Evaluation Of Maize Varieties And Accessions For Resistance To Insect Pests And Toxicity Of Ordeal Bark Solvent Extracts To Sitophilus Zeamais Motsch. (Coleoptera: Curculionidae)

ABSTRACT

Studies were carried out at Nsukka to evaluate maize varieties and accessions for resistance to insect pests and toxicity of Ordeal bark solvent extracts to Sitophilus zeamais Motsch. The studies were carried out in Departments of Crop Science, Civil, Agricultural and Bioresources Engineering, University of Nigeria, Nsukka (UNN). The proximate and phytochemical analyses for all maize accessions were carried out in the Department of Food Science and Technology Laboratory of Ahmadu Bello University (ABU) Zaria in collaboration with International Institute of Tropical Agriculture (IITA), Ibadan.  A total of twenty-one maize accessions were used, which included (a) three local landraces (Nsukka-pink, Enugu-Ezike and Kagoro white from locations as their names imply, (b) two hybrids  (Sammaz -15 and 16) and (c) sixteen open pollinated varieties (Sammaz -11, 14, 17, 18, 20, 26, 27, 28, 29, 31, 32, 33, 34, 35, 37, and Oba Super 2). Both hybrids and open pollinated varieties were obtained from Institute of Agricultural Research (IAR) Samaru Zaria in collaboration with International Institute for Tropical Agriculture (IITA), Ibadan. The results indicated that the various maize accessions differed significantly in their relative susceptibility to S. zeamais damage. Sammaz -35 with susceptibility index (SI) of 5.33 was moderately susceptible (MS), Sammaz -26 (SI = 3.47) moderately resistant (MR), while Sammaz -32 (SI = 1.79) was resistant (R) to maize weevil damage. Proximate analysis showed that Sammaz- 27, 32, 34, 35, 17 and 18 contained significantly (p<0.05) higher moisture (3.84 %), fat (4.18 %), ash (2.04 %), protein (8.76 %), carbohydrate (85.36 %) and fibre (1.12 %), respectively compared to other varieties and accessions. Lectin content of 0.006 mg/100 g maize was present in each of Sammaz- 14, 18 and 29 and were significantly (p<0.05) higher than those of other varieties and accessions. Sammaz -11, 37, 15 and 27 were significantly (p<0.05) higher in phytate (0.072 mg/100 g maize), oxalate (0.70 mg / 100 g maize), tannin (0.48 mg/ 100 g maize) and trypsin inhibitor (0.06 mg/ 100 g maize) contents, respectively relative to other accessions. Irrespective of year of planting, stemborer damage on maize stalks were significantly (p<0.05) higher in July than in May planting. Sammaz -32 sustained higher borer damage relative to other varieties and accessions. Conversely, Sammaz- 28 harboured significantly (p<0.05) more earworm populations than other varieties / accessions, year and season of planting, notwithstanding. The organic solvents (n-hexane and petroleum-ether) extracts of ordeal tree stembark caused 100 % adult weevil mortality, F₁ and F₂ suppression, and offered complete protection against grain damage and weight loss caused by maize grain weevil. On the other hand, the organic solvents caused complete loss of viability of seeds in all accessions. The path coefficient analyses revealed that the highest direct negative effects on susceptibility were exhibited by % tannin (-0.4127), fat (-0.3698), grain width (GW) (-0.7332), extension (-0.7018) and compressive strength (CS) (-0.8282). The highest direct positive effect on cob weight (CW) was observed in grain weight (GW) (0.7301) while the highest negative direct effect on cob weight (CW) was observed in percentage infestation (PI) (-0.37745) of stem borers.

 

 

 

 

TABLE OF CONTENTS

Cover page      –           –           –           –           –           –           –           –           –           –           i

Declaration      –           –           –           –           –           –           –           –           –           –           ii

Approval Page                        –           –           –           –           –           –           –           –           –           iii

Certification Page       –           –           –           –           –           –           –           –           –           iv

Dedication      –           –           –           –           –           –           –           –           –           –           v

Acknowledgments      –           –           –           –           –           –           –           –           –           vi

Table of Content         –           –           –           –           –           –           –           –           –           viii

List of Tables –           –           –           –           –           –           –           –           –           –           xiii

List of Figures             –           –           –           –           –           –           –           –           –           xvii

List of Plates   –           –           –           –           –           –           –           –           –           –           xviii

Abstract          –           –           –           –           –           –           –           –           –           –           xx

INTRODUCTION    –           –           –           –           –           –           –           –           –           1

Objectives       –           –           –           –           –           –           –           –           –           –           2

