Page 10 - 16 Cotton SA December 2018

RESEARCH

Evaluation of biological agents

and nematicides for control of root

knot nematodes on cotton in SA

S.C. Khuzwayo (ARC-IIC)

The importance of plant-parasitic nematodes as yield-limiting
pathogens of cotton has received increased recognition and attention

in the South African cotton producing areas in the recent past.

he root-knot nematodes, in particular row spacing of 20cm. A commercially available cotton
TMeloidogyne species, are by far the most cultivar, Candia BGRF was used for the experiment.
important nematode pests of cotton in South Africa. Standard nematicides were compared to each other,
Farmers use chemicals to or a combination of some of
control pests in order to the nematicides (Table 1).
increase the yield. Roots and soil samples were
collected at different cotton
Although the usefulness What are Nematodes?
of synthetic chemicals growth stages to determine
the
of
cannot be denied, the Nematodes are micro-scopic worm-
populations
negative environmental Meloidogyne spp. Seed
and human health effects like animals that feed primarily on
cotton yield was a determined
can also not be ignored. the roots of cotton plants. Plant
at the end of the season. A
Government restrictions parasitic nematodes puncture root
students t-test was used to
on the use of chemicals analyze the data, by
by farmers and the cells with their stylets and withdraw
calculating the Least Signi-
ficant Differences between
increasing costs and nutrition from the host plant.
hazards of applications treatments (p < 0.05).
have stimulated research
towards the development
of cheaper and more The results revealed that all
effective control measures that can be applications had a significantly (p < 0.05) lower
recommended. The use of biological control agents number of root-knot nematode populations in the soil
to manage plant parasitic nematodes may compared to the untreated control. Plots that were
provide the best alternative to pesticides. treated with Nemacur showed a lower number
The objective of this study was to of root-knot nematodes on the roots
evaluate efficacy of biological and (Figure 1). The control had the lowest
synthetic nematicides in con- significant seed cotton yield of 2.7
trolling plant-parasitic nema- t/ha compared to Trans-
tode species on cotton under former_Nemacur, Nemacur®,
field conditons. Vydate ®SL and FirstBase®2.
The combination of Transformer
+ Nemacur had the highest
A field experiment was significant seed cotton yield of
conducted in Douglas, 5.8 t/ha compared to
Northern Cape and the trial Poncho®VOTiVO®, Trans-
was conducted during the former-SA_CropBioLife®,
2017/18 season. The trial Velum®Prime 500 SC,
was planted in October AVICTA® 500FS and an
2017 under irrigation. The Untreated Control (Table 1).
experiment comprised of a These yields were above the
randomized block design with average yield of 4464 t/ha
11 treatments, replicated 4 estimated in South Africa for the
times, three rows per block, 2017/18 season.
which were 3m long and an inter

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