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NOTES ON TAXONOMY AND BIOLOGY: Ditylenchus africanus differs from D. destructor mainly in stylet and spicule lengths and in RFLPs and rDNA characteristics. Unlike D. destructor, D. africanus does not infect potato. The nematode develops and reproduces in pod tissues causing necrotic discoloration and black or brown stripes. The nematode can also invade the seeds, which appear dark and shrunken. It is able to survive in the hulls and in seeds.
GEOGRAPHICAL DISTRIBUTION: The nematode is common in the Republic of South Africa.
HOSTS: Peanut (Arachis hypogaea) is the principal host. Other agronomic crops and weeds can be infected without showing any symptoms or damage. D. africanus has fungivorous habits and can be reared in fungal cultures (Aspergillus sp., Botrytis sp., etc.)
CROP LOSSES: Nematode infections cause serious qualitative damage and result in 65% of undergraded peanut seeds.
MEANS OF MOVEMENT AND DISPERSAL: Ditylenchus africanus is disseminated with infected peanut hulls and blemished seeds.
RATING: (L) Ditylenchus africanus is a damaging pest in South Africa, however the chances of introduction of this nematode into the United States are limited because imported peanut seeds are used for food processing. Plant breeders should be extremely cautious in importing peanut seeds from South Africa.
REFERENCES:
CAB International. 2001. Ditylenchus africanus
in: Crop protection compendium, global module, 3rd edition. Wallingford,
UK: CAB International.
Dewaele. D., C. Venter, and A. H. McDonald. 1997.
The peanut pod nematode,
Ditylenchus africanus. Nematology Circular
No.218, 6 p. Florida Department of Agriculture and Consumer Services, Division
of Plant Industry, Gainesville, FL, USA.
Wendt, C.D., A. Swart, T.C. Vrain, and J.M. Webster.
1995. Ditylenchus africanus sp. N. from South Africa; a morphological
and molecular characterization. Fundamentals of Applied Nematology 18:241-250.