Tuesday, November 13, 2012

Tea protection

The tea mosquito bug (Helopeltis theivora) is one of the most serious pests in tea cultivations in India. The loss of crop can be substantial (10-50%). Before the use of chemical pesticides the loss on tea plantations sometimes reached 100% and in commercially grown cashew, losses sometimes reached 30-40%. This translates in a huge loss of revenue in many parts of the country. India is after China the second largest tea producer of the planet. Furthermore, India is the world's largest tea-drinking nation, although the per capita consumption of tea remains a modest 750 grams per person every year. 

Species of the genus Helopeltis are very similar in coloration and morphology, and not all of them are actually equally dangerous to plantations. The only reliable identification based on morphology is the inspection of male and female genital structures but for integrated pest management on a large scale this is not a suitable option. 

That's were DNA Barcoding came in handy as a group of Indian researchers recently barcoded the most common pest species of the genus and furthermore developed some COI primers that amplify species specific regions. If the sequencing of the barcode region is too costly such methods are very good alternatives as a simple PCR run with a subsequent gel check will do it. Species specific markers such as the ones in this study are usually of different length and will migrate differently. This is depicted in the figure on the right for two Helopeltis species.

For someone who has his cup of tea every morning this is very good news.

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