ABSTRACT

Field experiment was conducted at the Teaching and Research farm of the Department of Crop Science, University of Nigeria Nsukka to compare the activity of Cassia alata leaf extract with two synthetic chemical fungicides applied as seed treatment on the field performance of Nsukka yellow pepper. Four accessions of Nsukka yellow pepper seeds were treated with Apron plus 50 Ds (34% furathiocarb + 10% metalaxyl + 6% carboxine) and Thiram (tetramety1 thioperoxydicarbonic diamide) each at the rate of 30g/100kg of seeds while Cassia alata extracts was used for treatment at the rate of 1ml/100g of seeds. The seedlings were transplanted into the field 42 days after planting. Data were collected on agronomic parameters. Cassia alata compared favourably well with the synthetic chemical fungicide in all the agronomic parameters measured. There were no significant differences between the effects of Cassia alata and the synthetic fungicides on plant height at 50% anthesis, number of branches and number of days to first anthesis. Cassia alata produced better result and differed significantly (p=0.05) with the synthetic chemicals in quantitative character, such as number of leaves at 50% anthesis and number of flowers per plant. The leaf abscission rate was significantly (p=0.05) lower in Cassia alata treated plants (10.1%) compared with Apron plus 50 Ds (10.32%) or Thiram (11.79%). Cassia alata also reduced the number of days to 50% anthesis and number of days to first fruiting (111.7 and 112.7). Evidences in this study show that, Cassia alata extract has potential as seed dressing pesticide for Nsukka yellow pepper seeds.

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INTRODUCTION

Nsukka yellow pepper belongs to the Genus Capsicum in the family Solaneacae. There are about 100 species of Capsicum. They vary in their growth forms, flowering time, fruit shape, size and pungency. Most member of the genus Capsicum originated from wild species except C. anomalum which originated in the new world (Eshbaugh 1980, Macleod et al, 1982). Pepper is propagated by seed and attains a height of 42.0 cm to 72.5 cm, when grown as an annual crop but may attain a height of 130 cm to 160 cm as perennials.

Pepper is valued directly as food for its pungency, colour and aroma and indirectly for its products in pharmaceutical and cosmetics industries. In many communities, the Nsukka yellow pepper is highly cherished for its appetizing aroma. Pepper (Capsicum annum), is an important cash crop but it is affected by many fungal, bacterial and viral diseases. West, (1938) isolated Collectricum capsici, which causes fruit rot from Capsicum annum and Capsicum frutescence. Recently, many fungi organisms have been isolated from certain crop seeds. For example, IIoba (1980) established the

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presence of Trichoderma padwicki and Drechslera oryzae in Nigerian rice seeds. Leveilula taurica (lev) Arn is the main causal agent of powdery mildew on pepper plant (Braun 1980). This fungus Leveillula taurica is present in tropical regions (Hirata 1968). Alegbejo (1996) reported that pepper venial mottle virus (PVMV) is a major limiting factor to pepper production in the wet season in Nigeria.

Pepper is also said to have seed borne, pathogens, which causes seedling blight, root rot, leaf spot, etc. Many synthetic fungicides (Maneb, Zineb, Nabam, Thiram and Mancozeb) are known for their efficacy against seed borne organism (Poachet and Ventura 1963).The problem associated with their use are irritation of the skin, respiratory tract and eyes. Maneb, Thiram and Zineb have been responsible for some case of chronic skin disease in occupationally exposed workers, possibly by sensitization. Hewitt (1998) reported that there was an urgent need to search for an alternative control to synthetic fungicides. This is because of the high residual effect of some pesticides, which have been recognized during the last decade.

Chietwood (1993) reported that higher plants are rich reservoir of interesting compound with biological activity against phytoparasitic pests. According to his report, isolating and identifying these naturally occurring phyto chemicals with biological activity against pest is a logical step in the

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development of new environmentally safe pesticides. The search for a safer pest control product was directed towards the use of agro botanicals.

Singh Up (1997) found that Phenyl Alanine Ammonia Lyase (PAAL) and Trosine Ammonia Lyase (TAL) are the key enzymes in phenol biosynthesis by neem products. These enzymes were earlier found by Schaeider (1994) to be appreciably higher in rice varieties resistant to Xanthomonas oryzae than in the susceptible cultivars. Herger et al (1991) demonstrated that leaf extracts of Regnoutrai sachalinensis the giant knot weed induced resistance in a number of plants against powdery mildews. Daayf et al (1995) in their work treated cucumber leaves with leaf extracts of R. sachalinesis which caused accumulation of phenol that protected the cucumber leaves against Sphaerotheca fuliginea.

Better alternatives are being studied so as to increase quality food and blemish free fruit and vegetables. Among these alternatives is the use of Cassia alata extracts a shrub which grows all year round and flowers during November to January in the forest areas of West Africa. It is used by local people for purgation and for control of skin diseases. Their medicinal properties are due mainly to their content of hydroxyanthracene derivatives. Cassia alata is used in this study as an alternative fungicide. Thus the objectives of this study were: