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Some aspects of the biology of the lemon butterfly Papilio demodocus Esper. (Lepidoptera; Papilionidae) and its preference to three citrus cultivars. By Ali Mukhtar Mohamed Abdallah B.Sc. (Agric.) Honours University of Khartoum, 2000 A thesis submitted to the University of Khartoum in partial fulfillment of the requirements for the degree of M.Sc. Crop Protection Supervisor, Prof. El Sayed El Bashir Mohamed Department of Crop Protection Faculty of Agriculture University of Khartoum December 2006 DEDICATION To my family whose love and pray enlightened my way. To those who gave me care and love, I dedicate this work. ACKNOWLEDGEMENTS Thanks to Almighty Allah who gave me patience to complete this work. It is a pleasure to acknowledge with sincere thanks and appreciation the continuous help and guidance of my supervisor Prof. El Sayed Elbashir for his invaluable help throughout the preparation of the thesis. Thanks are also extended to Dr. Elwasila Guddoura, lecturer at the Department of Crop Protection and to my brother Musab Mukhtar who encouraged me to register for M.Sc. Thanks are due to my friend Elhadi Mursal, for his help and invaluable advice. I would like to thank the staff members of the Crop Protection Department of the Faculty of Agriculture, U. of K. Thanks are due to Sania Jobara, for her help and Fawzia Shukartalla for typing this thesis. LIST OF CONTENTS Title Page Dedication………………………………………….………………………………………………………………………….…… i Acknowledgements …………………………………………………………………………………………………….… ii List of Contents………………………………………………………………………………………………………………... iii List of Tables……………………………………………………………………………………………………………………. vi List of Figures…………………………………………………………………………………………………………………... viii List of Plates…………………………………………………………………………………………………………………....... ix English Abstract …………………………………………………………………………………………………………….. x Arabic Abstract…………………………………………………………………………..……………………………………. xi CHAPTER ONE: INTRODUCTION…………………….…………..……………………………… 1 CHAPTER TWO: LITERATURE REVIEW………………………………………………… 4 2.1. Classification of Papilio demodocus Esper. ..…………………………………… 4 2.2. Morphology .……………………….……………………………………………………………………………….. 5 2..2.1 The Egg………………………………………………………………………………………………………………. 5 2.2.2 The Larva………………………………………………………………………………………………………….... 6 2.2.3 The Pupa…………………………………………………………………………………………………………… 7 2.2.4 Distinguished male and female features……………………………………………. 8 2.2.5 The Adult…………………………………………………………………………………………………………… 8 2.3 Distribution and economic importance……………………………………………… 9 2.4. Life history ..………………………………….…………………………………………………………………….. 12 2.4.1 The egg stage……………………………………………………………………………………………………. 12 2.4.2 The larval stage.………………………..…………………………………………………………………….. 13 2.4.3 The pre-pupal stage..……………………………………………………………………………………… 15 2.4.4 The pupal stage……………………………………………………………………………………………….. 15 2.4.5 Adult life span …………………………………………………………………………………………………. 16 2.5 Host plants ..………………………………..……………………………………………………………………….. 16 2.6 Behavior………………………………………………………………………………………………………………….. 18 2.7 Natural enemies…………………………………………………………………………………………… 20 2.7.1 Natural enemies of the egg………………………………………………………………… 20 2.7.2 Natural enemies of the larva……………………………………………………………... 21 2.7.3 Natural enemies of the pupa………………………………………………………………. 21 2.7.4 Entomopathogenic agents………………………………………………………………………… 22 2.8 Control of Papilio demodocus Esper.……………..………………………………………. 23 2.8.2 Chemical control…………………………………………………………………………………………… 23 2.8.2.1 Insecticides…………………………………………………………………………………………………… 23 2.8.3 Botanicals …………………………………………………………………………………………………………. 24 2.8.4 Mechanical control………………………………………………………………………………………… 24 CHAPTER THREE: MATERIALS AND METHODS……………..………….…… 25 3.1. Site of the study..…………………………………………………………………………...……………………… 25 3.2 Field survey .…………………………………………………………………….…………………………………… 25 3.3 Rearing of Papilio demodocus Esper.……………………………………………………… 26 3.4 Assessment of host preference.……………………………………………………………………… 26 3.6 Morphological studies...……………………………………………………………………………………. 27 CHAPTER FOUR: RESULTS………………………………………………….………………………… 30 4.1 The biology ..…………………………………………….………………………………………………………… 30 4.1.1 Egg stage ..………………………………………………...………………………………………………………… 30 4.1.2 Larval stage ..……………………………...……………………………………………………………………… 30 4.1.3 Pupal stage ..……………………………………….……………………………………………………………… 30 4.1.4 Adult stage ..……………………………………..………………………………………………………………… 33 4.2 The morphology and description……………………………………………………………… 33 4.2.1 The eggs.…………………………………………………………………………………………………………… 33 4.2.2 The larval stage.………………………………………………………………………………………………… 33 4.2.3 The pupa ..…………………………………………………………………………………………………………… 34 4.2.4 The adult……………………………………………………………………………………………………………… 34 4.3 Food preference ……………………………………………………………...……………………………… 38 CHAPTER FIVE: DISCUSSION AND CONCOLUSION…………………… 41 REFERENCES…………………………………………………………………………….………………………………..… 47 APPENDICES 54 LIST OF TABLES Table Title Page The duration of the different immature stages of Papilio 1 demodocus Esper. reared under laboratory conditions 31 (at 20 – 28 ºC and 44 - 63 R.H %.). 2 3 The development period of different stages of Papilio demodocus Esper. The body measurements of the different stages of Papilio demodocus Esper. 32 36 LIST OF FIGURES Fig. Title Page 1 Petri-dishes containing larvae and lemon leaves……………… 28 2 Netted plants………………………………………………………………………………………….. 28 3 Adult rearing cage………………………………………………………………………………... 29 4 Equipment used in the experiment……………………………………………. 29 Damage caused by lemon butterfly fed on host plant for 5 3 days………………………………………………………………………………………………………… 39 Damage caused by lemon butterfly fed on host plant for 6 6 days…………………………………………………………………………………………………………. 39 Damage caused by lemon butterfly fed on host plant for 7 9 days…………………………………………………………………………………………………………. 40 LIST OF PLATES Plate Title Page 1. The different stages in the life cycle of Papilio demodocus Esper. 37 2. The nature of the damage caused by 5th larval instar. 