Pest attack

Forests in Himachal Pradesh are under attack from a deadly pest

Published: Thursday 30 April 1998

deodar defoliator ( Ectropis deodarae ), a forest pest has affected about one lakh cedar trees in Naganalli and Mihani ranges of Theog forest division of Shimla district, Himachal Pradesh ( hp ). An area of 60 hectares (ha) of cedar forests in Naganalli and 40 ha in Mihani had been attacked by the deodar defoliator this summer, says T D Verma, who is with the department of entomology at Dr Y S Parmar University of Horticulture and Forestry, hp . He fears that the attack may become epidemic, if appropriate action is not taken.

Ectropis deodarae had attacked about 100 ha area in Naldera and Badmain forests of Mashobra and Bhajji ranges. Deodar is a valuable tree growing between 1800 to 2600 metres above sea level in the north-west Himalaya -- comprising an estimated area of 203,263 ha in hp , Jammu & Kashmir ( j&k ) and Uttar Pradesh ( up ). An epidemic in 1900-1901 in Kalala and Theog forests in hp cause large scale destruction.

The damaging stage of pest is Larvae -- only active during April to June -- which responsible for causing large scale damage to trees. The trees particularly at younger stage are more vulnerable. The pest lays eggs on needles of the tree. The eggs usually hatches in the last week of March and the first week of April. The pest affects the trees's natural transpiration and photosynthesis capabilities which results in reduced growth. The trees may die if there are continuous attacks in subsequent years. The pest wrecks havoc until the onset of monsoon when rain brings them down. The affected trees give a completely dry look as if they have been burnt by fire. The pest feeds only on deodar, therefore, no other tree species are affected.

Unlike in the Sal borer forest, hp, nature has played its own course in the deodar trees. A black coloured beetle ( Calosoma beesoni ) and jungle crows ( Corvus machrorhynchus ) are the natural predator of the deodar defoliator. They had helped wipe out whole populations of the pests between 1994 to 1996. But Verma warns in case of epidemics a different approach is required. However, in other case aerial spraying with Malathion or Fenitrothion, but it is not environmentally safe. He says that there is need to go for scientific management as ecology is changing.

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