ABSTRACT
A field trial was undertaken to study the efficacy of plant extracts in the management of rice stem borers at Michael Okpara University of Agriculture, Umudike, Southeastern Nigeria during 2016 and 2017 cropping seasons. The experiment was laid out as 3 x 4 split plot arranged in Randomized Complete Block Design (RCBD) with three replicates. The main plot contained varieties of rice: FARO 44, FARO 52, Ovuku and the sub plot treatments consisted of 5 % each of aqueous extracts of Jatropha curcas L., Ageratum conyzoides L., synthetic insecticide (Furadan 4 G) and the untreated control. Furadan 4 G was applied at 50 g per square metre. The treatments were applied at the tillering stage and booting stage. The results showed that Furadan 4 G and the plant extracts significantly (P<0.05) reduced the percentage dead hearts and whiteheads caused by stem borers compared to untreated control. The yield of the rice in the two years trials were significantly higher (P<0.05) in Furadan 4 G treated plants followed by J. curcas and A. conyzoides than the control. FARO 44 and FARO 52 varieties were less susceptible to the stem borers and had higher grain yield than Ovuku variety. The results suggest that aqueous extracts of J. curcas and A. conyzoides can be suitable alternative to synthetic insecticides for controlling rice stem borers without altering the agro-ecosystem. Incorporating 5 % aqueous extracts of J. curcas and A. conyzoides into lowland rice production in the area will help to mitigate stem borers attack and improve crop yield. FARO 44 and FARO 52 varieties which demonstrated less susceptibility to the stem borers and higher yield should be adopted by farmers to produce bulk of rice.
TABLE OF CONTENTS
Title Page i
Declaration ii
Certification iii
Dedication iv
Acknowledgments v
Table of Contents vi
List
of Tables ix
Abstract xi
CHAPTER 1: INTRODUCTION 1
1.1 Objective of the Study 3
CHAPTER 2: LITERATURE REVIEW 4
2.1 Origin of Rice 4
2.1.1 History of rice types in Nigeria 4
2.1.2 Geographical distribution of rice 6
2.2 Rainfed Lowland Rice 14
2.3 Morphology of Rice 15
2.3.1 Vegetative phase 15
2.4 Reproductive Phase 17
2.4.1 Nutritional value of rice 18
2.4.2 Health benefits of rice 18
2.5 Rice Ecology 19
2.6 Recommended Lowland Varieties 20
2.6.1 FARO 44 (SIPI-692033) 20
2.6.2 FARO 52 WITA 4 21
2.7 Rice Production Methods 21
2.7.1 Direct-seeded rice 22
2.7.2 Direct seeding on dry seed bed or dry direct
seeded rice 23
2.8 Insect Pests
in Rice Production 23
2.8.1 Stem borers of rice and their economic
importance 25
2.8.2 Chilo zacconius Bleszynski, African striped rice borer
(Lepidoptera: Pyralidae) 26
2.8.3 Maliarpha separatella Ragonot
, African white borer
(Lepidoptera: Pyralidae) 27
2.8.4 Sesamia calamistis Hampson, African pink borers
(Lepidoptera: Noctuidae) 28
2.8.5 Diopsis longicornis Macquart, Stalk-eyed fly (Diptera: Diopsidae) 29
2.9 Management of Rice Stem Borer 30
2.10 Chemical Insecticides for the Management of
Rice Stem Borer 32
2.11 Botanical Products for the Management of Rice Stem Borer 37
CHAPTER 3: MATERIALS AND METHODS 45
3.1 Experimental Site 45
3.2 Soil Sampling and Analysis 47
3.3 Planting Materials 48
3.4 Field Preparation and
Experimental Design
48
3.5 Application of Treatments 49
3.5.1 Preparation of aqueous extract of J. curcas 49
3.5.2 Preparation of aqueous extract of A. conyzoides 49
3.6 Data Collected 50
3.7 Data Analysis 51
CHAPTER 4: RESULTS AND DISCUSSION 52
4.1 Results 52
4.1.1 Efficacy of plant extracts and furadan 4 G
on mean percentage dead
heart 55 DAP in
2016 and 2017 planting seasons. 52
4.1.2 Efficacy of plant extracts and furadan 4 G
on mean percentage dead
heart 70 DAP in
2016 and 2017 planting seasons. 54
4.1.3 Efficacy of plant extracts and furadan 4 G
on mean percentage
whiteheads during 2016
and 2017 planting seasons. 57
4.1.4 Efficacy of plant extracts and furadan 4 G