40 ABSTRACT The lemon butterfly Papilio demodocus Esper (Lepidoptera : Papilionidae) also known as, citrus butterfly and orange dog butterfly is a major pest of citrus trees and nurseries in the Sudan. Field surveys were conducted during the course of this study at the nursery and the Shambat Farm of the University of Khartoum while the labrotary experiments were conducted at the Entomology laboratory of the Department of Crop Protection of the Faculty of Agriculture, University of Khartoum. The study aimed to investigate the biology and morphology of the lemon buttterfly reared on leaves of lemon plant, and to determine the degree of preference of the lemon butterfly to different citrus cultivars. The development of the immature stages were followed under laboratory conditions, (20-28°C and R.H. 44-63%). Egg incubation period lasted for 4 to 5 days (average 4.2 ± 0.42). Larval duration lasted for 17 to 19 days with an average of 17.7 ± 0.42 days. Pupal period ranged from 8 to 9 days with an average of 8.2 ± 0.42 days. The whole life cycle lasted for 29 to 32 days averaging 30.2 ± 1.032 days. The egg is small round in shape, pale yellow but turns to dark brown before hatching ; it shows a red mark on the top . The colour of the first three larval instars ranged from black to dark brown and from greenish to bright green for 4th and 5th instars respectively. The adult is quite large in shape, dark brown with numerous pale yellow green spots; the forewings are long and narrow, cream with green longitudinal median wedges. Both sexes are alike but the female is larger than the male in the size . The results showed that, in the nurseries, the larvae of the lemon butterfly preferred lemon to orange and the latter to grapefruit. ﻤﻠﺨﺹ ﺍﻷﻁﺭﻭﺤﺔ ﺘﻌﺘﺒﺭ ﺤﺸﺭﺓ ﺍﺒﻭﺩﻗﻴﻕ ﺍﻟﻤﻭﺍﻟﺢ ﺍﻟﺘﺎﺒﻌﺔ ﻟﺭﺘﺒﺔ ﺤﺭﺸﻔﻴﺔ ﺍﻻﺠﻨﺤﺔ ﻤﻥ ﺍﺨﻁﺭ ﺍﻻﻓﺎﺕ ﻋﻠﻰ ﺍﻟﻤﻭﺍﻟﺢ ﻭﺒﺎﻻﺨﺹ ﻋﻠﻰ ﺍﻟﺸﺘﻭل .ﺸﻤﻠﺕ ﺍﻟﺩﺭﺍﺴﺔ ﺍﻟﻤﺴﺢ ﺍﻟﺤﻘﻠﻲ ﻟﻤﺯﺭﻋﺔ ﺠﺎﻤﻌﺔ ﺍﻟﺨﺭﻁﻭﻡ ﺒﺸﻤﺒﺎﺕ ﻭﺍﻟﺘﺠﺎﺭﺏ ﺍﻟﻤﻌﻤﻠﻴﺔ ﺒﻤﻌﻤل ﺍﻟﺤﺸﺭﺍﺕ ﺍﻟﺘﺎﺒﻊ ﻟﻘﺴﻡ ﻭﻗﺎﻴﺔ ﺍﻟﻤﺤﺎﺼﻴل ﻭﺍﻟﻤﺸﺘل ﺒﻜﻠﻴﺔ ﺍﻟﺯﺭﺍﻋﺔ – ﺠﺎﻤﻌﺔ ﺍﻟﺨﺭﻁﻭﻡ ﺒﻐﺭﺽ ﺩﺭﺍﺴﺔ ﺩﻭﺭﺓ ﺍﻟﺤﻴﺎﺓ ﻭﺍﻟﺸﻜل ﺍﻟﻅﺎﻫﺭﻱ ﻟﺤﺸﺭﺓ ﺍﺒﻭﺩﻗﻴﻕ ﺍﻟﻤﻭﺍﻟﺢ Papilio demodocus Esper.ﻭﺩﺭﺠﺔ ﺘﻔﻀﻴﻠﻬﺎ ﻟﺜﻼﺜﺔ ﺍﻨﻭﺍﻉ ﻤﻥ ﺍﻟﻤﻭﺍﻟﺢ) ﻟﻴﻤﻭﻥ،ﺒﺭﺘﻘﺎل ﻭﻗﺭﻴﺏ ﻓﺭﻭﺕ(. ﺘﻀﻤﻨﺕ ﺍﻟﺩﺭﺍﺴﺔ ﻤﺘﺎﺒﻌﺔ ﻟﺩﻭﺭﺓ ﺤﻴﺎﺓ ﺍﻟﺤﺸﺭﺓ ﺘﺤﺕ ﺍﻟﻅﺭﻭﻑ ﺍﻟﻤﻌﻤﻠﻴﺔ ﺤﻴﻥ ﺘﺭﺍﻭﺤﺕ ﺩﺭﺠﺎﺕ ﺍﻟﺤﺭﺍﺭﺓ ﻤﺎ ﺒﻴﻥ 28-20ﺩﺭﺠﺔ ﻤﺌﻭﻴﺔ ﻭﺍﻟﺭﻁﻭﺒﺔ ﺍﻟﻨﺴﺒﻴﺔ ﻤﺎ ﺒﻴﻥ-44 .%63 ﺨﻼل ﺩﺭﺍﺴﺔ ﺩﻭﺭﺓ ﺤﻴﺎﺓ ﺍﻟﺤﺸﺭﺓ ﻭﺠﺩ ﺃﻥ ﻓﺘﺭﺓ ﺤﻀﺎﻨﺔ ﺍﻟﺒﻴﺽ ﺘﺘﺭﺍﻭﺡ ﻤﺎﺒﻴﻥ 4 ﺇﻟﻰ 5ﺃﻴﺎﻡ ﺒﻤﺘﻭﺴﻁ 4,20± 0,42ﻴﻭﻤﹰﺎ .ﻭﺃﻥ ﻓﺘﺭﺓ ﻨﻤﻭ ﺍﻟﻁﻭﺭ ﺍﻟﻴﺭﻗﻲ ﻻﺒﻭﺩﻗﻴﻕ ﺍﻟﻤﻭﺍﻟﺢ ﺘﺘﺭﺍﻭﺡ ﻤﺎﺒﻴﻥ 17ﺇﻟﻰ 19ﻴﻭﻡ ﺒﻤﺘﻭﺴﻁ 17,7± 0,42ﻴﻭﻤﹰﺎ ﻭﺍﻥ ﻓﺘﺭﺓ ﺘﻁﻭﺭ ﺍﻟﻌﺫﺭﺍﺀ ﺘﺭﺍﻭﺤﺕ ﻤﺎ ﺒﻴﻥ 8ﺇﻟﻰ 9ﺃﻴﺎﻡ ﺒﻤﺘﻭﺴﻁ 8,2 ± 0,42ﻴﻭﻤ ﹰﺎ .ﻭﺩﻭﺭﺓ ﺍﻟﺤﻴﺎﺓ ﺍﻟﻜﺎﻤﻠﺔ ﺘﺭﺍﻭﺤﺕ ﻤﺎ ﺒﻴﻥ 29ﺇﻟﻰ 32ﻴﻭﻤﹰﺎ ﺒﻤﺘﻭﺴﻁ 30,2 ±1,032ﻴﻭﻤ ﹰﺎ. ﻭﻤﻥ ﺨﻼل ﺩﺭﺍﺴﺔ ﺍﻟﺸﻜل ﺍﻟﻅﺎﻫﺭﻱ ﻟﻠﺤﺸﺭﺓ ،ﺃﻭﻀﺤﺕ ﺍﻟﻨﺘﺎﺌﺞ ﺃﻥ ﺍﻟﺒﻴﻀﺔ ﺼﻐﻴﺭﺓ ﻭﻜﺭﻭﻴﺔ ﺍﻟﺸﻜل،ﺼﻔﺭﺍﺀ ﺍﻟﻠﻭﻥ ﺘﺘﺤﻭل ﺍﻟﻰ ﺍﻟﻠﻭﻥ ﺍﻟﺒﻨﻰ ﻗﺒل ﺍﻟﻔﻘﺱ ﻤﻊ ﻭﺠﻭﺩﻋﻼﻤﺔ ﺤﻤﺭﺍﺀ ﻓﻰ ﻗﻤﺘﻬﺎ .ﺃﻤﺎ ﻟﻭﻥ ﻴﺭﻗﺔ ﺍﺒﻭﺩﻗﻴﻕ ﺍﻟﻤﻭﺍﻟﺢ ﻓﻴﺘﺭﺍﻭﺡ ﻤﺎ ﺒﻴﻥ ﺍﻻﺴﻭﺩ ﺇﻟﻰ ﺒﻨﻰ ﻏﺎﻤﻕ ﻤﻊ ﻭﺠﻭﺩ ﺃﺸﻭﺍﻙ ﺒﻁﻨﻴﺔ ﻟﻼﻁﻭﺍﺭ ﺍﻟﺜﻼﺘﺔ ﺍﻻﻭﻟﻰ،ﻭﺍﻟﻠﻭﻥ ﺍﻟﻤﺨﻀﺭ ﺍﻟﻰ ﺍﻻﺨﻀﺭ ﻟﻼﻁﻭﺍﺭ ﺍﻟﺭﺍﺒﻊ ﻭﺍﻟﺨﺎﻤﺱ.ﺍﻟﻌﺫﺭﺍﺀ ﺘﺸﺒﻪ ﺍﻟﺤﺸﺭﺓ ﺍﻟﻜﺎﻤﻠﺔ ،ﺫﺍﺕ ﻟﻭﻥ ﺍﺨﻀﺭ ﺍﻟﻰ ﺒﻨﻰ .ﺍﻟﻁﻭﺭ ﺍﻟﻜﺎﻤل ﻻﺒﻭﺩﻗﻴﻕ ﺍﻟﻤﻭﺍﻟﺢ ﺠﻤﻴل ﺍﻟﺸﻜل ﻭﻜﺒﻴﺭ ﺍﻟﺤﺠﻡ ﻟﻭﻨﻪ ﺒﻨﻰ ﺩﺍﻜﻥ ﻤﻊ ﻭﺠﻭﺩ ﺒﻘﻊ ﺼﻔﺭﺍﺀ ﻤﺨﻀﺭﺓ . ﻫﻨﺎﻙ ﺸﺒﺔ ﻜﺒﻴﺭ ﺒﻴﻥ ﺍﻟﺫﻜﺭ ﻭﺍﻻﻨﺜﻰ ﺇﻻ ﺃﻥ ﺤﺠﻡ ﺍﻟﺫﻜﺭ ﺃﺼﻐﺭ ﻤﻥ ﺤﺠﻡ ﺍﻷﻨﺜﻰ. ﺃﻅﻬﺭﺕ ﻨﺘﺎﺌﺞ ﺍﻟﺘﺠﺎﺭﺏ ﺍﻟﺘﻰ ﺃﺠﺭﻴﺕ ﻓﻰ ﺍﻟﻤﺸﺘل ﺃﻥ ﺍﻟﻴﺭﻗﺎﺕ ﺘﻔﻀل ﺃﻭﺭﺍﻕ ﺍﻟﻠﻴﻤﻭﻥ ﺜﻡ ﺍﻟﺒﺭﺘﻘﺎل ﻭﺃﺨﻴﺭﺍ ﺍﻟﻘﺭﻴﺏ ﻓﺭﻭﺕ. CHAPTER ONE INTRODUCTION The citrus swallowtail butterfly,(orange dog, chequered swallowtail, lemon butterfly) (Papilio demodocus Esper.), belongs to the family Pipilionidae. Its older name was Popilio demoleus Linnaeus (El Khidir, 1968 and Schmutterer, 1969). Papilio demodocus Esper is a major pest of citrus trees and nurseries in the Sudan (Sania, 1992). Papilio demodocus Esper is the common, large black and pale yellow butterfly seen regularly in gardens in South Africa and also occurring in natural vegetation. It occurs in open, often disturbed, habitat throughout Africa south of the sahara, as well as in Cape Verde Islands, Madagascar and Mauritius (Ackery et al., 1995). In the Sudan, Papilio demodocus Esp. is distributed throughout the entire country whenever sufficient citrus trees are found, especially in Equatoria and along river vallies. During the rainy season it is more common than during the dry season (Schmutterer, 1969). Wilson (1950) reported three species of Papilio, other than P. demodocus, which attack citrus trees in northern and central Sudan A powerful flying butterfly, which tends to fly 1-2 m above the ground, like most of the swallowtail butterflies, it usually feeds on flowers while on the wing, similar to hummingbirds. If disturbed before it is ready for flying, such as early in the morning or while it is hardening it's wings after emerging from the pupa, the butterfly will suddenly open the wings fully, exposing the two pairs of eye-like spots on the hind wing. This response is very startling to predatory birds. Some females feed like hummingbirds on the flowers of the native verbine food plants, while busily laying eggs. Citrus (Citrus spp. Rutaceae) cultivars infested by this pest include orange, lemon, lime, mandarin, tangerine, grape fruit, and pomolo. Most of these species of citrus are native to South East Asia. They are thorny, aromatic shrubs or small trees with leathery evergreen leaves. The white or purple flowers are usually very fragrant. They are cultivated from about 45°N to 35°S, between sealevel and l000 m, and are susceptible to frost unless a tree is dormant; they do not grow well in the very humid tropics (Hills, 1981). For many butterflies, an average temperature of 25-26°C, relative humidity of 80-100% and daily rainfall of 50 mm were the most favourable (Mathew, 2001). Peak activity period of P. demoleus L. is synchronized with the emergence of new foliage (Narayanamma and Savithri, 2002). Yunus and Munir (1972) concluded that the caterpillar preferred young nursery plants 1-2 feet high and were capable of completely defoliating nursery groves. In Sudan, the identity of the lemon butterfly infesting the important crop plants (citrus species), the nature and magnitude of the damage it causes were considered by few workers. Generally, the main factors which encourage investigations of the lemon butterfly in Sudan may by summarized as follows: Lack of information about the lemon butterfly, its biology, ecology, behaviour, physiology, efficient methods of control and its natural enemies. Hence, the aim of this investigation focuses on: 1. Study of the biology of Papilio demodocus Esper. 2. Determination of the degree its preference for three main citrus cultivars grown in Sudan: (lemon, orange and grape-fruit). CHAPTER TWO LITERATURE REVIEW 2.1 Classification Kingdom : Animalia Phylum : Arthropoda Class : Insecta Order : Lepidoptera Family : Papilionidae Genus : Papilio Tribe : Papilionini Species : demodocus demodocus Esper (1798) Linnaeus, 1758 (= Papilio demoleus ) Common name : Citrus swallowtail, Christmas butterfly, lemon butterfly, Orange dog. Local Arabic name : ‘Abudagig el Mawalih’ According to Hancock (1983), a new classification of the Papilionidae, based largely on a phylagenetic study of all species, is presented. The 33 genera recognized are placed in 4 sub-families, one fossil and 17 new subgenera. Considerable number of taxonomic changes are proposed, which included splitting of the large genus Papilio into 6 genera and 8 subgenera, this affects a considerable number of well-known and less well-known pest species. A total of 561 species is recognized, of which 4 are fossil. 