A large number of Yongchak trees (Tree Bean) in Willong Khunou village of Senapati district in Manipur are reportedly infested by an army of invasive caterpillars identified as Pericyma, a type of defoliator, causing panic among the villagers.
It is reported that almost all the trees of the village which borders Nagaland are infested by the caterpillars.
A villager said they spotted the caterpillars only recently and the pests have consumed almost all the green portions of Yongchak trees within a short span. Within two-three days almost all the trees have been eaten and the pests even entered the nearest houses.
“Annually, villagers earn around Rs 2 lakh approximately from producing Yonchak which is a popular delicacy in the state. Now, the villagers are apprehensive of losing their livelihood,” the villager by the name Bosco said.
Yongchak is the main source of income of the village. Almost all the households of Willong Khunou and Rajaimei village of Senapati district depend on Yongchak as their source of income. Every house has 30-40 Yongchak trees. The semi-loppers have not spared even the newly planted trees.
The pests have even started entering the houses. It is the first time such insects have eaten all the trees, the villagers said.
“The village started Yongchak cultivation for the last five-six years and has been giving importance to the plant as a source of livelihood. Earlier, the Yongchak trees were not given much importance even if they grew vastly,” he added.
A joint team of Krishi Vigyan Kendra (KVK) Senapati and e-loumee, a platform for farming experts, visited the hill village located about 150 km northwest of Imphal on Sunday and confirmed the development. They visited the village to oversee the situation, said farm manager of KVK Senapati Homen Kangjam. “We’ve also collected pest samples for further study,” he said.
These loopers are seen in large numbers in every Yongchak tree and village areas, including house walls, he said.
E-loumee managing director, Senjam Jinus said they have identified the pests which were causing huge destruction of Yongchak trees at Willong village.
As reported, Pionciana looper larvae can cause extensive defoliation, reduce flowering and become a nuisance to residents as caterpillars drop from trees. It had been reported to feed on Delonix regia, Desmanthus virgatus, Peltophorum.
However, in Korba, the larvae of Pcruegeri were observed feeding on young leaves of Delonix regia. The first outbreak of P Cruegeri was reportedly noted during August 2020 from the Korba and Katghora regions of Chhattisgarh.
Plant protection scientist Krishnakumari Devi told the Imphal Free Press that the pests may come from the same host family.
“It may also be due to changing climate, temperature or weather. Insects can reach from place to place. So, while reaching the village the insects might have found Yongchak as their food and consume everything i.e. from leaves to the flowers of trees. These can be further confirmed by studying them in a laboratory,” she added.
Meanwhile, officials of the Horticulture and Soil Conservation department have started remedial measures by spraying the trees with organic medicines.
District horticulture officer Kh Upen, told the Imphal Free Press that the samples have been sent to the Indian Council of Agricultural Research for investigation.
Indian Council of Agriculture Research, joint director I Meghachandra sent a confirmation of the semi lopper to the director of Horticulture and Soil Conservation, stating that the sudden outbreak of the unidentified insect noticed in some places of Senapati district is Pericyma species, a type of defoliator semi-looper.
As per his confirmation, the entomologists of the centre have studied them and they are polyphagous (able to feed on various kinds of food). The younger stage larva is light green with grey and white longitudinal lines on the body and black and yellow lines on the lateral side with distinct yellow head. The mature larva (body length reaches 48 mm) is characterised with white longitudinal lines on the dorsal and black and yellow lines on the lateral side with distinct orange or red heads, as per the confirmation. The caterpillar is characterised with three pairs of thoraic legs and three pairs of prolegs. The identification of species is in progress.
Some chemical insecticides have been suggested to be applied for immediate relief from ICAR. They are Cypermethrin 10 per-cent EC @ 1ml/litre water; Fipronil 5 per cent SC @ 3ml/litre water; Chloropyriphos 20 per cent EC @ 2ml/litre water; Spinosad 45 per cent SC @ 0.15 ml/litre water.
The recommendation dose can be mixed properly with a sticker of 2-3 ml litres of water. For spraying on all trees particularly in the hill slopes, drone sprayers are recommended for larger coverage. It is mentioned that the same insect/pest is also reported from Ukhrul and Kamjong district as well.