Asian Gypsy Moth - Report Example

Asian Gypsy Moth The Asian gypsy moth is believed to be one of the most destructive pests. Due to their destructive potentials in forests, several countries have put in place measures to counteract their incursions. Although there have not been serious incidences of this pest species invading New Zealand, the government through the ministry of agriculture and forestry (MAF) has been on high alert in order to avoid importation of the pest in the country. This paper will focus on characteristics of this pest and assess ways through which New Zealand has dealt with it. Introduction: the origin, Characteristics/Adaptations, Life History, Reproductive Potential, Ecological Function, Ecological Niche of Asian Gypsy Moth The Asian Gypsy Moth (AGM) is argued to be a highly destructive forest pest (Ross, 2005). It feeds on both deciduous and coniferous trees. The female moth is capable of traveling up to 21 nautical miles. Their feeding behavior is known for its devastating effects – it leaves trees weakened and susceptible to disease and other pests (Glare, Hajek, & OCallaghan, 2009). AGM live between the latitudes of 240 and 600 North. Areas under risk of invasion include Japan, South Korea and North Korea, the Far East, and north China. The AGM’s flight season is when the females lay eggs, and is usually between June and September in southern and central Japan, from June to September in Korea and Northern China, and in August and September in the Russian Far East, including North Japan. It is believed that female AGMs are active flyers and are attracted to bright lights, meaning that their eggs may be found in the vicinity of exterior lights (Ross, 2005). On the other hand, male AGMs are grayish brown and smaller than the female AGMs. Female AGMs are whitish in color with noticeable black marks on the wings. AGM eggs are velvety in texture. Their colors range from light tan to dark brown. Ross (2005) also noted that these eggs are harder and more resistant to changes of temperature and moisture. It is believed that they are deposited in sheltered areas: for instance, in crevices, behind walls and doors, and underneath framings. The larvae usually hatch in early spring, which is argued to be the high risk period in countries they have invaded. The major period for egg hatching is in the morning. The larvae climb rapidly to a high point and widely disperse on silken strands by the wind until they find a suitable host trees to feed on (Ross, 2005). Implications of an Invasion of the AGM Several ships in New Zealand ports have been found to have viable AGM egg masses. These findings have raised awareness of the danger of this particular pest reaching the shores of New Zealand (Ministry of Agriculture and Forestry, 2008). However, a risk assessment by the ministry of forest concluded it is unavoidable that AGM will reach New Zealand and that their arrival would be devastating. The only elucidated examination concerning the adaptation of AGMs in New Zealand has been pathways by which the AGMs could find their way in the country. Important concepts like the requirements for the establishment of AGMs in the country have not been fully examined. However, there are suspected suitable host tree species that favor the pest in New Zealand, but a clear understanding of the threat to New Zealand has not been identified (Ross, 2005). This is arguably true because no host testing has been carried out for AGMs through the use of New Zealand trees. The only partial understanding of the threat of the pest heavily relies on feeding trials carried out in the US and which indicated that AGMs can have their life cycle completed on eucalypts and some pines. However, this cannot be argued to be a measure of threat, because clear biological probabilities could also play a part in assessing the survival of the pest (Glare, Hajek & OCallaghan, 2009). On the other hand, AGMs were introduced in the US from France in 1868 near Boston and later slowly spread over a large portion of eastern North America. However, the slow spread of the species can be attributed to a lack of mobility since females in these regions are flightless (Hajek, 2004). It is believed that since AGM is difficult to eradicate, the US department of agriculture has adopted an approach to fight the pest. The impacts of AGM in North America are argued to be manifold. Defoliated trees grow slowly. Oaks are totally defoliated, and it may take some time before they produce new leaves. These processes of defoliation and refoliation cause a net reduction in the population of trees (Ross, 2005). It is also argued that defoliation affects aesthetic quality and recreational values. In fact, it has been noted that home owners are willing to pay any amount in order to protect their shade trees from AGM defoliation. Pathway AGM could enter New Zealand from any East Asia country. Available evidence suggests that the most likely pathway for AGM arrival in New Zealand could be through used vehicles, particularly from Japan (Ministry of Agriculture and Forestry, 2008). Although current measures to reduce the likelihood of AGM arrival in New Zealand are in place, it is believed that these measures do not reduce it to negligible levels. A major concern is on the sea container pathway. It is argued that there is little information on the association of AGM with sea containers. However, according to Hajek, (2004), available information suggests that egg masses are highly likely to