Pest attacks in Assam (India) plantations hit tea production

[Shiloh]

Source: http://www.bombaynews.net/story/379320

Pest attacks in Assam plantations hit tea production

Bombay News.Net
Monday 7th July, 2008 (IANS)

India's tea production has been hit with rampant pests eating away the crop, adding to the woes of the cash-strapped tea industry in the northeastern state of Assam, officials said Monday.

Planters and industry officials in separate statements said a tea mosquito called helopeltis has attacked nearly 200 of Assam's estimated 800 tea plantations during the past two months.

'There has been a sudden outbreak of blisters on tea plants and soon the attack is spreading like wild fire to scores of gardens in eastern Assam,' Dhiraj Kakati, secretary of the Assam chapter of the Indian Tea Association (ITA), told IANS.

The ITA is the apex administrative body of the Indian tea industry.

According to tea officials, large estates in eastern Assam have borne the brunt of the attack and the production losses are expected to be high.

'The loss in terms of production is estimated at 10 to 15 percent of the total produce and as this is the main production season (May to July), the problem is indeed very serious,' Kakaty said.

'The gardens hit by bugs are all big plantations and produce the bulk of the beverage.'

According to tea growers, the bugs tend to attack plantations during the winter when the young leaves brown.

Assam is crucial to India's $1.5 billion tea industry and accounts for about 55 percent of the total annual production. Along with the mosquito bug, a disease called the bacterial black spot has also hit scores of plantations in eastern Assam.

'When there is an outbreak of helopeltis, we also find the bacterial black spot attack in gardens. This is a serious problem and bound to affect production,' said Mridul Hazarika, director of the Tocklai Tea Experimental Station in eastern Assam's Jorhat town, the heart of India's tea industry. The Tocklai station was set up in 1901 and is currently the world's biggest facility for tea research.

'There are chemicals to control the pests, but then most big gardens, especially those gardens that export teas, avoid using such sprays due to fear of pesticide residual content as western and European countries are very choosy about teas with pesticide residues,' Kakaty said.

India's tea industry was facing a crisis with prices dropping in the weekly auctions since 1998 and exports plummeting as well.

The slump in prices and exports was largely attributed to cheap and inferior quality teas produced by many new tea-growing countries, thereby pushing premium quality Indian teas to facing stiffer competition in the global market.

In the late 1990s, a kilogram of good quality tea from gardens in Assam and south India fetched around Rs.95 to 100, by far the highest average price Indian tea got in the weekly auctions.

Today the average price of tea in the auctions is about Rs.72 a kilogram.

India's traditional tea market in Russia and Britain has been severely hit in recent years with both the countries buying cheap teas from Kenya and Sri Lanka.

 

[Oracle]

Re: Pest attacks in Assam (India) plantations hit tea production

Bugs wreaking havoc in State tea gardens
By Ajit Patowary, Assam Tribune
Monday, July 07, 2008
http://www.assamtribune.com/scripts/details.asp?id=jul0708/at08

GUWAHATI, July 6 ? Plant sap sucking bug Helopeltis, scientifically known as Helopeltis theivora of the Hemiptera family, is now causing extensive damage to tea plants in Upper Assam and West Bengal. According to an estimate made by well-known consultant scientist Prafulla Bordoloi of the P Bordoloi & Associates, who is also a teacher in the Dibrugarh University Centre for Tea and Agro Studies, the loss being incurred by the Upper Assam tea estates due to the attack of the insect may be around ten per cent.

Though some of the office-bearers of the indigenous tea planters? associations differ with Bordoloi in this matter, they feel that it is high time for the Tea Research Association (TRA) of India to initiate serious moves to bring the situation under control.

Bordoloi said that Doom Dooma, Margherita, Naharkotia and Sonari Circles were the worst hit areas. The bug prefers the TV 1 variety of the tea plants more and this is followed by TV 9, TV 26, TeenAli 17, P 126 A and S3A3 varieties. The pest is feared to remain active in the Assam tea gardens till mid-September next. Incessant rains and short rain-free periods during the day hours for spraying pesticides have together made the regular pest control measures fail in the affected gardens.

But compared to the estates of organised sector, the small growers? gardens are less affected. This is because of the small tea growers ability, due to their small-size holdings, to do the repeated rounds of spraying after plucking and also for their reportedly using more toxic pesticides.

Since the big tea companies are concerned over the Maximum Residual Level (MRL) of the chemical pesticides, it has become a hindrance in their gardens to control the pest effectively, said Bordoloi. Control of the pest is very difficult if spraying is not done at regular interval. Pesticide application does not always kill the embedded eggs in plant tissues totally and as a result nymphs are hatched within 4-6 days in June-July, 5-6 days in August-September, 16-21 days in November-January and 7-8 days in March-April. Soon after hatching, the nymph starts sucking on young tender leaves and buds.

A single female lays about 220 eggs in 36 days and 4 to 10 eggs per day. The male of the pest lives for 26 to 55 days and the female for 32 to 36 days.
The nymph and adult Helopeltis suck the sap of the young leaves, buds and tender stems and while doing so injects toxic saliva causing the breakdown of the tissues surrounding the punctured portion of the plant. The badly affected leaves become deformed and even curl up. In a severe attack, bushes virtually cease to form shoots and affected area may not flush for weeks together.

A single full-grown nymph or adult can produce about 200 spots in a day and thus causes severe damage to the bud, foliage etc within a few days. To stop the phenomenal growth of the bug?s population, it is necessary to repeat the pesticide application before its young ones become adult and lay eggs, said Bordoloi. He also informed that strong pesticides like ?Alphamethrin? also kill natural enemies of the bug and thus conversely contribute to its growth.