on mean number of larvae per
rice stem during 2016 and 2017
planting seasons. 59
4.1.5 Efficacy of plant extracts and furadan 4 G
on mean number of panicle per
rice plant during 2016 and 2017
planting seasons. 61
4.1.6 Efficacy of plant extracts and furadan 4 G
on mean number of tillers
per plant stem 55
DAP during 2016 and 2017 planting seasons. 63
4.1.7 Efficacy of plant extracts and furadan 4 G
on mean number of
tillers per rice
plant 70 DAP during 2016 and 2017 planting seasons. 65
4.1.8 Efficacy of plant extracts and furadan 4 G
on mean grain yield of
rice varieties
during 2016 and 2017 planting seasons. 67
4.2 Discussion 69
4.2.1 Efficacy of aqueous plant extracts and
furadan 4 G in the management
of rice stem
borers 69
4.2.2 Efficacy of plant extracts and furadan 4 G on
dead heart and
whiteheads of lowland
rice 72
4.2.3 Efficacy of plant extracts and furadan 4 G on
yield of lowland rice 75
CHAPTER 5: CONCLUSION AND RECOMMENDATIONS 78
5.1 Conclusion 78
5.2 Recommendations 78
REFERENCE 80
LIST
OF TABLES
Rice
growing systems in the North-east zone 8
Rice growing systems in the North-west zone 9
Rice
growing systems in the South-center zone 10
Rice
growing systems in the South-east zone 11
Rice
growing systems in the South-south zone 12
Rice
growing systems in the South-west zone 13
Agrometerological
data of the experimental site for
2016 and
2017 46
Soil physico-chemical properties of the
experimental sites in
2016 and 2017 cropping seasons 47
Efficacy
of aqueous extracts and furadan 4 G against rice stem
borer on lowland varieties of rice during 2016 and 2017 planting
seasons assessed from dead heart (% DH) 55
DAP
53
Efficacy
of aqueous extracts and furadan 4 G against rice stem borer
on
lowland varieties of rice during 2016 and 2017 planting seasons
assessed
from dead heart (% DH) 70 DAP
56
Efficacy
of aqueous extracts and furadan 4 G on reduction of
whiteheads
(% WH) 85 DAP in lowland varieties of rice during 2016
and
2017 planting seasons. 58
Efficacy
of aqueous plant extracts and furadan 4 G on reduction of
larvae
number per rice stem in lowland varieties of rice during 2016
and
2017 planting seasons.
60
Efficacy
of aqueous plant extracts and furadan 4 G on the number
of
panicles per stem on lowland varieties of rice during the 2016
and
2017 planting seasons.
62
Efficacy
of aqueous plant extracts and furadan 4 G on number of
tillers
per rice plant 55 DAP during the 2016 and 2017 planting seasons 64
Efficacy
of aqueous plant extracts and furadan 4 G on number of
tillers
per rice plant 70 DAP during the 2016 and 2017 planting seasons 66
Efficacy
of aqueous plant extracts and furadan 4 G on lowland varieties
of
rice against rice stem borers and effects on yield in tonnes per hectare
during
the 2016 and 2017 planting seasons
68
CHAPTER
1
INTRODUCTION
Rice
(Oryza sativa L.) is
one of the major diet of over half of the world’s population. Globally,
production of rice is ranked third after wheat and maize while in Nigeria is
ranked sixth after sorghum, millet, cowpea, cassava and yam (Bandyopadhay and
Roy, 1992; Dauda and Dzivama, 2004; Olaleye et al., 2004). It is grown
in all agro ecological zones in Nigeria. Nigeria is the largest producer of
rice in West Africa with average of 3.2 mn tonnes of paddy rice (USDA, 2002,
Nwilene et al., 2008). The global rice production is estimated at
4.5 mn tonnnes annually which has an average yield of 4.25 mn stonnes per
hectare (Fazlollah et al., 2011). In
Nigeria land under rice cultivation and production is increasing every year,
from 1.61 mn hectares in 2005/2006 to 2.0 mn hectares in 2009/2010 and
production also moved from 3.3 mn kgha-1 in 2005/2006 to 4.1 mn kgha-1
in 2009/2010. Currently, rice area and production have increased to 2.5
mn hectares and 2.7 mn tonnes in 2016/2017 (Ibrahim et al., 2011). An average Nigerian consumes about 24.8 kg of rice
per year (Uche et al. 2016).