2.2 Morphology 2.2.1 The Egg The egg is large, pale yellow, nearly spherical about 1.5 mm, basally flattened, smooth. If fertile, a small red mark or cross develops at the egg top. The eggs are laid singly near the edges of the leaves of the food plant. Embryonic development within the egg commences immediately after laying. The egg shell is eaten by the newly emerging larvae, but most of the egg shells or larvae are consumed by various tiny predators that suck out the contents of the egg (Grund, 2002). The egg is spherical but the surface attached to the plant is slightly flattened. It is pale yellow when freshly laid, but the colour changes to brown and, finally to black perior to hatching. The average diameter is slightly less than 1.00 mm (El Khidir, 1968 and Badawi, 1968). Schmutterer (1969) reported that the egg is globular whitish at the beginning and turned to black towards the end of the incubation period. 2.2.2 The larva The young larval stage is brownish to blackish in colour except for the yellowish anterior and posterior parts, and the white central parts. A fully-grown larva is green with black or grey to brownish transverse and longitudinal stripes (Schmutterer, 1969). Grund (2002) reported that the larva passess through five larval instars; initially, black coloured, with two subdorsal rows of short, bristly, fleshy spines. The head is also black. Second, third and fourth instars are dark brown, shiny, with the anterior, middle and posterior parts having broad transverse off-white bands, giving the larva ‘a bird dropping’ camouflage pattern typical for the swallowtail group of butterflies. The fleshy spines are less prominent and not as bristly. They also acquire an additional row of paired fleshy spines on the thorax. Head is brown, smooth, shining, with some short hairs. Fifth instar is 45 mm long, green in colour with a lateral row and two pairs of subdorsal rows of orange or pink spots edged black. The larva eats the egg shell after emergence, before proceeding to scout the leaf surface. Later instars devour the entire leaf, from any part of the plant. 2.2.3 The Pupa The pupa is at first greenish-yellow then it turns brown. There is no silken cocoon round the pupa, this is a naked pupa and typical of that of butterflies. Externally the pupa is rather like the adult having well developed wing pads, thoracic legs and antennae, enclosed in a thin cuticle (Depury, 1968). The pupa is reasonably stout, rugose, about 30 mm long, the ventral part containing the wing cases and the dorsal abdominal parts are bowed, anterior end produced into a short pair of flattened projections, the thorax has prominent projections dorsally and laterally, and there is an additional projection laterally where the abdomen meets the wing case. There are also ridges laterally along the thorax and again between the dorsal and lateral-abdominal projections. It is attached to the thicker stems of the food plant, or to adjacent sticks and rocks. It reclines from the vertical, and is attached by the posterior cremaster and a central silken girdle (Grund, 2002).The colour of the pupal body is determined by a hormone that produces brown coloration, known as the pupal cuticle melanizing hormone (PC MH) which is secreted by the brain suboesophageal ganglion and prothoracic ganglion (Br-SG-PG) complexes during the pharate pupal stage (Yamanaka et al., 1999). Pupa is yellow or brown, fastened in upright position on the tip of the abdomen with a gridle of silk round its thorax (Schmutterer, 1969). 2.2.4 Distinguishing Male and Female Features of The juvenile Stages A search for external morphological characters that would facilitate the sexing of P. demoleus L. in the larval and pupal stages showed that female larvae have pairs of small triangular areas of transparent cuticle on each of the eighth and ninth sternites, and that female pupae have a small narrow verticle furrow extending over these two sternites. Male larvae and pupae can be distinguished only by the absence of these characters (Sarivastara and Kumar, 1979). 2.2.5 The Adult The butterfly has a wing span of 70-86 mm, forewing dark-grey or blackish with numerous sulfur-yellow spots of different sizes. Hind wing has the same ground colour as forewing, with a yellow transverse sub-median band, a number of yellow spots and a colourful eye spot near the anterior and inner margins. Abdomen blackish with longitudinal yellowish stripes (Schmutterer, 1969). A large tailless swallowtail that is mostly creamy yellow and black. Both sexes are alike. In freshly emerged specimens, the cream yellow colour is almost fluorescent, but this lovely brightness gradually changes into rusty orange with age (Poorten, 2004). The butterfly flies by day and females are often seen near the citrus trees on which they lay their eggs, which are round and white and are laid singly on leaves or stems, preferably near young succulent shoots (Depury, 1968). The male and female adults look very much a like (Chua, 1978). The adult is quite large and black with conspicuous bright yellow marking, and has two eye-spots on each hind wing (El Khidir, 1968 and Badawi, 1968). The adult is a handsome swallowtail butterfly often seen feeding on the nectar of various flowers. The general colour is dark brown with numerous pale yellow markings (Hills, 1981). The lemon butterfly is a large butterfly with a wing span about 9 cm (Depury, 1968). 2.3 Distribution and Economic Importance The discovery of this butterfly in the West Indies may be of some importance as this vagile butterfly species is an important citrus pest throughout much of its Old World range, which is rapidly expanding (Badawi, 1981). In India, Narayanamma et al., (2001) reported up to 83% defoliation of young grove trees in Andra Pradesh, and Thakare and Borle (1974) reported an outbreak severe enough to skeletonize an entire citrus garden. Individuals of P. demoleus are seen throughout the year but their populations reach the peak before the onset of the heavy monsoon rains (Poorten, 2004). In Qatar Papilio deomoleus L. was found on cultivated citrus in gardens (Pittaway, 1980). Divender and Gupta (2000) recorded Papilio demoleus (Papilio demodocus) as a serious citrus pest in India where it is distributed country wide. An identical infestation of the citrus dog (Papilio demoleus Linnaeus) increased significantly with the increase in maximum temperature and relative humidity (Chatterjee et al., 2000). P. demoleus larvae accept leaves of at least 19 citrus species or varieties, but show some differences in consumption rates, development time and mortality (Yunus and Munir, 1972). Papilio spp. (P. demodocus Esp: (Africa), P. memon: (South and South East Asia), P. thoat L: (Tropical America) and other species attack the leaves of citrus trees (Schmutterer et al., 1977). The larvae prefer young nursery plants 1-2 feet high and are capable of completely defoliating nursery groves (Yunus and Munir 1972; Thakare and Borle 1974; Singh 1993a; Matsumoto 1996, 2002; Naryayanamma et al., 2001). Papilio demoleus L. occurs in Saudi Arabia, Pakistan, India, South East Asia, South China, Taiwan, Australia, Pupua New Guinea and West Iran (Hills, 1981). Papilio demoleus L., is found throughout Southern Asia (Corbet and Pendlebury, 1992), extending from Iran (Larsen, 1977) to India, and from the Indo-Pacific (Van Wright and de Jong, 2003) to New Guinea and Australia (Parsons, 1998; Braby, 2000), in parallel with the native or introduced range of its principal host plants in the genus citrus (Rutaceae). Papilio demodocus Esp. occurs in many countries in Africa, Asia and Australia where citrus is grown (Schmutterer, 1969). Matsumoto (1996, 2002) reported the recent arrival of P. demoleus into tropical regions such as the Dominican Republic, where favourable climatic conditions and the preferred host plants prevail and where the population of potential natural enemies is low. It could easily spread throughout the West Indies and surrounding areas, including the United States where the impact could be very high. P. demoleus is a successful invasive species, recently spreading throughout an Old World island system very much like that in the Caribbean. Beginning in the 1970s, this species invaded the islands of Java, Borneo, Philippines and Sumarta, apparently facilitated by deforestation and the increased availability of citrus groves. Ram-Pratap et al., (2000) documented the incidence of P. demoleus on lime in Bundel Khan,India from July 1992 to July 1996 and showed that maximum damage by this pest occurs from August to September. In the Sudan, the lemon butterfly is distributed throughout the country, wherever large enough population of citrus trees is found. But it is more common during the rainy season, (July and August) (El Khidir, 1968). The different stages of the caterpillars defoliate the trees and feed at the edges of either flush or hard leaves (Hills, 1981). 2.4 Life History 2.4.1 The Egg Stage The female settles on the host plant and, while still flapping its wings, bends the abdomen downwards on to the leaf surface and lays an egg (Ackery et al., 1995). Two eggs per leaf were noticed on the lower or upper surface of leaves (El Khidir, 1968). Alturi et al., (2002) documented in India larval development through to the adult stage using larvae reared on leaves of lemon (citrus limon Burm) in the laboratory. They noted that eggs are laid singly, but may reach 8-10 eggs over 2-3 days, on the surface of young leaves and twigs. The eggs hatch in 45 days. In the Sudan, the eggs were reported to be laid on the tender leaves and very rarely on the twigs (Badawi, 1968 and Schmutterer, 1969). The eggs are laid singly on flush leaves and hatch after about four days (Hill, 1981). The female readily deposited eggs in response to methanolic extract of the Rutaceous plant Toddalia asiatica (Nakayama et al., 2003). Egg development takes about 6 days under warm conditions (Ackery et al., 1995). The incubation period of the eggs in the Sudan ranged between 3 and 4 days under laboratory conditions (El Khidir, 1968), 4 and 5 days (Badawi, 1968 and Schmutterer, 1969). Farahbaksh and Kashkooli (1978) reported that the female of P. demoleus L. laid 12-77 eggs, and the eggs were laid singly on the lower surface of the young leaves. The egg incubation period averaged 3.61 days, the shortest and longest periods recorded for the egg stage were 3.1 and 6.1 days (Badawi, 1981). 2.4.2 The Larval Stage The larva eats its way out of the egg and then consumes the remains of the egg shell (Ackery et al., 1995). The young caterpillar hatches and feeds on a citrus leaf (Depury, 1968). There are five larval instars; the first three are dark brown with white markings which resemble bird droppings; the fourth and fifth instars are pale green caterpillars with black, brown and grey markings. Fully grown caterpillar is 5 cm or more long. The larval period lasts about 30 days (Hills, 1981). In the Sudan, the average duration of the different instars is: 3.5, 2.9, 4.1, 4.5 and 8.5 days for the first to fifth instars, respectively (El Khidir, 1968). The duration of the fifth instars is 27-35 days (Atluri et al., 2002). In Saudi Arabia, the larval stage took 18-32 days; optimum conditions for rearing of the different stages were 30°C and 21% R.H. (Abu Yaman, 1973). The caterpillar moults several times as it grows and at the last moult it changes colour completely and becomes bright green with some black markings (Depury, 1968). In Pakistan, the duration of 5 larval instars was 3,3,3,3 and 4 days respectively (Rafi et al., 1989). Larvae take about a month to develop, reaching a maximum size of about 45 mm (Ackery et al., 1995). In Djahram area in Iran, the larval stage averaged 16.68 days in AprilSeptemper and 30.85 days in October (Farahbaksh, and Kashkooli, 1978). In Saudi Arabia, the longest and shortest periods recorded for the larval stage were 22.7 and 12.9 days (Badawi, 1981). 2.4.3 The Pre-Pupal Stage Badawi (1968) recorded that the pre- pupal stage took about one, two or three days as exceptional. 2.4.4 The Pupal Stage Alturi et al., (2002) documented that pupation took about 10-12 days. Ackery et al., (1995) reported that when the caterpillar is fully grown, it spins a mat of silk on a twig or leaf of the host plant to which it attaches the tip of its abdomen. It pupates within 2 days, first spinning a griddle of silk to hold itself in a slanting position.The pupal period lasts 2-3 weeks. Schmutterer (1969) mentioned that the pupa is found on twigs. Certain pupae release the butterfly a number of days after pupating (short term pupae), others after some weeks or months (long term pupae). In winter, the life cycle takes about 1- 1.5 months in central Sudan, in summer it is somewhat shorter. In irrigated areas and in Southern Sudan the insect can be found the whole year round. The duration of the pupal period decreased with an increase of temperature , ie averaged 8.0 days during March and 11.87 days during November (Badawi, 1968). 