LITERATURE REVIEW               –           –           –           –           –           –           –           3

Maize Taxonomy, Age, Origin, Distribution and Production –          –           –           –           3

Trends of maize production in Nigeria-          –           –           –           –           –           –           5

The cornbelt of Nigeria –         –           –           –           –           –           –           –           –           5

Causes of post-harvest losses in maize –         –           –           –           –           –           –           10

Ways of reducing post-harvest food losses in maize –            –           –           –           –           11

Susceptibility of maize grains to storage pest –           –           –           –           –           –           12

Sources of storage insect pest infestation –     –           –           –           –           –           –           12

Nature of damage or loss on maize caused by storage insect pests    –           –           –           13

Quantity of storage losses of maize by pest in the tropics      –           –           –           –           13

Biochemical composition of maize –   –           –           –           –           –           –           –           14

Anti-nutrient in cereal grain –  –           –           –           –           –           –           –           –           14

Positive effects of phytochemicals in human health and nutrition     –           –           –           15

Use of plant materials for insect pest control in storage         –           –           –           –           18

Use of plant oils, liquid and powdery extracts in insect pest control in storage        –           21

Ordeal tree (Erythrophleum africanum Harms)          –           –           –           –           –           23

Corn stalk borers –       –           –           –           –           –           –           –           –           –           26

Biology and ecology of the African maize stalk borer (Buseola fusca, Fuller)          –           27

Maize Earworms –       –           –           –           –           –           –           –           –           –           28

Genetics and biochemistry of insect resistance in maize –      –           –           –           –           28

Maize-insect tritrophic interactions –  –           –           –           –           –           –           –           30

Transgenic corn borer and corn rootworm resistant maize varieties   –           –           –           31

Transgenic avidin maize –       –           –           –           –           –           –           –           –           31

Advantages and Disadvantages of using Bt-Hybrids –          –           –           –           –           32

Mean and standard deviation of data –          –           –           –           –           –           –           34

Standard Deviation     –           –           –           –           –           –           –           –           –           35

Correlation Matrix      –           –           –           –           –           –           –           –           –           35

Path analysis, path diagrams and path tracing rules   –           –           –           –           –           36

Seed science and seed germination test –       –           –           –           –           –           –           39

MATERIALS AND METHODS    –           –           –           –           –           –           –           41

Field screening of maize accessions for stalk borer Resistance          –           –           –           41

Meteorological data collection –         –           –           –           –           –           –           –           43

Assessment of maize stem borers attack –      –           –           –           –           –           –           43

Screening test for maize seed / grain susceptibility / resistance to maize weevil

damage            –           –           –           –           –           –           –           –           –           –           47

 

Pre-laboratory Screening Germination Test –  –           –           –           –           –           –           48

Screening of maize varieties / accessions for susceptibility / Resistance to S.zeamais –         48

Biochemical analysis of ordeal tree stembark –           –           –           –           –           –           51

Effect of Ordeal tree stem bark extracts and Resistance/susceptibility

of the maize Accessions / varieties on the Infestation of S. zeamais    –           –           51

 

Evaluation of solvent extracts of Ordeal tree stem bark and             synthetic insecticide on

mortality of adult  S. zeamais infesting resistant / susceptible

maize varieties   –           –           –           –           –           –           –           –           –           52

 

Evaluation of solvent extracts of Ordeal tree stem bark and synthetic insecticide on

progeny emergence of S. zeamais on resistant / susceptible stored maize

varities / accessions        –           –           –           –           –           –           –           –           53

 

Evaluation of solvent extracts of Ordeal tree stem bark and synthetic insecticide on

grain damage and weight loss caused by S. zeamais to resistant / susceptible

of stored maize varieties / accessions    –           –           –           –           –           –           53

 

Evaluation of solvent extracts of Ordeal tree stem bark and synthetic insecticide on

germination of resistant / susceptible of stored maize varieties / accesstions –             53

 

Evaluation of solvent extracts of Ordeal tree stem bark and synthetic insecticide

shelf life / longetivity for 4 weeks against insect pest of stored maize.         –           54

 

 

Determination of the Physical and Mechanical properties responsible for Resistance /

Susceptiblity to S.zeamais–        –           –           –           –           –           –           –           54

 

Determination of the proximate composition of the maize accessions/varieties         –           56

Some maize anti-nutrients and their determination –  –           –           –           –                       61

 

RESULTS –   –           –           –           –           –           –           –           –           –           –           64

 

 

Meteorological data: Monthly mean rainfall, temperature and relative humidity for

2012 and 2013 cropping seasons –        –           –           –           –           –           –           64

 

