Evaluating Consequences of an Environmental †Assignmenthelp.com

Question: Discuss about the Evaluating Consequences of an Environmental. Answer: Introduction: Spodoptera frugiperda is the larval stage of the fall armyworm moth and is considered to be a highly dangerous pest for the crops if adequate actions are taken to minimize its multiplication. The species name frugiperda is derived from the Latin word meaning lost or destroyed fruit, and very fittingly with the name, this pest is known to wreck havoc on its host destroying the crop completely. It is considered to be the cosmopolitan pest of the maize crop, and this particular crop feeds on all the growth stages of the host plant; however this pest is most frequently seen in the whorl of the young plants that are up to 45 days old (Hernndez-Rodrguez et al., 2013). The fall armyworm or Spodoptera frugiperda is native to the tropical regions of the Western hemisphere, the demographical origin ranging from United States to the Argentina. The pest can successfully overwinter in the USA, however just in the Southern Florida and Southern Texas. Although, the fall armyworm is a strong flier and easily overcomes long distances during summer months towards all the states that are situated east of the Rocky Mountains. However, the pest is considered as a regular and serious pest in the south-eastern states. Aside from the America, the pest was reported in west and central Africa in 1916 for the first time, it threatens Africa and Europe as well now (Bernardi et al., 2015). The feeding habit of Spodoptera frugiperda consists of mainly small grain crops and grasses, and the host range of the species is up to 80 different species. The most common host for this pest is the sweet corn or maize, and long with that sorghum, bermundagrass are considerable preferences of the pest as well. Along with that the fall armyworm also favours the grass weeds such as crabgrass, Digitaria. The field crop reported with fall armyworm invasion are alfalfa, barley, Bermudagrass, buckwheat, cotton, clover, corn, oat, millet, peanut, rice, ryegrass, sorghum, sugarbeet, Sudangrass, soybean, sugarcane, timothy, tobacco, and wheat. And the vegetable crop hosts of the pest include apple, grape, orange, papaya, peach, strawberry and a number of flowers as well (Bernardi et al., 2015). Biology and ecology of S. Frugiperda: frugiperda are very similar in shape and size to other regular moths belonging to the cutworm family, the moths are greyish in colour and their wingspan is about 1.5 inches. The pest lays eggs in clusters of 50 or more, always in a layer like linear style attached to the foliage, the colour of the eggs are gray and are dome shaped. Scales, grayish in colour are scattered over the egg mass by the female moth giving the egg mass a moldy or hairy appearance. The newly hatched larvae are pale green in appearance and have black coloured heads, and the young larvae feed near the surface of the ground and after about a week they move up to the corn plants and feed on the foliage and leave tissues except the vein and midriff (de Souza Tavares et al., 2013). The fully grown larvae are 1.25 to 1.5 inches long and the body colour vary from pale green to black depending on the stage of maturation, and they have reddish brown heads. Fall armyworms also have inverted Y shaped black tubercles with hairs attached all over arrayed all throughout the body. The pest pupates in the soil and the pupae have smooth leathery appearance and are reddish brown to dark brown in colour. The pests are migratory in nature and their ecological behaviour varies extensively depending on the seasonal factors and their maturation stage (de Souza Tavares et al., 2013). Damages and symptoms: The larvae of the pest S. Frugiperda causes damage to the host plant by consuming. The young larvae initially feed on the leaf tissues on one side, while leaving the opposite side epidermal layer completely intact. As the larvae move toward second or third instar, they start making holes in the leaves and begin feeding inwards from the edge of the leaves, which in turn generates the characteristic row of punctures in the leaves. As the larvae grow older they cause excessive defoliation, leaving out only the ribs and stalks of the corn plants, giving the plant a ragged and torn appearance. The adult moth of Spodoptera frugiperda are very similar to other genera of cutworm, however it can be recognized by the distinct dark veins and the orbicular stigma. In case of the larvae of the S. Frugiperda, the distinctive feature is the Y shaped mark in the top of the head, and the larvae feed both in the day and in the night unlike any other kind of armyworm larvae. The prevalence of the pest and the proximity of the of the host species decide the density of the invasiveness of the pest (Hernndez-Rodrguez et al., 2013). Studies suggest that up to 34% of the yield reduction in the corn yield all through America is due to fall armyworm hence it can be considered that the invasiveness of the pest is considerably high. As S. Frugiperda has cannibalistic feeding habit the larvae density decreases in the whorl feeding stage for the older or adult larvae and the extent of damage escalates. Authors suggest that the relation between the stage of invasion and the reduction in yield follo w a complex mechanism, and different factors like soil fertility, favourable climate and cultivar variety play an important role. However, in the year 2017, the fall armyworm invested extensive corn fields of the southern Africa that indicates at the extreme invasiveness of the pest (Roel et al., 2010). Population Ecology: Life history of S. Frugiperda: The life cycle of S. frugiperda is completed within 30 days in the summer, however during the months spring and autumn, the time frame increases to 80 and 90 days in the winters. The adult moth lays close to 1500 eggs, however the number of eggs