in roots of both greenhouse and field-grown plants, while thiamethoxam concentrations were higher in above-ground portions of plants. The greater efficacy of chlorantraniliprole seed treatment in field experiments is probably attributable to the greater persistence of this chemical in rice plants and to the tendency of this chemical to accumulate in root tissues. Standard and reduced rates of chlorantraniliprole seed treatment were compatible with two alternative management practices, shallow flooding and plant resistance, in a small-plot field study. Chlorantraniliprole and neonicotinoid seed treatments had differential effects on other pests of rice, including the fall armyworm, Spodoptera frugiperda and sugarcane borer, Diatrea saccharalis. The ubiquity and severity of the rice water weevil as a pest, the effectiveness of seed treatments against both the rice water weevil and sporadic pests, and the lower impact of seed treatments on key non-target organisms provide solid justification for the use of seed treatments in rice

Integrating flood depth and plant resistance with chlorantraniliprole seed treatments for management of rice water weevil, Lissorhoptrus oryzophilus (Coleoptera: Curculionidae)

© 2014 Institute of Zoology, Chinese Academy of Sciences. Chlorantraniliprole seed treatments in rice provide effective suppression of rice water weevil populations in the United States; however, heavy reliance on prophylactic insecticide treatments as a sole strategy could destabilize management programs for this insect. The present research evaluated the compatibility of seed treatments with two other potential management tactics-plant resistance and shallow flooding-by conducting two split-plot experiments in 2009 and 2011. In both experiments, no substantial antagonism was found among the 3 different tactics. Statistical interactions in these experiments arose from the strong and persistent effects of chlorantraniliprole on larval densities rather than incompatibility of tactics. In 2009, weevil densities differed among varieties and were significantly lower on the cultivar Jefferson. In 2011, weevil densities were reduced significantly in shallow-flooded plots compared to deep-flooded plots. Significant reductions in weevil numbers by chlorantraniliprole seed treatments, even at application rates 5 fold lower than commercially recommended rates, demonstrated the potential to reduce application rates of this highly potent larvicide. These latter results suggest that future studies on the relationship between chlorantraniliprole seed treatment rate and weevil fitness are warranted

Evaluation of neonicotinoids as pyrethroid alternatives for rice water weevil management in water-seeded rice

The rice water weevil (RWW), Lissorhoptrus oryzophilus (Kuschel) (Coleoptera: Curculionidae), is the most destructive insect pest of rice in the United States. Water-seeded rice, which is flooded at an earlier stage of crop development than drill-seeded rice, is at heightened risk of loss from root-feeding RWW larvae. Pyrethroids, the most widely used group of foliar insecticides for RWW control, have inherent limitations such as limited residual activity, narrow window of activity and extreme toxicity to non-target aquatic organisms. An array of field, lab and greenhouse experiments was conducted to compare the activity of two neonicotinoids with that of λ-cyhalothrin, a widely used pyrethroid, against the RWW. Small-plot efficacy trials were conducted during 2009, 2010 and 2011. Foliar clothianidin (Belay 2.13 SC) and a granular formulation (3%) of dinotefuran applied to plots were as effective as, and showed greater residual activity than, foliar applications of λ-cyhalothrin. Topical bioassays on adult weevils revealed that clothianidin possessed lower contact toxicity than λ-cyhalothrin. Residual assays using weevils placed on foliage of sprayed plots revealed that the toxic and sublethal behavioral effects of clothianidian on adult weevils were more persistent for clothianidin than for λ-cyhalothrin. Granular dinotefuran applied to greenhouse-grown plants previously infested with weevil larvae showed excellent larvicidal activity. Overall, these studies showed that neonicotinoids have potential as pyrethroid replacements against the RWW in water-seeded rice culture. © 2013 Elsevier Ltd

Evaluation of Residual Efficacy of Pyrethrin + Methoprene Aerosol on Two Dermestids: Impact of Particle Size, Species, and Temperature