Effect of two planting dates on incidence of stalk borers, earworms on yield

parameters of maize varieties / accessions in 2012 and 2013 cropping seasons –   66

 

Comparison of effects of month of planting and year on stalk borer, earworm

infestations and yield parameters of maize      –           –           –           –           –           71

 

The effect of interaction of planting dates on stalk borer / earworm infestations on

yield parameters of maize accessions / varieties in 2012 and 2013 cropping

seasons   –           –           –           –           –           –           –           –           –           –           73

 

Combined effect of planting dates, stalk borer / earworm infestation on yield

parameters of maize varieties / accessions in 2012 and 2013 cropping

seasons   –           –           –           –           –           –           –           –           –           –           81

Comparison of month of planting, stem borer / earworm infestation and yield

Parameters of maize accessions / varieties in 2012 and 2013 cropping seasons –         85

 

Comparison of month of planting, stem borer / earworm infestation and yield

parameters of maize accessions / varieties in 2012 and 2013 cropping seasons –          87

 

Screening maize accessions / varieties for susceptibility to Sitophilus zeamais Mot.

infestation –       –           –           –           –           –           –           –           –           –           92

 

Correlation matrix of susceptibility index and weevil adult mortality, adult emergence,

50% adult emergence time of S. zeamais, % damage and % weight loss of

maize grains –     –           –           –           –           –           –           –           –           –           94

 

Direct and indirect effect of S. zeamais performance on susceptibility index (SI) of

maize varieties – –           –           –           –           –           –           –           –           –           96

 

Physical attributes of maize accessions / varieties and their respective susceptibility

indices to S. zeamais –   –           –           –           –           –           –           –           –           99

 

The correlation coefficient of five physical characters evaluated for twenty accessions

/ varieties of maize –     –           –           –           –           –           –           –           –           101

 

Path coefficient analysis of six physical properties of twenty maize accessions /

varieties and their direct and indirect effects on maize susceptibility index

to S. zeamais –  –           –           –           –           –           –           –           –           –           103

 

Cluster analysis of the physical attributes of screened maize accessions / varieties – 107

 

Effect of mechanical attributes of maize accessions/varieties on their susceptibility

To S. zeamais –  –           –           –           –           –           –           –           –           –           109

 

The correlation efficient of eight mechanical properties of maize and its susceptibility

to maize weevil (S. zeamais) –   –           –           –           –           –           –           –           112

 

Path coefficient analysis of susceptibility index of 8 mechanical properties of maize

accessions / varieties to S. zeamais –      –           –           –           –           –           –           114

 

Cluster analysis of the mechanical attributes of screened maize accessions / varieties –        119

 

Proximate composition of different accessions / varieties of maize   –           –           –           121

 

Correlation matrix of susceptibility index of maize to S .zeamais and proximate

qualities –          –           –           –           –           –           –           –           –           –           123

 

Direct and indirect effects of the proximate contents of maize on its susceptibility

index     (SI) to S. zeamais –      –           –           –           –           –           –           –           125

 

Anti-nutrients composition (mg / 100 g) of different maize accessions / varieties     –           128

 

Correlation matrix of susceptibility index of S. zeamais infestation on maize and

anti-nutrient effects –     –           –           –           –           –           –           –           –           130

 

Path Coefficient analysis of correlation matrix of susceptibility index of S. zeamais

infestation on anti-nutrient components in maize –       –           –           –           –           132

 

Biochemical analysis of ordeal tree (Erythrophelum africanum Harms) stem bark    –           135

 

Biochemical analysis of two stalks of maize varieties (Sammaz-14 and 28) adjudged

to be moderately resistant  (R) and moderately susceptible (MS) respectively –          136

 

Effect of solvent extracts concentrations of ordeal tree stem bark on mortality of

adult S. zeamais 24, 48, 72 hrs and 7^th day post-treatment –   –           –           –           137

 

Progenies (F₁ and F₂) adult emergence of S. zeamais on susceptibility status of maize-       143

 

Effects of solvent extracts concentrations of Ordeal tree stem bark on percentage

damage caused by S. zeamais on susceptibility status of maize –        –           –           146

 

Effects of solvent extracts concentrations of ordeal tree stem bark on percentage

weight loss caused by S. zeamais on susceptibility status of maize      –           –           148

 

Effects of ordeal tree stem bark extraction solvent concentrations shelf life /

longevity at weekly intervals on adult mortality of S. zeamais 24, 48, 72 hours

and 7^th day after exposure to the extract          –           –           –           –           –           150

 

Effects of ordeal tree stem bark extraction solvent concentrations shelf life /

longevity at weekly intervals on adult F₁ and F₂ emergence of

1. S. zeamais after treatment      –           –           –           –           –           –           –           156