2.4.5 Adult Life Span In Sudan, the adult life span in the field is less than a week (Badawi, 1968). Elsewhere it takes about 7-12 days (Alturi et al., 2002). However, Asokan (1997) recorded an adult longevity of 4-5 days and a total life cycle of 30-50 days. The adult lived for an average of 6.21 days. According to Farahbakhsh and Kashkooli (1978) the life cycle takes an average period of 34.5 days. In Saudi Arabia an adult life span during spring ranged between 4 and 6 days with an average of 5.1 days (Badawi, 1981). The citrus swallowtail passes through about three generations during spring, summer and autumn with the winter period usually spent as a hibernating pupa. One can, however, see the occasional adult during winter (Ackery et al., 1995). 2.5 Host Plant In July 1973, oviposition by Papilio demodocus Esp. on a small plant of Euphorbia pilulifera (Litra) beside a citrus bush was reported in Kenya (Sevastopulo, 1980). Mahesh et al., (2003) reported that lemon was the most preferred and the most suitable food for the development of P. demolues. Deepak et al., (1998) showed that females of P. demoleus preferred babchi (Psoralea corylifolia) more than lemon for egg laying. Larval and pupal periods were longer on babchi than on lemon and larvae took more time to complete their life cycle on babchi than on lemon. Larvae consumed more lemon leaves compared with babchi leaves. The Larval food-hosts are Cullen(Psoralea) spp including C. australasicum (tall verbine), C. cinereum (annual verbine), C. graveolens (native lucerne), C. patens (native verbine), Psoralea pinnata (African scurf-pea) (Leguminosae/ Papilionoideae). Larvae eat the softer green parts of the foodplant. The larvae feed on Citrus spp (Grund 2002). Papilio demodocus has also been found on Aegle marmelos. This note reports its occurrence on Psoralea corylifolia, an important medical herb, in herbal gardens of the regional Horticultural Research station at Jachhin Himachal Pradesh in India (Devender et al., 2000). Yunus and Munir (1972) concluded that the caterpillar preferred young nursery plants 1-2 feet high and were capable of completely defoliating nursery groves. Kroon (1999) reported the following host plants of Papilio demodocus Esper: • Anacordiaceae: Psudospondias sp. • Apiaceae: Archangelica officinalis; Deverra burchelli, Fennel Foeniculum vulgare, Blister bush Peucedanum galbanum, Peucedanum gummiferum, Piturathos burchellii. • Rutaceae: Cape chestnut Calodendron capense, orange and lemon trees Citrus spp., Clausena anisata (= C. inaequalis), Fagara capensis, Oricia bachmannii, O. swynnertoni, Teclea natalensis, Teclea swynnertonii, Toddalia aculeate, Toddalia asiatica, Vepris lanceolata, Zanthoxylum capense, Z. delagoense. • Sapidaceae: Hippobromus pauciflorus (= H. alata). 2.6 Behaviour Observations of the occurrence of dark and light colour patterns in early instar larvae of Papilio spp. in Florida suggested that they may have been selected for disruptive coloration, or mimicry of bird or lizard dropping, depending upon the size of the larval stage and relative occurrence of appropriate models in the species habitat (Minno and Emmel, 1992). The mature larvae which feed on shrubs and small trees of the family Rutaceae, all of which feed and rest in the open on their food plants, are described. These larvae possess distinctive false-face patterns on the caudal end which are exposed to approaching predators moving up a stem or leaf petioles (Minno and Emmel, 1992). When a larva is disturbed by, for instance, a bird, it rears up and uses blood pressure to squeeze out a forked, finger-like orange-coloured organ called an osmetrium from just behind its head. Beside the visual impact of the organ, it also has a strong smell which acts as a further repellent to the predator. The smell is evidently caused by accumulation of substances from the oil glands in the leaves of the host plant. It is thought that it is this osmetrium that gave rise to the term orange for the caterpillar (Ackery et al., 1995). The eversible cervical gland or osmetrium of the larva of P. demodocus Esp., was found to produce a secretion containing isobutyric acid and 2-methyl butyric acid as well as small quantities of methyl and ethyl esters of these acids. The secretion of final-instar larvae differed from that of younger larvae (Burger et al., 1978). The 2nd, 3rd and 4th instars larvae produced qualitatively similar secretions. Remarkable quantitative differences were found between secretions of individual larvae. These variations could not be correlated with the diet on which the larvae were fed, their sex, instar stage or colour form. However, in a number of larvae, the 2 prongs of the osmetrium were found to produce quantitatively different secretions (Burger et al., 1985).Young caterpillars are protected by camouflage, their black, yellow and white colouration making them like bird dropping (Clarke et al., 1963). Saxena et al., (1975) showed that the larvae of P. demoleus L. were attracted more to odours of citral, citronellal and citronellol, but slightly less to geraniol and 1-limonene, and very low to hydroxyl-citronellal and geranyl acetate. These chemicals (except the last) are the main odour constituents of the leaves of the food-plant (citrus). Beck et al., (1999) mentioned the attraction of adult butterflies to moist soil and dirty places (a behaviour termed ‘mud-puddling’). 2.7 Natural Enemies 2.7.1 Natural Enemies of the Eggs Eggs of Papilio demoleus collected from citrus trees in India were found to be parasitized by Telenomus sp., Trichogramma sp. and Ooencyrtus papilionis (a new record from this host in India). A single egg contained 3-7 adult of O. papilionis, which lived for 5 days with a total development period of 11-13 days (Jalali and Singh, 1990). In India Trichogramma shilionis Ishii., and the Scelionid Telenomus sp. parasitize the eggs of Papilio demodocus (Thakare and Borle, 1974). Trichogramma brassicae parasitizes a number of non-target Lepidopteran eggs belonging to different families (Babendreier et al., 2003). Eggs of P. demodocus are parasitized by a small wasp Ooencyrtus spp. (Claasens and Dickson, 1980). 2.7.2 Natural Enemies of Larvae Vespa orientalis and unidentified species of praying mantids are reported as predators of the citrus butterfly Papilio demoleus L. (Singh and Singh, 1998). Distatrix papilionis is a potential braconid larval parasitoid of citrus butterflies causing up to 73% parasitism in India (Mani and Krishnamoorthy, 2000). Thakare and Borle (1974) published photographs of unidentified podisine predators (Hemiptera: Pentatomidae: Asopinae), which along with some unidentified dipteran parasitoids, are suggested to regulate local populations of P. demoleus. Distatrix papilionis (Vireck) Hymenoptera: Braconidae is a potential braconoid larval parasitoid of citrus butterflies causing up to 73% parasitism in India (Mani and Kirshnamoorthy, 2000). 