Residual effects of pyrethrin + methoprene aerosol dispensed at 4 and 16-µm particle sizes and an untreated control, was assessed against late-stage larvae of Trogoderma inclusum (LeConte), the larger cabinet beetle, and T. variabile (Ballion), the warehouse beetle. Treated arenas were stored at 25, 30, 35, and 40 °C and bioassays were conducted at 1, 3, or 6 weeks post-treatment. Larval development was monitored through adult emergence to compare the efficacy of treatments by using both the percentage of normal adult emergence and a developmental index as dependent variables. There was no overall effect of temperature on residual activity as measured using either adult emergence or developmental index values. Both the 4 and 16-µm particle sizes resulted in reduced adult emergence and low developmental index values compared to untreated controls. The insecticide was more effective on T. variabile than on T. inclusum. The impact of particle size varied between species, both particle sizes reduced adult emergence and developmental index in T. variabile, but only the 16-µm particle size resulted in reduction of adult emergence of T. inclusum. Furthermore, there was a reduction in activity of methoprene with residual exposure time. The variations in susceptibility of species to methoprene, differences in efficacy of particle sizes, and decrease in residual persistence at smaller particle sizes highlight the need for attaining optimal particle size to improve overall efficacy of aerosol mixtures containing methoprene

Activity of chlorantraniliprole and thiamethoxam seed treatments on life stages of the rice water weevil as affected by the distribution of insecticides in rice plants

BACKGROUND: The systemic insecticides chlorantraniliprole (CAP) and thiamethoxam (TMX), applied to rice as seed treatments, may affect multiple life stages of the rice water weevil, Lissorhoptrus oryzophilus. Effects of CAP and TMX on adult survival, egg-laying and first- and late-instar survivals were determined by infesting plants treated as seeds with different rates of insecticides. The biological activity was related to insecticidal concentrations in leaves, shoots and roots. RESULTS: CAP did not affect adult survival but decreased egg numbers and reduced the survival of the first and late instars. The greatest reduction in weevil population occurred in late instars feeding on roots. In contrast, TMX reduced adult survival and egg and larval numbers. The high biological activity of CAP on root-feeding stages was consistent with the accumulation of CAP in roots, whereas in TMX-treated plants the high activity on adults correlated with high concentrations of TMX in leaves and stems. CONCLUSIONS: The differential activity of insecticides on adults suggests poor inherent potency of CAP as an adulticide and/or its limited systemicity in foliage. The distribution of insecticide in specific plant parts can be attributed to the different physicochemical properties of CAP and TMX. The field implications of this research on management of L. oryzophilus are discussed. © 2013 Society of Chemical Industry

Acute toxicity of chlorantraniliprole to non-target crayfish (Procambarus clarkii) associated with rice-crayfish cropping systems

Background: Chlorantraniliprole, a novel anthranilic diamide insecticide, was recently introduced into the United States where rice-crayfish crop rotations are practiced to control rice water weevil (Lissorhoptrus oryzophilus Kuschel) infestations. Chlorantraniliprole has high margins of mammalian safety and excellent insecticidal efficacy, but its toxicity to non-target crayfish is uncertain. In this study, the acute toxicity of chlorantraniliprole to the red swamp crayfish Procambarus clarkii Girard was determined using aquatic and feeding assays. Results: The aquatic 96 h median lethal toxicity (LC50) data indicate that technical-grade chlorantraniliprole is highly toxic (US EPA category) to crayfish with an LC50 of 951 μg L-1 (95% CL = 741-1118μg L-1). A no observed effect concentration (NOEC) of 480 (ig L-1 was recorded. Neither the 36 day chronic feeding study, where crayfish fed on chlorantraniliprole-treated rice seed in aquaria, nor the 144 h acute feeding test, where crayfish fed on rice seeds treated with chlorantraniliprole, produced mortality or abnormal behavior. Conclusion: Chlorantraniliprole is three orders of magnitude less acutely toxic to P. clarkii than lambda-cyhalothrin and etofenprox, two pyrethroid insecticides also used in rice, and is less likely to cause acute crayfish toxicity in rice pond ecosystems. Based on acute toxicity data, the use of chlorantraniliprole should be more compatible with rice-crayfish crop rotations than pyrethroids. © 2010 Society of Chemical Industry