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A few minutes' walk into the forest near Sontirath village is enough to make one notice the quiet provided by the dense sal (Shorea robusta) tree growth. There is a sudden sense of self-awareness as one starts to notice the faintest of forest sounds. “It will not be this peaceful for long. Come monsoon and the forest will be full of sal borers flying around,” says Sukaal. “The pest is in the larva stage right now. The adult insect will emerge from the tree in June-July, with the onset of rains,” he adds.
Sukaal is among the 35-odd labourers deployed by the forest department in Madhya Pradesh’s Dindori district to identify sal trees that have become infested by the sal heartwood borer (Hoplocerambyx spinicornis) insect in the forest near Sontirath village. His job entails scalping the bark of the infected trees to leave a square mark on the trunk. “I do not like this work. But we need to identify the infected trees so that they can be felled to control the spread of sal borer,” Sukaal says.
The dark brown insect, about the size of a human finger, is considered the biggest threat to forestry in India, especially to sal trees, where it lives and breeds, though it also infests other species including shisham (Dalbergia sissoo), deodar (Cedrus deodara), rubber and fruit trees like apple. While it usually attacks weak, damaged trees, sal borer can also infest healthy ones. “The insect is drawn to sal’s sap and resin and can smell a wounded tree secreting sap from a kilometre. A freshly cut sal attracts insects within minutes and they can hollow it out in days,” says Sohanlal Baiga, another labourer marking trees in the forest. “Trees with sal borer infestation become dry and yellow, and can be identified by the wood dust that surrounds them,” he says.
Native to India, sal is the second most important tree after teak, both ecologically and economically. It is prized for its usability in making furniture, as well as in the construction sector, the leaf-plate industry and for its seed oil. But every year, borer infestations destroy sal trees by the thousands across the country. If fallen trees are not removed from forests and favourable climate conditions for its growth sustain for a couple of years, the sal borer population multiplies to such an extent that an outbreak occurs. Experts say a forest has a sal borer outbreak when the number of infested sal trees becomes more than 1 per cent of the total sal trees.
The last sal borer outbreak in India was in 1996-2001, when Madhya Pradesh and Chhattisgarh lost 3.5 million trees, states a paper presented at the XII World Forestry Congress in Canada in 2003. The two states account for 2.88 million hectare (ha) of India’s 10.05 million ha sal forest cover (over 25 per cent), as per a 2006 document of Tropical Forest Research Institute (TFRI), Jabalpur (see ‘Distribution of sal’). This year, there are indications that same two states could face a much severe outbreak.
Consider this. On November 30 last year, the Madhya Pradesh forest department started identifying and marking trees in the 119.25 ha forest near Sontirath village. “By December 3, 2025, when the work had been completed in just 3 ha, a total of 3,113 sal borer-affected trees had been identified,” says an official on condition of anonymity. Marking the entire 119.25 ha forest could take up to a month, and the number of affected trees could reach 0.1 million, the official tells Down To Earth (DTE).
Dindori’s Divisional Forest Officer (DFO), Puneet Sonkar, acknowledges that the number of sal borer-affected trees has been steadily increasing for the past two to three years. “Local staff and village residents are reporting its impact in the East Karanjia Range, West Karanjia Range and South Samnapur. Sal forests are more prevalent in East Karanjia Range, West Karanjia Range, South Samnapur, North Samnapur, Bajag, Amarpur, Dindori and Shahpur ranges. Therefore, counting is being done in all these areas of Dindori district,” he says. “In 2024, about 5,000 sal borer-affected trees were identified. Once the counting is done and data is available for this year, we will be able to assess the percentage increase. Until then, the situation cannot be called serious or alarming,” DFO Sonkar adds.
Uday Homkar, Senior Research Officer (SRO) and entomologist at the State Forest Research Institute (SFRI), Jabalpur, also says that though the infestation is slightly higher this time…
This article is part of the cover story Waiting to strike published in the February 1-15, 2026 print edition of Down To Earth