Bacillusthuringiensis and Gypsy Moth - Essay Example

Bacillusthuringiensis (Btk) and Gypsy Moth Bacillusthuringiensis (Btk) and Gypsy Moth Lymantria dispar, the gypsy moth, is one of the most dangerous insects in Northeastern United States’ forests and sheds. It is a polyphagous insect. The pest’s larvae have been for ages responsible for defoliating acres of forested lands as well as shrubs and trees in residential areas. Additionally, the insect has causes negative significant negative economic impacts. According to Sparks, Michaels and Daniels (2013), defoliation caused by the insect is a cause of a major concern especially in the Cork Oak Forest. There are fears that the feeding endeavors of the gypsy mouth may lead to complete defoliation of Quercus suber L. trees. Sparks, Michaels and Daniels (2013) reiterate that the larvae of Lymantria dispar have often caused significant defoliation in the past. Lymantria dispar’s life cycle usually start over the season of winter when the insects lay large masses of eggs. Ruiu and Roberto (2013) reiterate that these eggs hatch in generous numbers over the seasons of spring. Lymantria dispar represents a noteworthy risk to forests in various parts of the world. Preservation of the Cork Oak Forest would require implementation of proper management programs. In the past, forest conservation bodies have often considered several management approaches to control the adverse effects of Lepidopteran defoliators. However, some biological and practical limitations have of alternative pest control methods to contain the infestation of the defoliators over large tracks of lands have been observed. Currently, environmental conservation bodies have concentrated on the use of entomopathogenic microorganisms such as Bacillusthuringiensis (Btk) given the reason that these organisms’ impacts can be felt over large areas. Bacillusthuringiensis (Btk) products have become increasingly crucial as integrated means of pest management and are incessantly being employed in the control of pests in agro systems and forests around the globe. Bacillusthuringiensis (Btk) formulae that are used in the control of Lepidoptera consist of a concoction that includes parasporal bodies such as crystals and bacterial spores. The parasporal bodies contain insecticidal toxins such as the cry proteins. In the view of Sparks, Michaels and Daniels (2013), the gypsy moths consume the proteins which become activated after they are injected into their bodies. The proteins then become bound to specific plasma membrane receptors on the midgut section of the insect pests; epithelium. They sip into the cell membrane and determine the formation of amphillic pores. Sparks, Michaels and Daniels (2013) summarize that an abnormal influx of ions and water into the epithelial cells results and this leads to cell lysis. As a result of the actions of the proteins, paralysis occurs to the larvae and thus causes death to bacterial septicae –mia (Sparks, Michaels and Daniels 2013). Whenever a larva is treated with Bacillusthuringiensis (Btk), it develops slower than uninfected insect pests and leads to hatching of gypsy moths that are smaller in size than would otherwise be. The smaller sizes of the hatched moths render them vulnerable to attacks parasitoids. The result is a higher parasitism on the gypsy moths and an ultimate control in number of the moths. Additionally, research has shown that larvae that are treated using the Bacillusthuringiensis (Btk) approach are more likely to perish along with their parasitoids. The said research was conducted within a period of two years using different formulations of Bacillusthuringiensis (Btk) in the spring of 2012/2013. It was carried out in the endangered Cork Oak Forest against the disastrous gypsy moths within North Western Sardinia (Sparks, Michaels and Daniels 2013). Data collected from the study showed how the Bt treatment affected the larvae of gypsy moth treated with it. The mean number of larvae on 8 branches per tree ranged from 0.50 to 2.25, with no significant differences amid treatments (F = 0.75, df = 6, P = 0.6129). All tested products proved to be effective against L. dispar larvae under open field circumstances (Sparks, Michaels and Daniels 2013). The tested managements significantly reduced the number of both lepidopteron species in contrast to the untreated management. And for L. dispar one (F= 5.74, df = 6, P = 0.0012) and two weeks (F = 8.13, df = 6, P = 0.0001) after treatment application in 2013 (Sparks, Michaels and Daniels 2013). From this, it was observed that the proportion of defoliation levels after treatment applications were considerably higher in untreated control plots than in treated plots for both 2012 and 2013. Therefore, showing that the treatment had a constructive impact in reducing the numeral evidence of larvae treated In addition, another survey carried out on the insect pest Lymantria dispar (gypsy moth) was characterized in the larval mid-gut in rejoinder to contamination by Bacillus thuringiensis kurstaki (Btk). The researchers used RNA approach to define a set of 49,613 assembled transcript sequences, of which 838, 1,248 and 3,305 were respectively partitioned into high-, mid- and low-quality tiers based on homology information. Digital RNA expression profiles were suggested. This survey was carried out to exclusively investigate the reaction of the gypsy moth to a bacterial contagion. Results showed that organically based management machinery could be used against the gypsy moth to control it. In as much as the there are notable levels of success on the use of Bt approaches in the control of gypsy moths, there are a number of limitations of the scheme. One of the limitations of this method is that it is dose dependent. The method achieves a high efficacy with increased dosage of Bt (Ruiu and Roberto 2013). The dosage has to be high for the treatment to realize good results. Higher dosage calls for the need of more economic resources in the control of gypsy moths (Erb & Bourchier 2001). As such, the method is expensive if it has to effectively control the gypsy moth. Moreover, despite prevalent usage of Bt for gypsy moth restraint, the scope of target insect transience that can be achieved is limited by ecological and technological constraints. For example, in airborne spray programs, larvae only devour a sub lethal rather than a fatal dose. The disadvantage is that sub fatal effects of Bt on the bug are not yet well comprehended (Ruiu and Roberto 2013). This is due to the fact that a majority of researches so far conducted in the field only focus on the larval mortality. Despite the inherent limitations, Bt products provide one of the most effective methods of controlling gypsy moth. There is need to encourage the use of the method in continued clearance of forests against the voracious gypsy moth. Bt-based products should be used as a method of managing gypsy moth. Compared to other available methods of related management, it has the ability to contain the forest defoliators over large tracks of land. In addition, the method is an effective means of reducing the adverse negative effects that are caused by the gypsy moth. In conclusion, these results show that all formulations of Btk strain EG 2348 seem to be successful in protecting Cork Oak trees from L. dispar. Both schemes of Btk strain EG 2348 have been observed to be successful in controlling the invasion of the gypsy moth; thus showing a probability of forest protection (Ruiu and Roberto 2013). The researches reveal that the defoliation levels were considerably higher in untreated control trees than in treated ones. These treatment outcomes show that the Bt products tested have the effect of lessening the number of larva treated with it. It, therefore, proves to be presently an effective method of controlling gypsy moths over a large area as contrasted to other pest control products Bibliography Erb, S. L., R. S. Bourchier, K. van Frankenhuyzen, and S. M. Smith. Environmental Entomology. December 2001. http://www.bioone.org/doi/full/10.1603/0046-225X-30.6.1174. Ruiu, Luca, Roberto Mannu, Giovanni Falchi, Andrea Braggio, and Pietro Luciano. EVALUATION OF DIFFERENT BACILLUS THURINGIENSIS SV KURSTAKI FORMULATIONS AGAINST LYMANTRIA DISPAR AND MALACOSOMA NEUSTRIA LARVAE INFESTING QUERCUS SUBER TREES. 2013. Sparks, Michael E., Michael B. Blackburn, Daniel Kuhar, and Dawn E. Gundersen-Rindal. "Transcriptome of the Lymantria dispar (Gypsy Moth) Larval Midgut in Response to Infection by Bacillus thuringiensis." www.plosone.org. 2013 May. Read More