Status of Insect Pests of Poplar in India with Special Reference to Clostera spp

As many as 133 insect species so far have been recorded by different workers at various locations infesting different poplar species in India Most of the exotic poplars, especially Populus deltoides have been suffering multiple insect injuries since their introduction in India. Infestation by different insect species to poplar has been reported from time to time by many workers, including Pruthi and Batra (1960); Chatterjee and Thapa (1964); Seth (1969); Lohani (1976); Chatterjee and Chaturvedi (1981); Singh et al. (1983); Singh and Prasad (1985); Singh and Singh (1986); Sohi (1989), etc. Such reports provide specific information of insect incidences. Large scale defoliation of P. deltoides trial plantations (Clones G-3 and G-48, IC-100, 3-4 yrs of age) by Clostera cupreta (Butler) and C. fulgurita (Walker) was reported from time to time from the Central Tarai region of Uttar Pradesh (Seth, 1969; Lohani, 1976; Chaturvedi, 1981; Singh et al., 1983) . By 1980s, the defoliation outbreak spread over an area of 1,100 ha and became alarming. It had to be supressed by aerial spraying of carbaryl (Sevin) insecticide (Singh et al., 1983; Singh, 1998). This defoliator has now spread through out the region of P. deltoides growing. Large scale defoliation by Clostera spp. is known to significantly decrease the growth increment of poplar trees (Gao et al., 1985). Severe and repeated defoliation in young plants results in mortality (Singh and Singh, 1986). Severe attack by Apriona cinerea Chevrolat (poplar stem borer) was reported in 2-3 yrs old P. deltoides plantations, from Paonta Valley in Himachal Pradesh (Verma and Khurana, 1985); Jammu region (Sharma and Bhatia, 1996) and also from other parts of Uttar Pradesh and Haryana (Singh et al., 1987). Attack by this borer into the tree bole renders its timber unsuitable for any commercial use, as the entry of fungus and pathogens in the bored galleries also causes discolouration of its wood. It becomes weak, offering little resistance to wind and gets broken by a modest gust. Repeated attacks result in forking of the bole or mortality of tree (Singh and Prasad, 1985). In view of involvement of large number of insect species in different incidences on poplar trees, there was a need to have complete information of various insect species involved in causing multiple injuries to poplars. Few attempts were made in the past to glean information on poplar insects. Mathur and Singh (1960) were the first to list 42 insect species mostly indigenous to India and adjacent countries that caused damage to poplar and its timber in India. Later, Singh and