The pest is not new in India nor it is unknown in other parts of the world. Helopeltis damage is common in Terai, Dooars and Darjeeling tea gardens of the country, said Bordoloi. Tocklai has been regularly taking up research projects on control of Helopeltis since 1903. But a permanent solution to the problem could not be found so far, even though those following Tocklai guidelines are likely to suffer less, said Bordoloi.

Chairman of the Assam Tea Planters? Association (ATPA) Abhijit Sarmah has said that there is about ten per cent crop loss in Upper Assam gardens due to Helopeltis attack this time. The recently hiked prices of the needed pesticides have created problems for the tea estates, he said. The number of ATPA member gardens is 180.

Additional Chairman of the Bharatiya Cha Parishad Robin Borthakur said that the damage caused by the pest particularly this year had been tremendous in Upper Assam leading to an average crop loss of about 25 per cent during June alone. He said that in view of the continuous rainfall the prospect appeared gloomy for July as well.

Unless suitable measures are taken immediately, the pest, together with black rust, is going to do irreparable damage to the future prospect of tea in Assam. The TRA should work overtime to find ways for effective control of this unprecedented attack of the pest, he said.

President of the North East Tea Association (NETA) Manoj Jalan maintains that although stray incidents of Helopeltis attack have been reported by the member gardens, the problem has not attained epidemic proportion in Golaghat and Karbi Anglong district. However, overall crop continues to be lower by 10 per cent to 15 per cent, compared to last year, he said. The NETA has around 60 member gardens.

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The report above mentions frequent application of toxic pesticides in smaller tea plantations to control insect damage and fungal disease, and the increased global distribution of said specialty tea garden products in response to enthusiastic tea consumption abroad, raises the issue of consumer pesticide exposure.

Pesticide presence in dried tea product might be a function of type pesticide used and it's oleophilicity, leave processing, the effect of open air and oven drying and fermentation, and storage duration.

The Brits and Asians have traditionally 'washed' tea leaves before brewing tea (to remove dust and for frequent tea drinkers, to reduce caffeine intake). Americans are less likely to prepare their teas in traditional teapots, preferring cup/difuser and tea presses to prepare small quantities and to save time. The Asian brewing method of short steeping times may reduce exposure, although repeated extraction (up to 7 times for oolong and pur'eh types) may increase exposure. Tea leave washing may or may not reduce pesticide exposure from dried tea leave brewing.

Dissipation behavior of propargite--an acaricide residues in soil, apple (Malus pumila) and tea (Camellia sinensis). Chemosphere. 2005 Feb ;58 (6):837-43 15621197

Propargite, recently introduced in India, is an effective acaricide on a large number of crops most of which are consumed by human beings directly or after processing. Therefore, it has become important to check the dissipation behavior of propargite in edible raw commodities, processed products and in the environment. In the present study, dissipation of residue of this acaricide in soil, apple fruit and tea (green tea leaves, manufactured tea, infusion and spent leaves) was studied. Analysis was carried out using high performance-liquid chromatography with UV detection system. The dissipation rate was found to vary with the nature of studied crop/sample. In soil, half-life ranged from 43 to 45 days, while in plant matrices (tea and apple) it ranged 1.66-2.61 days. The percent transfer of propargite residue from manufactured tea to infusion was 23.60-40.00; however, 35.71-53.20% of the residues remained stuck to the spent leaves.

Leaching of pesticides in tea brew. S Jaggi, C Sood, V Kumar, S D Ravindranath, A Shanker. J Agric Food Chem. 2001 49 (11):5479-83 11714347.

A cup of tea that cheers can also be an important route of human exposure to pesticide residues. It is important to evaluate the percent transfer of pesticide residue from dried (made) tea to tea infusion, as tea is subjected to an infusion process prior to human consumption. To investigate the pesticide translocation, 13 pesticides commonly used on tea were studied by subjection of fortified teas to infusion. Analytes of interest were quantified by gas-liquid chromatography with nitrogen-phosphorus and electron capture detectors. Interestingly, water solubility of pesticides did not necessarily indicate a shift of residues toward their preferential accumulation in infusion. The pesticides with larger partition coefficient (K(ow)) values remained nonextractable in infusing water. Further, boiling for longer periods (extended brewing time) resulted in higher transfer of pesticides to tea brew.

A modified extraction and clean-up procedure for the detection and determination of parathion-methyl and chlorpyrifos residues in tea. A Shanker, C Sood, V Kumar, S D Ravindranath Pest Manag Sci. 2001 57 (5):458-62 11374164.

Recent advances in methodology and instrumentation have made possible the detection and determination of pesticides at microgram kg-1 (ppb) levels. The sensitivity of a method of analysis depends greatly on the efficient extraction of the pesticide and the subsequent clean-up of the extract. The extract from green tea leaves is a mixture of aroma components, polyphenols and caffeine. The preparation of made tea from green tea leaves adds to this complexity by concentrating these coextractives. Conventional clean-up techniques provide poor recoveries for parathion-methyl and chlorpyrifos from both green tea leaves and made tea. This arises from interference by caffeine during gas chromatography, as it has a similar retention time to the two pesticides and peaks overlap. A modification to the protocol based on a solvent partitioning process using dichloromethane and subsequent washing of the extracts with warm water removed the caffeine, and pigments were removed by column chromatography. Recoveries ranging from 80 to 90% were then obtained for both pesticides.