Although,
rice is grown virtually in all agroecological zones of Nigeria, rice production
is still far below the potentials and domestic needs. One of the major
constraint for the low yield of rice in Nigeria is attacked by insect pests
(Imolehin and Ukwungwu, 1992). Rice plant is attacked by a large number of
insect pests in West Africa (Heinrichs and Barrion, 2004). Among all the insect
pests of rice, stem borers have been reported to cause greater damage to rice
plants. There are about 20 species of stem borers identified which are
destructive to rice plant worldwide. However, only four species are of economic
importance in Nigeria. These include Chilo
zacconius Bles, Diopsis
macropathalman Daman, Maliarpha separatella
Rog, and Sesamia calamistis Hampson
(Heinrichs and Barrion, 2004). The spreading and copiousness of these species
vary among rice ecosystems within a given location. For example; M. separatella and Chilo spp occur in all climatic zones in West Africa but they are
more abundant in the rain fed lowland and irrigated ecosystems than in the
uplands and are the most abundant stem borer species in the mangrove swamps
while Sesamia spp prevail in the
uplands (Heinrichs and Barrion, 2004).
These
borers attack rice plant at all growth stages from vegetative stages to
reproductive stage. In the vegetative stage of the rice plant, stem borers’
larvae bore at the base and feed on the leaf sheath initiating broad
longitudinal whitish areas at the feeding sites which prevents the central leaf
whorls from unfolding, resulting in brownish colour and death, leading to
condition known as “dead hearts”. Damaged shoot do not produce a panicle and
thus produce no grain. During the
reproductive stage of the rice plant (panicle initiation to milk grain), the
stem borers’ bore through the upper nodes and feed toward the base causing
serious damage on the developing panicle at its base. As a result, the panicle
is unfilled and whitish in colour; the condition known as ‘whitehead’ (WH)
rather than filled with grain and brownish colour (Amaugo and Emosairue, 2003;
Mahmood-ur-Rehman et al., 2007).
Report has shown that rice stem borers cause yield losses ranging from 30 to 80
%. A loss of 100 % has been recorded in worst affected fields in Nigeria
(Imolehin and Ukwungwu, 1992). In many parts of Africa the borers destroy 30 %
-50 % of plant tillers during the wet cropping season thereby compromising the
whole harvest (Dakaouo et al., 1991).
In
the past emphasis has been on the use of synthetic insecticides for the control
of stem borers and successful control of it has been achieved through the use
of a number of conventional insecticides (Hill and Waller, 1988; Amaugo and
Emosairue, 2003). However, the indiscriminate use of insecticides has caused a
number of adverse side effects such as the emergence of resistant species of
insects, environmental pollution and hazards to farmers (Hassall, 1990). In
addition, insecticides are known to undermine the ecosystem for sustainable production
of rice and are generally not affordable to farmers. In order to relieve
growing public fears regarding the effects of synthetic insecticides on human
health and environmental impact much attention has been given to botanical
pesticides in the recent decades. Botanicals are considered environmentally
friendly; besides, this method does not only reduce application of synthetic
insecticides, but also reduce the cost of pest management, which is an
important factor for farmers in developing countries. Furthermore, in recent
years there has been an increased interest in the use of biopesticides
particularly in cropping system where the use of natural enemies are being
emphasized as a major component of integrated pest management (Rausell et al., 2000). Use of these natural
compounds in place of synthetic insecticides can reduce environmental
pollution, preserve non-target organisms and prevent insecticide induced pest
resurgence.
Bioinsecticides
are rarely as effective as chemicals in their crude extract form. The
efficacies of botanicals are largely demonstrated in insect management and have
been encouraged for use by resource poor farmers (Huang et al., 2000; Dal Bello et
al., 2001; Taponjou et al.,
2002). Plants produce a diversity of biologically active substances that affect
the growth and development of other organisms and can provide protection
against the herbivores. These plant products discourage or prevent an attack
from the non-adapted organisms and play an important role in the ecology and
physiology of phytophagous insects (Sukumar, 1993). Shukle et al. (1992) evaluated the field efficacy of 3 % neem oil solution
and 5 % neem seed kernel extract and reported a significant reduction in the
populations of the green leaf hopper, the white backed plant hopper and the
leaf folder in treated plots of rice when compared with the untreated plots.
Amaugo and Emosaire, (2003) evaluated aqueous and acetone extracts of seed
kernels of neem (Azadirachta indica
A. Juss); nutmeg (Monodora myristica
(Gaertn.) Dunal; physic nut (Jatropha
curcas. L.); castor-oil (Ricinus
communis L.); synthetic insecticide (Monocrotophos) and the untreated check
to control rice stem borer and reported that neem seed and physic nut seed
kernel extracts were statistically better than other plant extracts in
controlling stem borers and influencing yields of the crop. This research
evaluated the field effectiveness and performance of two indigenous medicinal
plant extracts (J. curcas and Ageratum conyzoides) for the control of lowland rice stem borers and the
impact on the yield of different varieties of rice crop.
1.1 OBJECTIVES OF THE STUDY
The following are the objectives of this research:
I.
to evaluate the efficacy of aqueous J. curcas and A. conyzoides in the
management of rice stem borer and yield of rice.
II.
to determine suitable rice variety in this
agroecological zone
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