ABSTRACT
Cucumber (Cucumis sativus L.) belongs to the Cucurbitaceae family. It is a major vegetable crop
worldwide and develops rapidly, with a shorter time from planting to harvest than most crops. It is a
monoecious annual climber or creeper that has been cultivated for over 3,000 years and is still widely
cultivated today. The fruit is soft, succulent with high water content, roughly cylindrical and
elongated with tapered ends. The plant shades one another, being allowed to creep on the ground
thereby having a direct contact with some soil inhabiting disease causing organisms. Its creeping
nature, pre-disposes the plant to pest and disease infestation. However, the production of cucumber
fruits in Nigeria is very low due to some constraints such as incidence of diseases which reduces fruit
yield. Presently, they are produced mainly in the northern states of Nigeria. Studies were conducted
on the production of cucumber in south eastern Nigeria, in order to supplement the high consumption
rate in the region. Planting in April had the lowest disease incidence (3.48%) and severity on leaves
(1.20) and fruits (1.06), followed by September with lower disease incidence (3.60%), disease
severity on leaves (1.22) and fruits (1.17) while July had the highest disease incidence (6.27%) and
disease severity on leaves(1.56) and fruits (1.74). The yields during the April and September
plantings were significantly (p<0.05) higher than other months. April and September had 481.60 and
483.60 tonnes per hectare respectively while July had 19.10 tonnes per hectare. The spray regimes
were significant (p<0.05) on the disease incidence and severity. The plants that received two weekly
spray regime had the lowest disease incidence and severity on leaves and fruits (4.10%, 1.31 and 1.21
respectively) followed by those that received three and four weekly spray regimes. Those that were
not sprayed had the highest disease incidence and severity on leaves and fruits. The plants that were
sprayed fortnightly gave the highest yield of 216.90 tonnes per hectare. The cucumber lines also
showed significant (p<0.05) response to disease incidence and severity with the Supermarketer
having the lowest disease incidence (4.15%) and severity on leaves (1.39) and fruits (1.17) and
Poinsette Holland had the highest disease incidence (5.15%) and Poinsette 76 Holland had the highest
severity both on leaves and fruits (1.45 and 1.35). The supermarketer gave the highest yield of 221.10
tonnes per hectare. The best planting time remains April and September receiving fungicide spray
fortnightly. Supermarketer have also proven to be the best variety to withstand diseases and the
weather condition of a derived savannah agro ecology.