occur on their lower surfaces, thus making it hard to detect. All in all, the likelihood of AGM establishment is lower than that of other species, since it characteristically has one generation in a year and its life cycle is highly linked to seasonal changes. In this regard, AGM has to defeat the seasonal invasion from the northern to the southern hemisphere (Ross, 2005). It is believed that the seasonal inversion has the likelihood of reducing the establishment, although it cannot prevent the establishment from occurring. Incursion Response On March 2003, ten years after a national trapping program was initiated, it was learned that the first male gypsy moth was netted in the Hamilton. It was later discovered that it was an Asian strain from Japan. It was believed that the incursion was a result of an egg imported to New Zealand through used vehicles. As a result of this, the government through the MAF recommended the pursuit of AGM eradication (Glare, Hajek, & OCallaghan, 2009). A technical advisory group convened to evaluate the initial findings of the intensive surveillance in order to advise on the best response strategies. One of the recommendations by the ministry was to use the aerial spraying of bio-pesticides followed by mass trapping in order to be sure of successful eradication (Ross, 2005). After the initial assessment was complete, the ministry opted either to do nothing and continue with monitoring efforts or to implement eradication. However, with the assistance of both New Zealand and international scientists, it was concluded that one gypsy moth poses a risk that it will establish a population; therefore, there was a need to have vigorous measures to prevent the pest from dispersing to other areas. In this regard, aerial spraying was considered ideal. Thereafter, a high density trapping grid would be erected in a 1 km radius around the find. This was argued to help detection of any male moths that mated with a female (Hajek, 2004). Critique of the Incursion Response It is apparent that AGM was detected before spreading to other areas. However, it is true to argue that the absence of another moth does not automatically mean that the trapped male was the only one. It is likely that some larvae could have build up to maturity and left some other areas adjacent to Hamilton (Ministry of Agriculture and Forestry, 2008). It is also argued that in low populated areas, many females build up from one egg mass, meaning that males are few. This has an implication that other female moths had been deposited elsewhere. In light with this, a more vigorous search ought to have been done in order to find whether there could have been likelihood that additional moths had been disposed elsewhere. Setting up traps only in suspected areas was not enough. All in all large numbers of traps are needed in order to intensify eradication attempts. It can be argued that netting one moth is a sign that this was done in a timely manner. If there were several of them netted the first incidence, this would have been an indication that it was delayed. At the same note, according to the modes of transmission of the moths, it can be argued that having the moth netted along the transit path, this was the only way to have trapped them. Nevertheless, since these moths can fly for quite some miles, there is a possibility that they could have entered the country not necessarily through transit roots. Therefore, given that the moths could have entered the country either through transit roots during their larvae stage or via flying from the neighboring countries, then it is true to argue that there was not easy to have detected them. Strategies used to trap moths can be used to be appropriate (Ross, 2005) since this was the first case to be reported in the country. However, evidence of existence of AGM in other countries was enough to have provoked New Zealand to set traps in case of any moth trying to enter the country. Conclusion AGM is believed to be a highly destructive forest pest. They live between the latitudes of 240 and 600 North. Their eggs are harder and resistant to changes of temperature and moisture. The larvae usually hatch in early spring. The larvae climb rapidly to a high point and widely disperse on silken strands by the wind until they find a suitable host trees to feed on. The first male gypsy moth was netted in the Hamilton. However, several ships in New Zealand ports have been found to have viable AGM egg masses. The only elucidated examination concerning AGM’s adaptations in New Zealand has been pathways. The MAF recommended the pursuit of AGM eradication. One of the recommendations by the ministry was to use the aerial spraying of bio-pesticides and then to implement mass trapping in order to be sure of successful eradication. References Glare, T., Hajek, A., & OCallaghan, M. (2009). Use of microbes for control and eradication of invasive arthropods. Dordrecht; London: Springer. Hajek, A. (2004). Natural enemies: An introduction to biological control. Cambridge; New York: Cambridge University Press. Ministry of Agriculture and Forestry. (2008). Pest risk analysis for six moth species: Lessons for the bio security system on managing hitchhiker organisms. Retrieved from http://www.biosecurity.govt.nz/files/biosec/consult/risk-analysis-moths.pdf. Ross, M. (2005). Response to a gypsy moth incursion within New Zealand. Retrieved from: http://www.biosecurity.govt.nz/files/pests/gypsy-moth/residents/response-gm-incursion.pdf. Read More