NOTES ON TAXONOMY AND BIOLOGY: Heterodera sacchari is morphological similar to H. elachista, H. oryzae and H. oryzicola. The morphological separation of these cyst nematodes is difficult. Morphological features and biochemical characters of diagnostic value are used for the separation of these species (Nobbs et al., 1992). This cyst forming nematode has sedentary endoparasitic habits. Cysts are persistent tanned sacs derived from the female body and contain the eggs. Cysts persist in soil for many years. Second-stage juveniles (J2) emerge from the cysts, penetrate host roots and establish a specialized feeding site (syncytium) in the stele. They develop into swollen females, which retain the eggs and produce large egg masses. Females rupture root cortex and protrude from root surface. At the end of the reproductive phase, females die and become ovoid brown to dark brown cysts. These cysts are ambifenestrate and are provided by a long vulval slit, rounded semifenestra, few bullae and a robust underbridge showing fingerlike projections (Nobbs et al., 1992)
GEOGRAPHIC DISTRIBUTION: This nematode is common in African and some Asian countries, which include: Benin, Burkina Faso, Congo, India, Ivory Coast, Liberia, Nigeria, Pakistan, Senegal, and Thailand. It has also been reported in Trinidad and Tobago.
HOSTS: Rice (Oryza sativa) and sugarcane (Saccharum officinarum) are the major field crops infected by this nematode. Other plant hosts include bermudagrass (Cynodon dactylon), Brachiaria brizantha, carpet grass (Axonopus compressus), jungle rice (Echinocloa brizantha), sour grass (Paspalum conjugatum), and wild sugarcane (Saccharum spontaneum).
CROP LOSSES: Nematode damage on rice has been documented in Nigeria (Bartola, 1983). This nematode is considered to be a potential serious pest of sugarcane in spite of lack of field experimentation (Luc, 1986).
MEANS OF MOVEMENT AND DISPERSAL: This cyst nematode is dispersed with soil debris and plant material contaminated by the cysts.
RATING: (M) A moderate priority rating was given to this nematode based on its wide distribution, host range, and documented economic crop damage.
Barbatola, J. O. 1983: Pathogenicity of Heterodera sacchari on rice. Nematologia Mediterranea 11:21-25.
Bridge, J., M. Luc., and A. Plowright. 1990. Nematode parasites of rice. Pp. 69-108 in M. Luc, R. A. Sikora, andd J. Bridge eds. Plant parasitic nematodes in tropical and subtropical agriculture. Wallingford, UK: CAB International.
CAB International. 2001. Heterodera sacchari in Crop protection compendium, global module, 3rd editon. Wallingford, UK: CAB International.
Luc, M. 1974. Heterodera sacchari. CIH descriptions of plant parasitic nematodes, Set 4, No. 48. St. Albans, UK: Commonwealth Institute of Helminthology.
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