2.7.3 Natural Enemies of Pupae Singh (1993a) reported apparent polymorphism in facultative pupal diapause, and Badawi (1981) reported pupal mortality caused by application of Bacillus infusion. Ackery et al., (1995) recorded pupae parasitized by the wasp Pteromalus puparum (Hymenoptera: Pteromalidae). 2.7.4 Entomopathogenic agents Acytoplasmic polyhedrosis virus was isolated from larvae of Papilio demoleus from citrus orchards in Karnataka, India.Third instar larvae died 9-16 days after inoculation. In some cases the virus was associated with natural parasitism by the braconid Apanteles Papilionis (Narayanan and Gopalakrishnan, 1987). The butterfly Papilio demodocus was controlled with the DD 136 strain of Neoaplectana carpocapsae in laboratory and field trials. At a dose of 600,000 nematodes/tree 63.33% kill of 3rd-instar larvae and 67.67% of 4th and 5th-instar larvae were obtained (Srivastava, 1978). Narayanan and Yayaraj (1975) reported laboratory tests in India the effect of infecting larvae with Bacillus thuringiensis. He used 12 days old infected larvae to measure the mean length, weight and total fat content. When moribund (40-48 hrs after treatment) the values of these parameters were reduced by 47.8, 62.8 and 90.7%, respectively in comparison with healthy larvae. 2.8 Control of Papilio demodocus Esper. 2.8.1 Chemical control 2.8.1.1 Insecticides Srivastava (1978) used the insecticides diazinon, monocrotophos and dichlovovos at concentrations of 0.01 to 0.04% for the control P. demodocus. Singh and Rao (1978) reported that 0.05% methyl-parathion, 0.05% methamidophos and 0.06%. leptophos were the most effective and persistent insecticides for the control of the larvae. Patil and Rajashekhargouda (1985) reported Endosulfan 35 EC at 36ml/18 litres water was effective in controlling the pest. Siddappaji et al., (1977) documented the effectiveness of 14 insecticides sprayed under laboratory conditions against eggs and larvae of Papilio spp. in India. They found that methamidophos and quinalphos were the best and most effective against both stages. The efficiency of 5 insecticides: endosulfan, carbaryl, dichlorvos, HCH and parathion were assessed in field trials against P. demoleus on mandarine, in Jamma, India. All 5 insecticides were effective in reducing infestation, with dichlorvos, carbaryl and parathion being the most effective (Singh and Kumar, 1986). 2.8.2 Botanicals Solunk and Deshpande (1991) reported on the lemon butterfly P. demoleus larvae when fed on citrus leaves dipped in aqueous extract of Ficus religiosa,Parthenium hysterophonus, Azadirachta indica, Caliothropis gigantean or Datura stramonium or untreated control. P. hyterophorus extract caused mean mortality of 52.8% after 72 hrs. Ranjeet et al., (1996) reported on aqueous extract of neem seed kernel at 0.5% which was tested for the control of P. demoleus, a pest of the medicinal tree Aogle mormelos in Karnataka, India. Spraying seedlings twice at an interval of 8 days was effective in providing protection against the pest. Although low mortality (23.3%) was reported, the extract had strong antifeedant and repellent effects and was effective as a moulting inhibitor. 2.8.3 Mechanical Control Manual removal of eggs, larvae and pupae of Papilio demoleus effective in nurseries and young citrus plantations (Doharey and Butani, 1985). Hand-picking of caterpillar can be carried out in nurseries or in individual small citrus trees (Schmutterer, 1969). Hand collection of caterpillar is often effective on small trees (Hills, 1981). CHAPTER THREE MATERIALS AND METHODS 3.1 Site of the Study The experiments were conducted at the Faculty of Agriculture, University of Khartoum, Shambat, during 2005/2006. Shambat is located at the eastern bank of the River Nile (Latitude 51 4 N and longitude 32 32 E.) Surveys were carried out at the university and adjacent farms and laboratory experiments were conducted both at a nursery and in the laboratory of the Department of Crop Protection, Faculty of Agriculture. 3.2 Field Survey Many farms where citrus trees are grown were randomly and periodically surveyed. The purpose of these surveys was to record the infestation of Papilio demodocus Esper., and to collect the different stages(eggs, larvae and pupae) for further studies.. Laboratory studies focussed on the biology of Papilio demodocus Esper and on its preference to three citrus cultivars (lemon, orange and grape fruit), under laboratory and nursery conditions. 3.3 Rearing of Papilio demodocus Esper. Leaves infested with eggs and larvae of Papilio demodocus Esper. were collected from the farm, brought to the laboratory and examined to determine the number and stages of the larvae. Larvae were transferred separately and placed in Petri-dishes (9.0 cm in diameter) (Fig. 1), and supplied with fresh lemon leaves. The leaves were daily renewed and faeces were discarded in order to keep the Petri-dishes clean. The date of pupation and adult emergence were recorded. The newly emerging adults were kept in rearing cages (62.15x45x45 cm), made of wooden frames and covered by wire mesh. A muslin cloth sleeve was attached to one side of the cage to facilitate cleaning, feeding and handling of insects within the cage. Cotton rolls soaked in 10% sugar solution were provided in each cage as food for the adult butterflies. Two fresh twigs of a lemon plant were kept in each cage for oviposition and a branch of Lantana spp. was added to serve as a source of nectar. 3.4 Assessment of host preference Experiments were conducted at Shambat area in an orchard belonging to the Faculty of Agriculture, University of Khartoum during 2005/2006. Preference of Papilio demodocus Esper to three citrus cultivars (orange: Citrus sienensis, lemon: Citrus limon, grapefruit: Citrus paradise) was investigated in a nursery, where four second instar larvae of the lemon butterfly were transferred to each netted plant (Fig 2). Plants free of larvae served as control. Treatments were replicated three times and arranged in a completely randomized block design. The degree of preference was determined by measuring the total leaf area of each citrus cultivar consumed by the larvae. 3.5 Morphological Studies The morphology of the different stages of Papilio demodocus Esper was studied when freshly laid eggs were transferred into small Petri-dishes (5.5 cm in diameter) and kept until they hatched. The external features, the morphometrics and colours of the different stages were recorded. Some adult specimens were also mounted on setting boards whereby different body parts were measured. Fig (1) Petri-dishes containing larvae and fresh lemon leaves Fig (2) Netted Plants Fig (3) Adult rearing cage Fig. (4) Equipment used in the laboratory experiments CHAPTER FOUR RESULTS .4.1 The Biology 4.1.1 Egg stage Females of Papilio demodocus Esper lay eggs at day time singly or in small groups (between 2-3) on the lower and upper surfaces of the citrus leaves. Eggs usually hatch during the day time after an incubation period of 4.20 ±0.42 days (Table 1). The newly emerged larvae eat the egg shells first and then search for other food sources. 