 

Effects of ordeal tree stem bark extraction solvent concentrations shelf life /

longevity at weekly intervals on percentage grain damage by S. zeamais

post-treatment  –           –           –           –           –           –           –           –           –           160

 

Effect of ordeal tree stem bark extraction solvent concentrations shelf life /

longevity at weekly intervals on germination weight loss of maize grains

caused by S. zeamais after treatment. –           –           –           –           –           –           162

 

Effects of ordeal tree stem bark extraction solvent concentrations shelf life /

longevity at weekly intervals on percentage seed germination count

after treatment   –          –           –           –           –           –           –           –           –           164

 

Correlation matrix of yield parameters of maize infested by stalk borers and

earworms in May 2012 and 2013 cropping seasons –    –           –           –           –           166

 

Path analysis of direct and indirect effects of yield parameters of maize infested by

stalk borers and earworms in May 2012 and 2013 cropping seasons    –           –           168

 

Cluster analysis of maize accessions / varieties with similarities in yield parameters

affected by maize stem borers and earworms infestation in May 2012 and 2013

cropping seasons            –           –           –           –           –           –           –           –           173

 

correlation matrix of stem borers and earworms factors on yield of maize in

May 2012 and 2013 cropping seasons             –           –           –           –           –           –           175

 

Path analysis of stem borer and earworms activity factors on yield of maize in

May 2012 and 2013 cropping seasons –            –           –           –           –           –           177

 

Mean and standard deviations of some maize stalk borer and earworm activity effects

used in the classification of twenty-one accessions/varieties of maize into four

clusters for May 2012 and 2013 cropping seasons –     –           –           –           –           182

 

Correlation matrix of some crop parameters affecting yield under natural infestations

by stalk borers and earworms in July 2012 and 2013 cropping seasons           –           184

 

Direct and indirect effects of maize stalk borers and earworms infestation on

parameters of maize planted in July 2012 and 2013 cropping seasons –           –           186

 

Mean and standard deviations of some maize parameters, similarities and effects

used in the classification of twenty-one accessions / varieties into four clusters

for July 2013 and 2013 cropping seasons         –           –           –           –           –           191

 

Correlation matrix of nine insect pests activity factors on maize yield, under natural

infestations by stalk borers and earworm for July 2012 and 2013

cropping seasons            –           –           –           –           –           –           –           –           193

 

Path coefficient analysis of eight insect pests activity factors on maize yield under

natural    Infestations by stalk borers and earworms in July 2012 and 2013

cropping seasons.           –           –           –           –           –           –           –           –           195

 

Cluster analysis of maize stalk borer and earworm effects on twenty-one

accessions / varieties grouped into cluster for July 2012 and 2013

cropping seasons            –           –           –           –           –           –           –           –           201

 

DISCUSSION           –           –           –           –           –           –           –           –           –           203

 

Experiment 1: Screening maize accessions / varieties for Susceptibility / Resistance

          to S. zeamaisAttack under laboratory conditions         –           –           –           –           203

 

Experiment 2: Physical attributes of maize accessions / varieties and effects on

          maize grain Resistance to S. zeamais    –           –           –           –           –           –           204

 

Experiment 3: Mechanical attributes of maize accessions / varieties and effects on

          maize grain Resistance to S. zeamais –  –           –           –           –           –           –           205

 

Experiment 4: Evaluation of the proximate compositions of maize accessions /

          varieties and Maize grain Susceptibility /Resistance to S. zeamais  attack       –           205

 

Experiment 5:  Evaluation of anti-nutrients of maize accessions / varieties and

          grain Susceptibility / resistance to S. zeamais attack     –           –           –           –           206

 

Experiment 6:  Evaluation of the efficacy and shelf-life/longevity of solvent

          extracts of Ordeal tree stem bark and maize grain degree of resistance against

1. zeamais attack –           –           –           –           –           –           –           –           207

 

Experiment 7: Correlation and path coefficient analysis of crop parameters

          affecting maize yield under natural infestations by stalk borers and earworms

in July 2012 and 2013 cropping seasons           –           –           –           –           –           209

 

Experiment 8: The correlation and path analysis of stalk borers and earworms

          activity factors on yield of maize in May and July 2012 and 2013

cropping seasons –         –           –           –           –           –           –           –           –           209

 

CONCLUSION AND RECOMMENDATION                –           –           –           –           211

REFERENCES        –           –           –           –           –           –           –           –           –           212

PLATES        –           –           –           –           –           –           —          –           –           –           230

 

 

 

 

