TABLE CONTENTS

The Presence of Plant Parasitic Nematodes in Peanut Pods
Tiedt, L.R. (1), A. Swart & M. Marais (2)
(1) Laboratory for Electron Microscopy, North-West University, Potchefstroom Campus, Potchefstroom 2520,
South Africa; (2) National Collection of Nematodes, Biosystematics Division, ARC-Plant Protection Research
Institute, Queenswood 0121, South Africa.
In South Africa peanut pod shells are commonly used as ground cover in horticulture. The
presence of Ditylenchus africanus in peanut pod shells and its detrimental effect on peanut
production in South Africa are well documented, prompting the authors to search for other
plant parasitic nematode species which might also lurk in peanut pod shells. On examination
of shells from farms in the Vaalharts Irrigation Scheme in the Northern Cape Province, we
found D. africanus, Meloidogyne sp,., Aphelenchoides arachidis and A. blastophthorus.
According to the South African Plant-Parasitic Nematode Survey (SAPPNS) database and
literature, Pratylenchus brachyurus, Tylenchorhynchus brevilineatus and Criconemoides
ornatus are also found on peanut shells. All these nematodes are risk species in the
cultivation of peanuts but what is disconcerting for the home gardener, who uses peanut
shells as mulch, is the large list of other host plants that they also attack. Most ornamental
plants some turf grasses and vegetables such as tomato, beans, peppers, carrots, cucumbers,
eggplant, are attacked by the root knot nematode, Meloidogyne. Pratylenchus brachyurus
attacks among others apple, beans, citrus, grape, peach, pear, strawberry, rose, most
vegetables and turf. Criconemoides ornatus affects potato, sweet potato and also ornamental
plants. The effect of D. africanus and A. arachidis on plants other that peanut and cereals has
never been established, but other legumes might be potential hosts for these nematodes.
When adding compost or ground cover, containing peanut shells care must therefore be taken
as there are currently no nematicides or soil fumigants available to home gardeners.
Burrowing Nematode (Radolpholus similis) on Ginger in Fiji
Turaganivalu, U. (1), G. Stirling (2) & M. Smith (3)
(1) Fiji Ministry of Agriculture and Primary Industries, Box 77, Nausori, Fiji; (2) Biological Crop Protection,
3601 Moggill Road, Moggill, Qld, 4070, Australia; (3) Department of Primary Industries and Fisheries, PO Box
5083, Nambour, Qld, 4560, Australia
Radopholus similis multiplies readily on ginger in Fiji and in situations where the nematode
reaches high population densities, cavities form in rhizomes and affected tissues are
discoloured. Recent surveys have shown that economic losses from R. similis are not as
common as they were 20 years ago, largely because most Fijian ginger is now harvested
about 5 months after planting rather than being grown to maturity. Another reason for a
reduction in losses from R. similis is that immature ginger is usually grown in rotation with
cassava and taro and high rates of poultry manure (15-20 t/ha) are applied before planting,
and in this farming system, nematode populations are not high enough to damage the
immature crop. If the nematode is introduced on infested planting material, small, shallow,
sunken, water-soaked lesions may develop on immature rhizomes, but the damage is
superficial and the crop is still marketable. R. similis is mainly a problem on crops that are
held over to supply seed for the following season. On infested farms, the nematode continues
to multiply as the season progresses and populations reach levels that may result in more than
50% of the seed ginger being rejected. Current work is focused on using tissue-culture to
provide nematode-free planting material, encouraging growers to dip their seed in hot water
using a well-established protocol (a temperature of 51ºC for 10 minutes), selecting fields to
5 th International Congress of Nematology, 2008 210