4.1.2 Larval stage The larval development period from egg hatching to the pupal stage lasted for 17-19 days with a mean period of 17.8 ±0.79. Table 2 shows the duration of each larval stage. 4.1.3 Pupal stage Table 2 shows the duration of the pupal period, which ranged 8-9 days, (mean 8.2±0.42 days). Before pupation the last larval instar stopped feeding and attached its body to the upper side of the Petridish or to a branch of the food plant by means of a silk mat. Table (1 ) The duration of the different immature stages of Papilio demodocus Esper. reared under laboratory conditions (at 20-28°C and 44-63% R.H). Serial No. of eggs observed Incubation period (days) Larval period (days) Pupal period (days) 1 4 18 8 Total Life cycle (days) 30 2 4 17 9 30 3 5 19 8 32 4 4 18 8 30 5 4 17 8 29 6 4 17 8 29 7 5 17 9 31 8 4 18 8 30 9 4 19 8 31 10 4 18 8 30 Mean 4.2 17.8 8.2 30.2 Sd ± ± 0.42 ± 0.79 ± 0.42 ±1.032 4.1.4 Adult stage Table 2 shows the adult life span, which ranged 4-6 days, (mean 4.5 ± 0.42 days).Adults were always found outside the pupal cases in the morning, indicating that emergence probably occurred during the night or at the early hours of the morning. The total development period from egg to the adult stage ranged from 29 to 32 days (mean 30.2 ± 1.03 days) (Table 1 ). 4.2 The Morphology and Description 4.2.1 The egg The egg of Papilio demodocus Esper is round in shape and less than 1mm in diameter. The newly laid eggs are bright yellow in colour but they become dark brown before hatching and show a red mark on the top (Plate 1“i”). 4.2.2 The larval instar Papilio demodocus Esper. has five larval instars. The first larval instar is black coloured with a white marking, with two subdorsal rows, short bristly, fleshy spines and the head is also black, which resembles a small bird-dropping (plate 1“ii”). The larvae range between 3 mm to 3.5 mm in length, with a mean of 3.15 ± 0.24 mm (Table 3 ). Second instar (plate 1“ii”) and third instar (plate 1“ii”) are dark brown with white markings giving the larva bird dropping camouflage patterns. A Larva ranges between 7.5 mm to 9 mm in length, with a mean of 8.15 ± 0.67 mm,15 mm to18 mm in length, with a mean of 15.6 ± 0.97 mm for second and third instar respectively (Table 3 ). Fourth instar (plate 1“ii”) and fifth instar larvae (plate 1“ii”) are greenish to bright green in colour with some black markings and the mature larvae become bright green in colour. The larvae range between 24 mm to 25 mm in length, with a mean of 24.5 ± 0.53 mm. 45 mm to 50 mm in length, with a mean of 47.5 ± 0.53 mm for fourth and fifth instars respectively (Table 3). 4.2.3 The Pupae The pupa is first greenish-brown and it changes to dark brown later. The pupa is naked and typical of butterfly, and there is no silken cocoon round the pupa. (Plate 1“iii”). The pupal measurements were 23 mm to 25 mm in length, with a mean 23.7± 0.87 mm.(Table 3 ). 4.2.4 The Adult The adult of is a large-sized butterfly, forewings are long and narrow with brown and cream chequers colour with blue eyes and red spots on the hindwings. (Plate 1 “IV”). Wing-span is 80-90 mm, with a mean 85.00±0.47 mm. Total body length from 23 to 25 mm, with a mean 23.8± 0.91 and the antenna was 15.00 mm long (Table 3). There is no tail on the hind wing. Upper fore-wing is largely black and outer wing margin with a series of irregular yellow spots in a discal band. 4.3 Food preference The degree of food preference is measured by the amount of the consumed leaf area under nursary conditions using three citrus species (Orange:Citrus sienensis, Lemon:Citrus limon, Grapefriut:Citrus paradise). The results in (Fig 5) revealed that four larvae per plant during a period of 3 days consumed 118.37,18.99,13.99 cm² of leaf area of lemon, orange and grape fruit respectively. This showed that there was highly significant differences among the citrus species. Lemon was the most preferred host plant. The results in (Fig 6) shows the amount of damage caused by four larvae when kept on the plants for 6 days. The larvae consumed 283.65, 218.16, 125.185 cm² of leaf area of lemon, orange and grape fruit respectively. There were no significant differences between the citrus species with respect to the degree of damage when feeding continued for 6 days. However, the sizes of the leaf area consumed after 9 days were 373,295.26,210.18 cm² of lemon, orange and grape fruit respectively. The degree of prefrence was highly significant among the citrus species and lemon was the most preferred host plant (fig 7). 50 45 40 35 30 25 20 15 10 5 0 R1 R2 G R3 O L Fig. (1). First reading Fig (5) Damage caused by lemon butterfly fed o+n host plant for 3 days 120 100 80 60 40 20 0 R1 R2 G R3 O L Fig. (2). Second reading Fig (6) Damage caused by lemon butterfly fed on host plant for 6 days 140 120 100 80 60 40 20 0 R1 R2 G R3 O L Fig. (3). Third reading Fig (7) Damage caused by lemon butterfly fed on host plant for 9 days Plate ( 2) Nature of damage caused by 5th larval instar CHAPTER FIVE DISCUSSION AND CONCLUSION The lemon butterfly Papilio demodocus Esper. (Lepidoptera: Papilionidae), is one of the major pests of citrus plants, especially in nurseries and on young plants in orchards in Sudan (Sania, 1992). In this study, Papilio demodocus Esper was found to have five larval instars, a result confirming the findings of Elkhider (1968) who reported 5-6 instars. The egg incubation period lasted 4-5 days with a mean period of 4.20 ± 0.42 days. This result also agrees with the findings of Hills (1981), Alturi et al., (1995), Badawi (1981) and Elkhider (1968) who reported an incubation period in Sudan ranging between 3 and 4 days, but it differs from that reported by Rajinder, et al. (1997) who obtained an incubation period ranging from of 2.1 to 3.5 days. The larval period ranged from 17-19 days with a mean duration of 17.8 ± 0.79 days. This is similar to the results of Farahbaksh et al., (1978) and Rafi et al., (1989) who recorded a period of 16 days. On the other hand, El-Khidir (1968) and Hills (1981) reported a larval period of 23-30 days, which is totally different from the findings reported in this study.The prepupal period lasted for one day. This result supports the findings of Rajinder et al., (1997), but it differs from that of Ackery et al., (1995) who reported a pre-pupal period of 2 days. The development period of the pupal stage ranged