Used Method Of Control example essay topic

Biological Control (weed): Kahili Ginger Wild ginger is fragrant, leafy, rhizomatous, semi-tropical perennial herb which can grow up to two meters tall. It has a magnificent display of large conspicuous yellow flowers in late summer, followed by scarlet seeds in capsules. In the early 1890's Kahili ginger (Hedychium gardnerianum) was introduced to New Zealand as an ornamental plant. Kahili ginger is a native of India and the lower slopes of the Himalayas in Nepal. It produces massive branching rhizomes which spread and intertwine to create a bed of about a meter deep. Where wild ginger exists in abundance very little else will grow.

The dense root system prevents regeneration of other plants while above ground ginger blocks the light and smothers other species. The major problem areas are Auckland, Wellington and Northland. In these areas (and some other less requiring areas) the ginger is subject to Pest Plant Management Strategies. Currently kahili ginger is invading, and destroying, native reserves, private land, roadsides, recreational areas and even city gardens.

There is growing need and awareness of the danger this weed posses to our natural wilderness. There are two main eradication techniques; manual removal (a very labour some and fairly inefficient method), and the more popular chemical control method. The later is used widely by councils, conservation teams and individuals who are familiar with the ginger's ability to spread and grow from the tiniest rhizome chunk (this can be very disheartening to the amateur conservationist). Manual control can involve pulling small seedlings out by hand.

Removing the flower heads from kahili does not kill the plant but does slow down the spread. If the seeds are not fully formed the flowers can be left on the ground. If they have been formed they head should be disposed of in rubbish bags. For eradication the rhizomes must be removed. They are difficult to pull out, and a cutting tool such as a machete or a spade is often advisable.

The removed debris should not be composted because they will regenerate. Take all ginger parts to the council dump or transfer station, or put them out for domestic rubbish collection. This form of control is effective if the entire ginger community has been removed, otherwise the rhizomes spread. There is a lot of work in this procedure and while it is the most environmentally safe and conservative method it rarely provides the desired result. The second and more widely used method of control: the chemical control method. This involves the use of common herbicides such as Escort, Roundup and Amit role.

These chemical compositions work on the function of the plant rather than the direct removal. The recommended application of the chemicals is between spring and late autumn. It is applied lightly to the leaves and roots. The herbicide is applied to fresh horizontal cuts on the rhizomes, usually with a paintbrush, eye-dropper or a squeeze bottle. By using these convenient instruments less spray is used and less spread occurs. It is considered necessary to sever the rhizomes horizontally to ensure full absorption into the circulatory system, and to apply the chemical immediately so that the sap does not seal the wound.

The plant turns brown and dies after approximately three to four months. During spraying non-target plants are sometimes avoided by using cardboard or plastic sheets. Sometimes spray paints and dyes are used to note previously sprayed plants and areas. The cultural draw-back to this is the dissatisfaction of many environmental groups, who state that the chemicals intrude on the natural state of the environment. Also, socially, the many of the sprays used recommend minimal contact with skin. As these sprays often come in the form of pressurised liquids there is little stopping the drift of hazardous chemical components.

However the chemical method is used there will be some seepage or spread of the elements. For this reason the used of such chemical methods is used sparingly among council groups. Groups such as GreenPeace, Forest and Bird and the Department of Conservation are the most vocal in their opinions on the use of use of chemical pesticides, and their anti-effects. The dangers of chemicals have been seen with the recent claims to money by those effected by agent orange. It is common in history for humans to think lightly of new technology and to disregard the dangers that lurk in the future. It is essential in all sciences to test a treatment prior to the widespread use of it.

If faults are found the substance should not be used. In this case faults have been found. For example, The most environmentally sound control method is manual, but as laziness creeps into the New Zealand culture this method of old has become increasingly redundant. It involves arduous labour and the reward is short-lived if the method is not carried out efficiently. The favoured control method of all those who are unaware of the volatility of the already contaminated environment is the use of chemicals. As we have seen these can be applied to the root or to the leaves.

It has a more effective result and will most likely be the most efficient in eradicating kahili ginger from New Zealand. However, this may come at a price.