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Will Glyphosate ban worsen tea industry woes?

16 Jul 2015 - {{hitsCtrl.values.hits}}

Reading views expressed by certain eminent personnel in the tea industry, it is quite apparent that the woes of the country’s tea industry is likely to be worsened with the ban of the herbicide Glyphosate which has had no reports of ill effects on residents across tea plantation areas, so far.

There is no alternative to remove the weeds using manual labour which will cost around four to five times more, and it will have to be done more frequently as it is less effective than Glyphosate. Instead, manual removal will erode the soil too.

Chemical weed management will not only minimize soil erosion, but it will also eliminate loss of plant nutrients which are carried away when weeds are removed from the fields.

Weed management
Regulations framed under the Soil Conservation Act prohibits the use of any kind of mammoty, karandi or eeti with a working edge exceeding two inches and overall length exceeding 18 inches for weeding tea plantation areas. I presume that these instructions are valid even to date.

Weeds become a problem when tea bushes are less. Thus, every effort should be made to plant tea bushes without leaving unnecessary gaps and then the question of infilling comes up. If supplying has not been undertaken, it is always advisable to plant vacant patches with cover crops such as mana (Cymbopogen Confertiflours), African love grass (Eragrastis Curoula) or Desmodium Ovalifolium in order to suppress the weed growth. Some weeds which tend to come up above the plucking table such as creepers have to be removed manually.

As chemical weeding does not involve any soil disturbances, it would not stimulate the germinating of seeds of weeds. It is therefore apparent that an effective programme of chemical weeding is more desirable.

However, I am not a scientist. Yet, my personal experience and view is that continuous use of a single herbicide frequently might carry a risk of a buildup of resistant species which may be harmful as well.

Use of Glyphosate
Glyphosate is a water-soluble herbicide and therefore can kill underground parts of many perennial weeds when sprayed on the foliage. It is used to eradicate the infestation of tea fields with couch which are generally in ravines, road sides and boundaries.

Glyphosate can be used in areas which are being reconditioned with grass prior to replanting. A programme of couch control can be initiated from the time a badly infested field is uprooted for replanting.

According to the Tea Research Institute’s instructions, (in 1980’s), it should not be sprayed unnecessarily on a field that is earmarked for uprooting and to remove many couch rhizomes while carrying out deep forking operation.

At this operation, if there is any couch rhizomes left, it should be sprayed later and it should not be used during the time of plucking tea. However, it is important that high yielding fields have to be kept free of couch. Thus, Glyphosate should be sprayed in fields, provided the sprayed patches are left without being plucked for a period of at least three months after spaying.

Although, the World Health Organization has said only 0.5 milligrams of Glyphosate is present in one kilogram of tea, the Tea Research Institute has imposed a two round spray limit annually, to further minimize the risk.

Therefore, I feel, from time-to-time the Tea Research Institute recommends using various other herbicides as well, taking into consideration the herbicide to be used depending on the weed species present at the time of application, and also taking into account the current retail price.

It must also be emphasized that if a particular herbicide is selective only when used within a particular dosage range and, if doses above and below this range are used, the result may be crop damage and inadequate weed control.

(The writer is Former Editor, Ceylon Planter’s Society Bulletin)

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Will Glyphosate ban worsen tea industry woes?

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