CHAPTER ONE

INTRODUCTION

Maize (Zea mays L.) is the most important crop in sub-Saharan Africa (IITA, 2009; Anon., 2011). It is a staple food for an estimated 50 % of the population. It is an important source of carbohydrate, protein, iron, vitamin B and minerals. Africans consume maize in a number of ways (porridges, pastes and drinks). Green maize, fresh on the cob, is eaten baked, roasted or boiled. Every part of the maize crop has economic value. The grain, leaves, stalk, tassel, and cob can all be used to produce a large variety of food and non-food products. In sub-Saharan Africa, maize is mostly grown by small-scale farmers, generally for subsistence as part of mixed agricultural systems (Anon., 2012; IITA, 2009).  The United States of America (USA) is the largest  world producer of the crop. Other leading producers include Europe, Asia and Latin America (Philip et al., 2006).

Maize has been the diet of Nigerians for centuries. It started as a subsistence crop and has gradually become more important. In Nigeria, maize has now risen to a commercial crop on which many agro-based industries depend on as raw material (Anon., 2012). Lale (1995) reported that more than 200 species of insects have been recorded as damaging the maize plant world-wide and that the insect pest of the genus Sitophilus in the family Curculionidae contains three of the world’s most destructive pests of stored cereal grains, of which two occur in the tropics. The tropical species attacking stored cereals ( maize, rice, sorghum, millet and wheat) are Sitophilus zeamais and Sitophilus oryzae. Their temperate counterpart is Sitophilus granarius. Maribet and Aurea (2008) reported that in stored maize, heavy infestation by S. zeamais may cause weight losses of as much as 30 – 40 %, although losses are commonly 4 – 5 %. Stemborers are the most important insect pest of maize in sub-Saharan Africa causing a yield loss that vary between 20 and 70 %  in the field (Ajala et al., 2001), while Gabrielle et al. (2010) attributed a yield loss as high as 40 % only to Busseola fusca. The Anon. (2011) attributed a yield loss of 20 to 40 % to stermborers. The most important are the African maize stalkborer (Buseola fusca) and the spotted stemborer (Chilo partellus). The pink stalkborer (Sesamia calamistis and the sugarcane stalkborer Eldana saccharina) are of minor importance (Schulthess and Ajala, 1999).                                Beside, the insecticides most commonly recommended for use by farmers against insect pests include  plant materials (such as  powders, oils and liquid extracts) which have been tested by experts and proven to be effective in the control of insect pests of stored produce and products as well as field maize in Africa (Mbah, 1990).

Increased demands for clean, safe food supplies on one hand, and the problems associated with expensive chemical control of insects on the other hand have stimulated a search for alternative pest control measures. The financial loss as well as complete loss of propagative seeds especially in the remote areas of the third world due to the attack of insect pests on the world’s cultivated crops, especially maize is unbelievably high. Among the growers of maize however, there has been an increasing consciousness of the vital need of protecting their produce, resulting in a high consumption of insecticides. There has been much progress in the search for biologically active plants and inert materials to replace arsenicals, lead, organic chlorine, silicaflouride insecticides, and so on. Although, the synthetic insecticides are very effective for their particular purposes, yet, they are  environmentally unfriendly. They also possess the serious disadvantages of being toxic to man, domestic and wild-life, non-target insects, useful plants, and enhancing the potential for the development of pesticide resistance (Ofuya  and Lale, 2001; Amadioha, 2004 and Abba, 2005). Synthesized inorganic insecticides exhibit undesirable characteristics that include:

1. Seed viability or germination may be impeded with the use of chemical insecticides due to wrong dosage application and length of time of exposure to chemicals, eg. Fumigants may kill the seed embryo if the seeds are exposed to it for too long.
2. The soaring cost of the conventional insecticides often caused by scarcity and irregular supply.
3. Persistence of chemicals, resulting from their insolubility and eventual adsorption to the soil colloids may be toxic to non-target organisms.
4. Some insecticides such as actellic dust have the undesirable quality of deposition of toxic residues. There is also the risk of drift and environmental pollution.
5. Possession of single active ingredients, which achieve rapid results but have the high risk of the development of resistance by insect pests.

 

Objectives of the Study

1. To identify maize varieties / accessions with some levels of resistance to stalkborer, earworm and grain weevil (Sitophilus zeamais).
2. To determine physical, mechanical and biochemical bases for the susceptibility/resistance of some maize varieties /accessions to stalkborers, earworms and grain weevils.
3. To determine the efficacy of solvent extracts of Erythrophluem africanum Harms  (Ordeal tree ) in the control of zeamais attack on maize grains.

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