from 8 to 9 days with a mean period of 8.2 ± 0.42 days. Comparable results were obtained by Badawi (1968) for the shortest pupation period which lasted for 8 days. On the other hand, Badawi reported a period of 22.4 days and Ackery et al., (1995) a period of up to 3 weeks for the longest pupation period. The total duration of the life cycle of the lemon butterfly varies from 29 to 32 days with a mean duration of 30.2 ± 1.032 days. This is generally in agreement with the findings of Rafi et al., (1989) and Schmutterer (1969), but it differs from the results of Mahesh et al., (2002) who reported a period of 30 to 45 days. Adult longevity lasted for a period of 4-6 days which is different from the 7 days reported by Rafi et al., (1989) for both males and females. The egg is round in shape, bright yellow in colour but it turns dark brown before hatching, and it is less than 1mm in diameter. These findings agree with results of Elkhidir (1968) but are different from those of Sania (1992) who reported that the egg of Papilio demodocus was over 1mm in diameter. Rajinder et al., (1997) stated that the average length of the egg was 1.08 mm. These differences may be due to the weather condition and the amount of food taken by the larva. The average body length in the current study of 1st,2nd , 3rd, 4th and 5th larval instar and pupa were 3.15 ± 0.24, 8.15 ± 0.67, 15.6 ± 0.95, 24.5 ± 0.53, 47.5 ± 3.54 and 23.9 ± 0.87 mm, respectively. This result is different from that obtained by Rajinder et al., (1997) who reported the average sizes of the 1st,2nd , 3rd, 4th and 5th instar and pupa as 2.89, 5.60, 7.50, 11.60, 26.5 and 28.86 mm, respectively. The average size of the adult, wing-span and the antenna in the present study were 23.8 , 85.00, and 15 mm, respectively. Other morphological characters of the larval instars, pupae and adult are similar to the findings of Grund (2002), Ackery et al., (1995), Hills (1981), Depury (1968) and Schmutterer (1969). The results show that the lemon butterfly preferred lemon more than orange and that grapefruit was the least attractive cultivar. This result agrees with the findings of Sania (1992) who found lemon more susceptible to attack by the lemon butterfly than orange and grapefruit. Deepak et al., (1998) who reported a comparative study on the biology of Papilio demoleus on lemon Citrus limon and babchi Psoralea corylifolia showed that larvae consumed more lemon leaves compared with babchi leaves, Narayanamma and Savithri (2002) reported that fully grown larvae consumed up to 92.34% of the leaf area of a two-year old sweet orange cv. on the 13th day after release. At four larvae (second instar) per plant 52.5, 72.5 and 80.0% of the leaf area was consumed on the 5th, 10th and 13th day after release on the plant respectively. Saxena et al., (1975), showed that the larvae of P. demoleus L. were attracted more to odours of citral, citronellal and citronellol, but slightly less to geraniol and 1-limonene, and very low to hydroxyl-citronellal and geranyl acetate. These chemicals (except the last) are the main odour constituents of the leaves of the food-plant (citrus). Guenther (1949) reported that lemon leaves have a higher citral content (the attractant to the larvae), while orange and grape fruit leaves have lower content. CONCLUSIONS Infestation of citrus plants with Papilio demodocus Esper (the lemon butterfly) is always synchronized with the flush of new foliage. This insect is an important citrus pest throughout much of the citrus growing areas in the old world. The lemon butterfly is rapidly colonizing new areas which include Saudi Arabia, Pakistan, India, South East Asia, .China, Taiwan, Parts of Australia, Pupua New Guinea and western Iran. In the Sudan Papilio demodocus Esper is found everywhere, especially in Equatoria and along the river Nile valley. The present study was carried out at the laboratory and nursery of the Department of Crop Protection during 2005/2006 in order to study the biology, morphology of lemon butterfly, Papilio demodocus Esper. reared on lemon leaves, and the food preference to three citrus speices (Orange:Citrus sienensis, Lemon:Citrus limon, Grapefriut: Citrus paradise). Labrotary investigations on the biology of the lemon butterfly showed that the egg incubation period was 4.2 ± 0.42 days. There were five larval instars with a mean duration of the larval period of 17.8±0.79 days. The pupal period averaged 8.2 ± 0.42 days, with a total development duration (life cycle) of 29 to 32 days; and a mean duration of 30.2 ± 1.03 days. The morphological studies showed that the egg is small round in shape with red mark on the top. The colour is bright yellow but it become dark brown befor hatching. However, the larval colour ranged from black, dark-brown, greenish and bright green. The pupa has naked shape, typical of butterfly and there is no silken cocoon, the colour is brown. The adult is a large-sized dark brown and cream chequer colour with blue eyes and red spots on hind wings. and there is no tail on the hind wing. Host plant preference tests showed that lemon was the most preferred host followed by orange, and the least preferred host plant was grapefruit. REFERENCES Abu-Yaman, I. K. (1973). Biological studies on the citrus leaf caterpillar, Papilio demodocus Esp. (Lepidoptera: Papilionoidae) in Saudi Arabia. Z. angew. Ent. 72: 376-383. Ackery, P. R.; Smith, C .R. and Van-Wright, R. I. (1995). Carcasson’s African Butterflies.An Annotated Catalogue of the Papilionoidea and Hesperioidea of the Afrotropical Region. CSIRO, Autralia. Alturi, J. B., S.P.V. Ramona, and C.S. Rudi (2002). Life history of Princeps demoleus (Lepidoptera: Rhopalocera: Papilionidae) from India. J. Natl. Taiwan Mus. 55: 27-32 . Asokan, R. (1997). 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APPENDIX Appendix (1) Damage caused by the lemon butterfly fed on different for 3 days host plants R1 R2 R3 Total X Grapefruit 4.87 3.62 5.5 13.99 4.66 Orange 8.81 2.93 7.25 18.99 6.33 Lemon 36.37 35.5 46.5 118.37 39.46 151.35 Total Appendix (2) Damage caused by the lemon butterfly fed on different host plants for 6 days R1 R2 R3 Total X Grapefruit 47.125 42.06 36 125.185 41.72 Orange 68.66 51 98.5 218.16 72.72 Lemon 83.66 85.83 114.16 283.65 94.55 Total 579.87 Appendix (3) Damage caused by the lemon butterfly fed on different host plants for 9 days R1 R2 R3 Total X 56.43 68 85.75 210.18 70.06 Orange 102 2.93 113 295.26 98.42 Lemon 126.08 35.5 124.16 373.9 124.63 Grapefruit Total 879.34 ABBREVIATIONS WHICH APPEARED IN THE TEXT C° degree (s) Celsius centigrade. Cm centimeter (s). Fig. figure (s). g gram. hrs. hours. mm millimeter (s). R.H Relative humidity. U.of K. University of Khartoum.