Importance of Nematodes in agriculture

IMPORTANCE OF NEMATODES IN AGRICULTURE

In a world-wide survey conducted by sasser, the ten most important genera of plant parasitic nematodes revealed were: Meloidogyne,Pratlylenchus,Heterodera,Ditylenchus,Globodera,Tylenchus,Xiphinema,Radopholus,Rotylenchulus and Helicotylenchus. The estimated overall annual yield loss of the world's major crop due to damage by plant parasitic nematodes is 12.3%.In Indiathe loss is predicted at about 14.6% and could as well go as high as 50-80% in some crops.

             Losses in life sustaining crops grown in deleloping countries are 12.6% compared to 7.0% in developed part of the world. In crops other than  life sustaining ones the losses are 16.5% in developing countries as compared to 10.5% in developed countries.
             In the United states, the nematodes are known to cause 6.0% loss in field crops, 12% loss in fruit and nuts, 11% loss in vegetables and 10% loss in ornamental.In economic terms nematodes cause an estimated loss of about $ 157 billion annually to world agriculture. The loss of Indian agriculture is estimated at about Rs. 210 crore annually.
            The estimated annual losses due to 'earcockle' disease, caused by Anguina tritici on wheat,amounting to $10 million, due to Pratylenchus coffeae on coffee at $ 3 million and due to 'Molaya' disease caused by Heterodera avenae in Rajasthan province alone at $ 8 million. About 3050 ha in Nilgiri hills and 200 ha in Kodaikanal hills are infested with potato cyst nematode. Burrowing nematode, Radopholus similis is responsible for slow wilt disease of pepper in Karnataka and Kerala states. It is also responsible for spreading decline of citrus in Florida, pepper yellows in Indonesia and rhizome rot or black head disease of banana in different parts of the world. Citus nematode, Tylenchulus semipenetrans causes slow decline disease of citrus is also found associated in producing dieback disease of citrus tree in India. The reniform nematode, Rotylenchulus reniformis attack cotton, maize, finger millet, cowpea and blackgram, respectively. The groundnut yield in Rayalaseema particularly in Chitoor district has been significantly reduced due to "Kalahasti malady" forwhich nematode are responsible.