State embarks on proj to save orange orchards from pests
“Catch a Trunk Borer and earn money” claims an advertisement by ‘Mission Suntala’ an initiative to save the world famous Darjeeling Mandarin’s by the Directorate of Cinchona and Other Medicinal Plants, Government of West Bengal. Trunk Borers are pests (insects) that destroy the orange plants. It is a double benefit for the Mandarin farmers of the Kalimpong and Darjeeling Hills.
Any person catching these insects, dead or alive and depositing them at the Directorate will be paid Rs 50 per female insect and Rs 30 per male, states the advertisement.
The Mandarin Orange (Citrus reticulata blanco) is a major cash crop of the Darjeeling Hills. It is grown in approximately 930 hectares in the Darjeeling Hills. Orange production in Darjeeling and Kalimpong hills has continuously declined for the past many years.
The Bengal government committed to revive this treasure of the hills has embarked on an ambitious project on a
mission mode called the ‘Mission Suntala’ with the aim of rejuvenating the existing orchards and addressing various problems being faced by the orange growers. “Suntala” is the Nepali word for oranges. Pests are one of the major problems affecting the plants.
The Trunk Borer Grub (Anoplophora versteegi) tunnels into the trunk and feeds on the internal content of the trunk of orange plants resulting in death of the plant. Adults feed on the leaf tissue along the midrib, keeping margins intact. A female lays 35-85 eggs singly in cracks on the bark around 2 feet height from the ground. Grubs feed on sapwood making horizontal galleries before entering into the centre of the trunk, larval period is 267290 days. Pupation takes place inside the gallery pupal period 33-43 days. Freshly emerged beetles take 3-5 days for hardening of body parts and thereafter start feeding on citrus leaves and bark. Control measures for this pest are difficult because of the cryptic habit of the grubs and the active migration of the adult beetles.
“This is the time when female trunk borers lay eggs. Chemical sprays are not good for the plants hence it is best to catch them manually. The monetary incentive is already yielding results. As the insects cannot fly much it is easy to catch them manually. On Friday a farmer in Bijanbari caught 10.
We have also devised a way by which anyone catching the insects can show us the insects through video call and the amount will be deposited to their bank accounts. They will not have to spend money and travel to the directorate offices in Mungpoo from far away places,” stated Samuel Rai, Director, Cinchona.