FUNGAL PATHOGENS ASSOCIATED WITH FRUIT ROT OF EGG-PLANT (Solanum aethiopicum L.) IN UYO LOCAL GOVERNMENT AREA OF AKWA IBOM STATE

posted on September 2, 2019

CHAPTER ONE

INTRODUCTION

Garden egg (Solanum aethiopicum L.) is a member of the family Solanaceae. The genus Solanum commonly referred to as mock tomato or ‘gilo’ in the Western World comprises of over 1000 species and is almost cosmopolitan with at least 100 indegenus African species. It belongs to the sub-genus Leptostenum, section oliganthes which comprises about 45 species (Dasgupta and Mandall, 1988)

African egg plant, also known as scarlet egg plant is grown throughout Tropical Africa and South America (mainly Brazil) and occasionally consumed fruit vegetable in Tropical Africa in quantity and value, probably the third after tomato and onions and before okra (Lester and Seck, 2004).

According to Dennison and Ahmed (1978) four cultivar groups are recognized within Solanum acthiopicum L. three of which are important for Africa, namely the gilo group which thrives in full sum in woodland savanna on fairly deep and well drained soils, kumba group which grows in hotter conditions with air and humidity some times as low as 20% especially if irrigated, while the shum group thieves under warm, humid conditions and the aculeatum group which is grown in Uganda in swamps during the dry season.

Schippers (2000) reported that none of these cultivar-groups survive cold or very wet conditions. In the humid zone of West Africa, egg plant is mainly grown for its immature fruits (garden egg), in the Savanna area for its leaves and immature fruits and in East Africa, especially Uganda, it is grown mainly as a leaf vegetable. African local egg plant is very popular and play an important role in many diets.

1.1 World Production

African egg plant is one of the most commonly consumed fruit vegetables in Tropical Africa (Agbagwa and Ndukwu, 2004). Reliable statistic for sub-Saharan Africa are not available but a rough estimate for a few countries indicates an annual fruit production of 8000t in Senegal, 60,000t in Cote d’ Ivore and 4500t in Burkina Faso.

Commercial production to supply, cities is increasing as is export to Europe example from Uganda and Senegal (Dennis 1983). According to Jeffries and Koomen (1992), small scale growers account for at least 80% of the total production.

Leaves of Solanum aethiopicum L. are especially important in South Eastern Nigeria, Cameroon and Uganda. Sharma and Kaut (1988) reporte that egg plant is the most popular leafy vegetable by the market in Kampala fruits of bitter Solanum aethiopicum L.called are ‘gilo’ and are important as a market vegetable in Tropical Brazil, where at least 7000ha are cultivated.

Botany And Ecology

Egg plant is a shrub to perennial or annual herb, up to 200cm tall, often much branched. Root system extends both vertically and lateral branches leaves are with or without prickles and stellate hairs (Pathak et. al., 2001).

The leaves are alternate, single stipules absent, petioles up to 1km long, inflorescence lateral racemose cyme up to 5(-2) flowered. Peduncle often short or even absent, filament short and thick, ovary is superior, style-slightly longed than stamen and the stigma is small Eckert (1990) noted that the fruit is a globose to depressed globose, ellipsoid, ovoid or fusiform berry 1-6cm long, smooth to grooved, seedling with epigeal germination, cotyledon thin and leafy.

According to Godara (1994) egg plant does well in a variety of soil textures but prefers rich, well drained soil with pH of 5.5 to 6.8, it thrives in full sun and requires at least five months of warm weather for fruit production. The optimum day growing temperature ranges between 70⁰F and 85⁰F, while it requires temperature ranges of 25 – 35⁰C during the day and 20 – 27⁰C during the night.

Egg plant prefers consistent soil moisture but once established can tolerate dry season. Though water and nutrient absorbing roots reach a depth of 4 feet.

To avoid flower and fruit drop, egg plant are watered deeply and regularly especially during long dry period Eckert (1990). Noda et. al., (1998) noted that harvesting of garden egg should be done preferably in the morning hours to prevent heat.

Proper harvesting is essential or the quantity of the harvested produce cannot be improved but can only be preserved. The perfect egg plant is picked while still immature about 70 – 90 days after sowing, at this point, the skin is glossy and firm, the flesh whitish and the seeds are tender and fully edible (Jefferies and Koomen 1992).

However, fruits for export are sorted in cold rooms, fruits and leaves are not normally processed for long periods, they have a long storage life (up to three months) and transport well. Fresh fruits are taken immediately to the market as it is free of rots and damage (Krostem et al., 1994).

1.3 Nutritional and Medicinal Value

Egg plant is the most popular leafy vegetable of the market mostly throughout Africa. Local garden egg are very popular and play a vital role in many diets (Thind 2001).

The leaves of Solanum aethiopicum L. are used as cooked vegetables in stews and sometimes eaten raw. According to Eckert (1990) egg plant are mostly cultivated as an ornamental plant while some cultivars are occasionally used as root stick for tomatoes. The story and listing of African food would infact be totally incomplete without mentioning the vegetable plant (egg plant) as they represent fertility and blessings.

Moline (1984) reported that it is not uncommon to find them served during ceremonies called Igba or ikan amongst the Yorubas of Nigeria. The leaves of some cultivars provide a reliable and continuing source of income for millions of farmers, as it forms a crucial part of the rural economy. Dasgupta and Mandall (1988) noted that the plants are notable for yielding a lot from a little space, they can produce profit from the tiniest plot, even a few plant grown in garden pots can provide a worthwhile harvest, as it is easy to raise and provides a steady supply of both food and income.

Gupta and Pathak (1990) noted the medicinal application of egg plant which includes the use of roots and fruits as a carminative and sedative used in treatment of colic and high blood pressure, leaf juice is used in treatment of tetanus after abortion while the crushed and macerated fruits are used as enema.

According to Schipper (2000), garden egg is said not to contain huge amount of protein and other nutrients, it is low in sodium and calories and very high in potassium a necessary salt that helps in maintaining the functioning of the heart.

Without exaggeration, garden egg is the perfect recipe for achievement of weight loss within a short period of time, it is also good for diabetic patient as it contains very low calories hence, garden-egg is used as a substitute for meat and fish in soups because of its meaty feelings.

1.4 Objectives of the Study

– To isolate and identify fungi associated with post-harvest diseases of garden egg fruits.

– To determine pathogenicity of the isolated fungi on healthy fruits.

– To evaluate the roles of the isolated fungi in deterioration of nutrient values of garden egg fruits

– To evaluate the effect of common disinfectants on fruits of garden egg.

– To evaluate the efficacy of some fungicides on the fungi.