ABSTRACT
Nematicidal potentials
of aqueous extract of bitter leaf in the control of root knot nematodes on Okra
was evaluated at the Federal College of Agriculture, Ishiagu, Ebonyi State in
2017. Completely Randomized Design was used. There were four treatments of
different concentrations of aqueous extract of bitter leaf (T1 =
Bitter leaf at 50g/l, T2 = Bitter leaf at 100g/l; T3 = Bitter
leaf at 150g/l and T4 = Control 0g/l). Each was replicated five
times using sterilized soil in 10-liter buckets. Each plant at 3 weeks was
inoculated with about 4000 root-knot nematode eggs extracted from spinach plant
and identified. The results obtained after analysis of variance showed that
there were no mean plant height, mean stem girth, mean number of leaves, mean
number of fruits, mean weight of fresh fruits as well as on mean root gall
indices. There was significant difference (P < 0.05) among the treatments on
mean root weight of Okra plant. Treated plots however showed higher growth and
yield as well as had significantly (P < 0.05) higher root weight than the
control. The control however recorded higher mean gall index than all treated
plots. A higher concentration of bitter leaf aqueous extract is
recommended.
INTRODUCTION
1.0
BACKGROUND OF THE STUDY
Okra (Abelmoschus esculantus. Moench), belongs to the family Malvaceae.
It is a popular vegetable crop cultivated widely in the tropics and some parts
of the subtropics mainly for its fruits, which is used as a vegetable both in
the green and dried states. It is an important cash crop for small and marginal
farmers. This crop is suitable for cultivation as a garden crop as well as a
large commercial farms. It is grown commercially in India, Turkey, Weston
Africa, Ethiopia, Japan, Ghana, Cyprus and the southern United States. India ranks
first in the world with 3.5 million tonnes (70% of the total world production)
of okra produced from over 0.35milloins hectare land (Faostal, 2008).
Okra is an economically important vegetable crop known by
many local names in different parts of the world. It is called lady’s finger in
England, Gumbo in the United States of America, Guino-gombo in Spanish,
guibeiro in Portuguese and bhinidi in India, different names have been given in
different regional languages. The leaves are used in preparing medicament to
south or reduce inflammation (Olomilua 2007).
Okra requires a long warm and humid growing period. It
can be successfully grown in hot humid areas. It is sensitive to frost and
extremely low temperatures. For normal growth and development a temperature
between 240C and 280C is preferred. At 240C
the first flower bud may appear in sixth leaf axil (Peet et al, 2004).
About a hundred different
pest species have been recorded worldwide on okra crops (Peet, 2001). Some of
the major ones however, include nematodes, flea beetle (Podagrica), whitefly
(Bemisia Tabaci), cercospora blight (Cercospoca abelmoschus) (Kessel, 2003).
About 50% yield reduction
of okra in the tropics is caused by root-knot nematodes. The formation of galls
on the root of affected plant generally result in different symptoms of the
crop (Udo, 20040. Plant parasitic nematodes are of the genus Meloidogyne. There
are four different species of Meloidogyne pest that attack okra in this part of
the world. They include; M.jaumanica, M.auenaria, M.hapla and M. incomgnita
(Khani, 1997). Eisenback and trianta phyllon (1991), recommended the use of
botanical extracts like bitter leaf extract, basil extract, garlic, neem seed
extract and pogam cake in combating root-knot nematode infection on plants,
(Saravana priga and Sivakumar, 2005).
The use of mango leaves was
also reported to have special effect on Meloidogyne Species (Smith, 2002).
Root-knot nematodes live in the soil where they affect the root of okra plants
on it. Root knot nematodes are minute, worm-like animals which are very common
in the soil. They have a wide host range, causing problems in many annual and
perennial crops (Stirling etal, 2000).
The desire for the use of plant materials and other control methods apart from
the use of chemicals come up as a result of recent by amoration by way of
prohibition of nematicides that are less effective and of very high cost than
use of plant botanicals like Basil extract, garlic extract, neem seed extract c+
and ponm cake (Savanna- Priya and Siva- kumar, 2005). The use of bitter leaf
was also reported to have similar effect on Meloidogyne spp (Nair, 2002).
1.2 STATEMENT OF THE PROBLEM
Root-knot nematode (Meloidogyne spp) affects okra by
interfering with the nutrient uptake of the plant there by causing reduction of
the growth and yield. The effects of root-knot nematodes are also seen on both
primary and secondary roots of okra. Usually, conventional chemicals have
always been unavailable for use since their inception but it has been known
that the effect they have on crops have remained dangerous to human health, to
microorganism in the soil and when the rate of accumulation in soil is high it
can now make soil acidic or basic thereby affecting the soil nutrient composition
(Adegbite and Adesiyan, 2001).
1.3 OBJECTIVE OF THE STUDY
Broad objective
The broad objective of this
study is to determine the efficacy of the aqueous extract of bitter leaf in the
control of root-knot nematodes on okra.
Specific objective
i.
To
determine the efficacy of the bitter leaf extracts in the control of infections
by root-knot nematode on okra.
ii.
To determine
the effect of bitter leaf extract on the growth and yield of root-knot nematode
infested okra.
iii.
To
determine concentration of bitter leaf extract that can be applied for best
control of root-knot nematodes on okra.
1.4 Justification
of the study
Synthetic nematicides such as furadan,
nemagon, severally used to control root-knot nematode on okra have been found
to be costly, environmentally harzadous and not readily available. This
justifies the need to try out plant materials such as aqueous extract of bitter
leaf as alternative namaticide material to control nematodes.
This research work will
help the local farmers to understand the possibilities of using the aqueous
extract of bitter leaf that is not expensive, readily available and environmentally
friendly on the control of root-knot nematode on okra production in south
eastern Nigeria.
1.5 Duration
of the study
The experiment will start on March and end
in July 2017
DOWNLOAD FULL MATERIAL