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TABLE OF CONTENTS
Title Page i
Certification ii
Dedication iii
Acknowledgements iv
Table of Contents v
List of Tables vii
List of figures ix
Abstract x
1.0 INTRODUCTION 1
Objectives of the study 2
2.0 LITERATURE REVIEW 3
2.1 Origin 3
2.2 Botany 3
2.3 Plant description 3
2.4 Nutritional and health values of the cucumber fruit 8
2.5 Pests and Diseases 8
3.0 MATERIALS AND METHODS 10
3.1 Description of the study areas 10
3.2 Collection of climatic data 10
3.3 Materials and Methods 10
3.4 Field experiment 10
3.5 Data collection 11
3.6 Laboratory analysis 11
3.13 Data analysis 12
4.0 RESULTS 14
4.1 Laboratory result 14
4.2 Meteorological data 14
vi
4.3 The effect of planting time on phytophtora blight disease incidence and severity . 16
4.4 The effect of spray regimes on phytophtora blight disease incidence and severity . 21
4.5 The response of six cucumber lines on phytophtora blight disease incidence
and severity. 26
4.6 The effect of planting time and variety on phythophtora blight disease incidence
and severity. 31
4.7 The effect of planting time and spray regimes on phythophtora blight disease
incidence and severity. 36
4.8 The cumulative effect of spray regime and variety on phthophtorablight disease
incidence and severity. 41
5.0 DICUSSION 46
5.1 Planting time and disease incidence and severity . 46
5.2 Spray regimes for effective control of phythophtora blight disease incidence.
5.3 The response of the six cucumber line/varieties to phythophtora blight disease
incidence and severity. 47
5.4 The cumulative effect of planting time and variety on phythophtora blight
disease incidence. 48
5.3 The interaction of planting time and spray regimes on the phythophtora blight disease
incidence and severity. 49
5.4 The effect of spray regimes and varieties on phythophtora blight disease
incidence and severity. 49
5.7 SUMMARY AND CONCLUSION 50
REFERENCES 50
CHAPTER ONE
INTRODUCTION
Cucumber (Cucumis sativus L.) belongs to the Cucurbitaceae family. It is a major vegetable
crop worldwide and develops rapidly, with a shorter time from planting to harvest than for
most crops (Wehner and Guner, 2004). The crop is the fourth most important vegetable crop
after tomato, cabbage and onion in Asia (Tatlioglu, 1993); the second most important
vegetable crop after tomato in Western Europe (Phu, 1997) and is the fourth most cultivated
vegetable in the world after tomatoes, brassicas and onions (Wehner, 2007). In tropical
Africa, the crop has not been ranked because of limited use. Cucumber is grown widely in
different parts of the world. It is an all year round out door vegetable in the tropics and an
important greenhouse vegetable especially in Northern Europe and North America (Mingbao,
1991). Phu (1998) stated that cucumber could be cultivated in the field during the summer
and winter in greenhouses using artificial heating. Jizhe (1993) opined that cucumber is a
typical vegetable of warm temperate and cool tropical areas that can be cultivated at any time
of the year. At present; cucumber is cultivated as a field crop in most areas of the world under
frost free conditions. Nu (1998) stated that cucumber is a warm season crop which can be
cultivated at any time but has little or no tolerance to frost and that growth and development
are favoured by temperatures above 20OC. In Nigeria, cucumber can be cultivated at anytime
of the year. During the rainy season, the crop is grown under rain fed conditions and during
the dry season using irrigation facilities; as a result the crop can be seen in most vegetable
markets in Nigeria throughout the year. Many varieties of cucumber exist with varying
shapes, skin colour and carotene content (Simon, 1992) .The variation in the performance of
cucumber varieties has been widely documented by many scholars (Manyvong, 1997;
Ajisefinanni, 2004), which could be as a result of environmental factors or genetic
composition. It is also known for its edible fruits because it is delicious, crispy, high in
nutrients, low in calories and excellent source of fibre needed for a healthy digestive system.
In addition to its palatability and fairly good calorific value, it is reported to be highly
important to human for its medicinal value. It is very useful for natural Diuretic and thus can
serve as active drug for secreting and promoting the flow of urine. Cucumber is a dependable
laxative food for those who suffer constipation. The juice of cucumber is a valuable
medicinal food in the treatment of hyperacidity gastric and duodenal ulcers (Ernestina, 2001).
In Nigeria, Cucumber production and utilization have not been a viable option to farmers
despite the numerous benefits and economic importance of this crop. This might be in part
2
due to the declining soil fertility in conjunction with disease infestation, which prevents
optimum yield and the short shelf life of cucumber fruits which leads to early deterioration.
Cucumbers are susceptible to viral, fungal and bacterial diseases. They are mostly affected by
fungal diseases and this causes significant losses to cucumber crops and currently requires a
high chemical use for their control. Among the fungal diseases is the phytophtora blight
disease caused by Phytophtora capsici (Babadoost , 2005), which is prevalent in the south
eastern Nigerian. It can develop on cucurbit plants at any stage of development; the pathogen
can infect seedlings, vine, leaves and fruits. The infection usually appears first in low area of
the fields where soil remains wet longer. It causes pre- and post- emergence damping-off in
cucumber under wet and warm (20-30 °c) soil condition. Soil-borne diseases have led some
growers to rely upon pesticides treatments. Besides the high annual cost of these treatments,
poor application practices and easy re-introduction of pathogens due to poor hygiene and
sanitation have resulted in frequent disease outbreaks. Furthermore, they are highly toxic
chemicals that pose a significant risk to farm workers and neighbours.
This problem is exacerbated by the fact that there are no chemicals registered for most soilborne
pathogens in cucumbers. Similar problems exist for some foliar diseases (e.g. Botrytis
blights and rots). There has been a rapid development and availability of biological control
products worldwide, yet many of these products have not been objectively evaluated for
efficacy. Similarly, many products have not been validated as part of integrated crop
management systems for Nigerian conditions.
The way the product is applied makes a significant difference to its efficacy.
The objectives of this research therefore are to:
1. Evaluate the effect of planting time on cucumber production.
2. Determine the effect of fungicides spray regime on the control of cucumber diseases.
3. Determine the response of cucumber lines to disease manifestation.
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