varies . The egg stage lasts for only two to three days during the summer upon arrival to the new field (Storer et al., 2010). After the egg stage there are 6 instars, the larvae stage lasts for 14 days for the summer months and 30 days in the winter. Past the maturation stage, the pupation starts normally within the soil, the depth of which ranges between 2 to 8 cm. The cocoon is ranges from 20 to 30 mm in length and the size of the pupa is 14 to 18 mm in length and 4.5 mm in width. The pupal stage extends for 20 to 30 days, however ion case of summer it can be completed within 9 days. The adult moths live for 10 days in average, however it can vary between 7 to 21 days, depending on when the preoviposition and oviposition occurs (Storer et al., 2012). r/K selection theory: There are many management models for the management of the pest a d minimizing the damage that the pest can import on the crops. One of these management tools can be the r/K selection theory. It is widely used for the comparison of the plant pathogen life strategies, in the parasitic phase. Plant pathogens are generally r-selected, however the formula depends on the evolution of the species in two generalized directions. The formula states, in case of NB population, r is the maximum growth rate and K is the carrying capacity of the environment with dN/dt denotes the derivative of N with respect to time t. Fall armyworm is a r selected pathogen (Tavares et al., 2010). Ecologically based plant management: It is basically a decision making framework that allows the cultivator to improve the management of invasive plant species. This management tool has 5 steps, the first step is the range and health assessment, the second step is the identification of the cause of the invasion, the step three is the use of principles to guide the decision making, the fourth step is to choose appropriate tools for the principle strategizing and the fifth stage is the design and the execution of the plan. It can be a potent management tool for the management of fall armyworm for the corn species (von Mrey et al., 2012). Conclusion: In a concluding note, it can be said that fall armyworm is a highly invasive and highly damaging pest species which has known to cause huge yield loss in the years and with the distribution of this species vastly wide spread, every year the pest causes close to 30 % of reduction of yield. The management tools like EBMP and biological and chemical control methods are the potent tool for the pest management of this pest and the restoring the crop yield at a large extent. References: Bernardi, D., Salmeron, E., Horikoshi, R. J., Bernardi, O., Dourado, P. M., Carvalho, R. A., ... Omoto, C. (2015). Cross-resistance between Cry1 proteins in fall armyworm (Spodoptera frugiperda) may affect the durability of current pyramided Bt maize hybrids in Brazil.PLoS One,10(10), e0140130. de Souza Tavares, W., de Sousa Freitas, S., Grazziotti, G. H., Parente, L. M. L., Lio, L. M., Zanuncio, J. C. (2013). Ar-turmerone from Curcuma longa (Zingiberaceae) rhizomes and effects on Sitophilus zeamais (Coleoptera: Curculionidae) and Spodoptera frugiperda (Lepidoptera: Noctuidae).Industrial crops and products,46, 158-164. Desneux, N., Ramrez-Romero, R., Bokonon-Ganta, A. H., Bernal, J. S. (2010). Attraction of the parasitoid Cotesia marginiventris to host (Spodoptera frugiperda) frass is affected by transgenic maize.Ecotoxicology,19(7), 1183-1192. Hernndez-Rodrguez, C. S., Hernndez-Martnez, P., Van Rie, J., Escriche, B., Ferr, J. (2013). Shared midgut binding sites for Cry1A. 105, Cry1Aa, Cry1Ab, Cry1Ac and Cry1Fa proteins from Bacillus thuringiensis in two important corn pests, Ostrinia nubilalis and Spodoptera frugiperda.PloS one,8(7), e68164. Jakka, S. R. K., Knight, V. R., Jurat-Fuentes, J. L. (2014). Fitness costs associated with field-evolved resistance to Bt maize in Spodoptera frugiperda (Lepidoptera: Noctuidae).Journal of Economic Entomology,107(1), 342-351. Roel, A. R., Dourado, D. M., Matias, R., Porto, K. R., Bednaski, A. V., Costa, R. B. D. (2010). The effect of sub-lethal doses of Azadirachta indica (Meliaceae) oil on the midgut of Spodoptera frugiperda (Lepidoptera, Noctuidae).Revista Brasileira de Entomologia,54(3), 505-510. Signoretti, A. G. C., Peaflor, M. F. G. V., Bento, J. M. S. (2012). Fall armyworm, Spodoptera frugiperda (JE Smith)(Lepidoptera: Noctuidae), female moths respond to herbivore-induced corn volatiles.Neotropical entomology,41(1), 22-26. Storer, N. P., Babcock, J. M., Schlenz, M., Meade, T., Thompson, G. D., Bing, J. W., Huckaba, R. M. (2010). Discovery and characterization of field resistance to Bt maize: Spodoptera frugiperda (Lepidoptera: Noctuidae) in Puerto Rico.Journal of economic entomology,103(4), 1031-1038. Storer, N. P., Kubiszak, M. E., King, J. E., Thompson, G. D., Santos, A. C. (2012). Status of resistance to Bt maize in Spodoptera frugiperda: lessons from Puerto Rico.Journal of invertebrate pathology,110(3), 294-300. Tavares, W. S., Costa, M. A., Cruz, I., Silveira, R. D., Serro, J. E., Zanuncio, J. C. (2010). Selective effects of natural and synthetic insecticides on mortality of Spodoptera frugiperda (Lepidoptera: Noctuidae) and its predator Eriopis connexa (Coleoptera: Coccinellidae).Journal of Environmental Science and Health Part B,45(6), 557-561. von Mrey, G. E., Veyrat, N., de Lange, E., Degen, T., Mahuku, G., Valdez, R. L., ... DAlessandro, M. (2012). Minor effects of two elicitors of insect and pathogen resistance on volatile emissions and parasitism of Spodoptera frugiperda in Mexican maize fields.Biological control,60(1), 7-15. von Mrey, G., Veyrat, N., Mahuku, G., Valdez, R. L., Turlings, T. C., DAlessandro, M. (2011). Dispensing synthetic green leaf volatiles in maize fields increases the release of sesquiterpenes by the plants, but has little effect on the attraction of pest and beneficial insects.Phytochemistry,72(14), 1838-1847.