Management of root-knot nematodes (meloidogyne spp) tnokra (abelmoschus esculentus (l) moench) using nematode suppressive crops and organic soil amendments
Abstract
This study was undertaken to develop an intergraded root- knot nematode management
strategy in okra by using crop rotation of nematode suppressive crops and incorporation of
organic amendment in to the soil. Several cereals and legume crops were screened in a
greenhouse and okra was used as a control. The greenhouse experiment revealed that maize,
sorghum, millet and guwar were suppressive to root-knot nematode. Pigeon pea was
moderately susceptible while cowpeas and green grams were susceptible.
Aller the greenhouse experiment, three IIJUl/.e varieties (bubycoru. swectcornund pioneer-
Ph3253) and guwar were selected for a repeat experiment under field conditions in rotation
with okra. Results showed that guwar and swcctcorn were the 1110stsupprcssi vc followed by
maize cv Pioneer (Ph3253) and Babycorn.
Based on the results of greenhouse experiments, four crops namely guwar, sweet com, baby
com and maize cv Pioneer (Ph3253) were selected for their effectiveness in suppressing rootknot
nematodes in rotations with okra. The findings from this study demonstrate that one
season rotation of these suppressive crops with okra was not enough to reduce nematodes to
levels below economic damage threshold because nematode populations quickly build up
when okra was planted immediately after these crops. Rotation of sweetcom followed by
okra appeared to be more effective in reducing nematodes build up as it recorded least
population build up followed by guwar, maize cv Pioneer (3253) and Baby corn in that
order.
Farmyard manure was incorporated into the soil before planting okra after these selected
crops to determine the effect of combining rotation- of suppressive crops and organic
amendment in root- knot nematode management.
There was clear evidence that combining organic amendment and crop rotation incorporating
nematodes suppressive crops was more effective in reducing nematode population in the soil
than rotation alone. Reduction of the Meloidogyne population in the soil was higher in soils
where guwar was planted followed by okra indicating that this is a good combination in rootknot
nematode management. Among the rotation cycles tested was sweet corn in the first
season followed by okra in the next season.
This study shows that integrated management approach in root knot nematodes management
is the way forward because it is more effective and sustainable in the long run. Organic
manure (farmyard manure) incorporated in guwar and rotated with sweet corn can be
recommended to farmers as rotation crops because of their performance in this study. Also
because they mature fast and have ready market. Once adopted, this integrated approach will
result ill increased yields and income to smallholder farmers. It is affordable, easy to apply as
well as environment friendly and hence sustainable over a long period of time. Farmers will
reap multiple benefits.
Citation
Master of Science degree in crop protectionPublisher
University of Nairobi Department of plant science and crop protection