Emerging pests and diseases of litchi (Litchi chinensis Sonn.)

Abstract

Field surveys carried out in litchi growing areas of Bihar during 2009-10 revealed the occurrence of two insect species in severe form which were hither to either unnoticed or of minor importance. They were Apoderous sp., a weeveil and Conopomorpha cramerella, a borer pest on fruits. The weevil was brownish red in colour, about 5-7 mm in length and with a  strong rostrum, causing heavy damage to new flush. Young growing tree of less than five years age were devastated.Similarly a change in disease complex also has been observed. Twig blight symptoms in young orchard were aggravated by leaf feeding insect pest complex. Another such disease is 'litchi sudden death disease'. Young trees of litchi were found to wilt in less than a week time at NRCL experimental farm. A few mycoflora has been consistently isolated associated with fruit drop.  The field collected samples of litchi fruits, affected by fruit cracking, revealed that the exposed aril in the cracks was colonized by Aspergillus flavus. There is apprehension that juices may get contaminated with aflatoxins if inferior quality raw material is used by processors for juice preparation. The changing dynamics of pests and the emerging new pests and diseases may become a hinderance to profitable litchi cultivation and will have socioeconomic impact on litchi growing areas.