ASPECTS OF THE BIOLOGY OF Anomis leona SCHAUS (: NOCTUIDAE), A PEST OF COCOA IN NIGERIA

BY

OLAYIWOLA MAROOF ADEKUNLE PGD (FUTA) CSP/05/7005

A THESIS IN THE DEPARTMENT OF CROP, SOIL AND PEST MANAGEMENT SUBMITTED TO THE SCHOOL OF POST GRADUATE STUDIES IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE AWARD OF MASTERS DEGREE(M.AGRIC.TECH) IN PEST MANAGEMENT (CROP PROTECTION ENTOMOLOGY)

OF THE FEDERAL UNIVERSITY OF TECHNOLOGY, AKURE ONDO STATE, NIGERIA

DECEMBER 2012

ABSTRACT

The fruit piercing , Anomis leona Schaus (Lepidoptera: Noctuidae) is a major defoliator pest of cocoa in Nigeria causing severe losses to farmers in the event of outbreak of the pest. There is scanty information on the pest’s biology in Nigeria prompted this study because of its economic importance in the cocoa economy.Larvae were reared from eggs laid in the laboratory, and some life cycle parameters of Anomis leona were investigated in the laboratory at the Cocoa Research

Institute of Nigeria (CRIN), Ibadan at an ambient temperature of 27±3°C and 70-80% relative humidity In captivity, the relationship of length of life to adult diet was investigated to provide information on which to base a laboratory rearing technique for this pest of cocoa. The adult was fed on 10% commercial sugar solution, a formulation required for it’s gonads maturation.

Measurements of body length and width of different larval stages were taken using a vernier calipers. The detailed morphology of different larval stages of the insect was examined under a binoculars microscope on every moult of the larvae. There were four larval instars and the fourth instar exhibited marked colour polymorphism. Four of such polymorphs were included. The developmental period from egg (2.6days);first instar (7.1days); second instar (2.2days);third instar

(2.5days); forth instar (3.3days); pre-pupal (1.0day) and pupal (7.6days) to adult emergence totalled 26.3 days.There was a significant difference in the adult longevity between virgin males and females reared in the wooden and wicker-framed muslin cages. The total life span of virgin females in the wooden cage varied from 5-9 days with a mean value of 6.8 days while that of males ranged from 4-7 days with a mean value of 5.2 days. The total life span of virgin females reared in the Wicker-framed muslin cloth cage varied from 12-15 days with a mean value of 13.3days while that of males ranged from 15-17days with a mean value of 6.2days. There was no significant difference in the adult longevity of mated males and unmated females: Mated males (10.2 ±

1.07days); mated females (12.6 ± 1.64days); unmated males (16.2± 0.77days); unmated females

(13.3 ± 1.21days).The sex ratio of male to female was 1:1.36.

Chapter One

1.0 Introduction

The cultivated cocoa plant Theobroma cacao Linnaeus 1753 was originally classified into the family Sterculiaceae (Coste, 1992) but has recently been reclassified into the family Malvaceae through the use of molecular markers (Alvenson et al, 1999). Its natural habitat is the lower storey of the evergreen rain forest. There are over twenty species in the but T. cacao is the only one cultivated widely. Since its discovery in the eighteenth century in the Amazon Basin, it’s cultivation has spread to the other tropical areas of south and central America and indeed West

Africa which had become the major producers from the mid 1960s (Opeke,1985).

Cultivation began in Nigeria in about 1874 when a local chief Squiss Ibanigo established a plantation at Bonny in the eastern part of Nigeria. In 1887, the Federal Government from the old

Botanical garden at Ebutte Meta in Lagos sent some seedlings to Ibadan for location trials (Opeke,

1992). Subsequently, cocoa became a dominant tree crop around Ibadan and some other major towns in the southwest Nigeria.

Nigeria recorded her first cocoa export in 1900 (Opeke, 2003). By 1914, Nigeria was producing about 4,000 tonnes per annum and this was less than 2% of the total world production. However, between 1913 and 1930, production increased to about 80,000 tonnes per annum. The importance of coca in the Nigeria economy remained very high which played a significant factor in the economic growth of Nigeria. For instance, in 1969, cocoa export alone earned Nigeria

N106million which represented 40% of all agricultural exports for that year (Sanusi and Oluyole,

2005).

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