Biology of castor shoot and capsule borer, Conogethes punctiferalis Guenee (Lepidoptera: Pyralidae)

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1 Biology of castor shoot and capsule borer, Conogethes punctiferalis Guenee (Lepidoptera: Pyralidae) ABSTRACT Ganesha, A. K. Chakravarthy, Mohan I. Naik, K. Basavaraj* and C. Manja Naik Department of Agricultural Entomology, University of Agricultural Sciences, GKVK Campus, Bengaluru , Karnataka, India *E- mail: kadanavar@gmail.com The investigations on the biology of Conogethes punctiferalis Guenee were studied on castor during 2010 Kharif. The results revealed that mean preoviposition, incubation, larval and pupal period lasted for 1.41 ± 0.14, 2.66 ± 0.17, ± 1.92 and ± 0.85 d, respectively. The mean ovipositional period and fecundity was 2.76 ± 0.30 and ± d. Where as, viability of eggs ranged from % with an average of ± 5.09 per cent. Total developmental period of C. punctiferalis occupied ± 0.56 days. Adult longevity ranged from 8.00 to 9.45 and 9.00 to d in case of male and female with a mean of 8.61 ± 0.52 and 9.41 ± 1.97 d, respectively. KEY WORDS: Biology, Conogethes punctiferalis, Ricinus communis INTRODUCTION Castor (Ricinus communis L.) is a non edible oilseed, Euphorbiaceae. India is the world leader in castor production and dominates the international castor oil trade. The Indian variety of castor seed has 48 % oil but only 4 % can be extracted, while the cake retains the rest. The primary cause attributed for lower yields of castor has been due to the damage caused by the insect pests. However, only a few of them such as castor semilooper, castor shoot and capsule borer and leaf miner are considered destructive and appear regularly causing economic losses. Where as others are considered as minor pests. The damage due to shoot and capsule borer was 16 to 72 % in Maharashtra (Bilapate and Talati, 1977). Castor shoot and capsule borer also called as yellow peach moth or cardamom stem borer is distributed in tropical Asia, East Asia and Australia. Larvae of this moth are typically polyphagous pests attacking more than 120 wild and cultivated plants viz., peach, chestnut, durian, citrus, papaya, cardamom, ginger, eggplant and maize (Sekiguchi, 1974). The genus Conogethes is a large, taxonomically complex taxon. Until now ten named species of genus Conogethes have been known from Eastern Palaearctic and Indo-Australian regions. Type locality of C. punctiferalis is India, and so many closely allied species may be included but taxonomic revision of them has been neglected for a long time. There is no consolidated review paper on this pest till now. Though, it is an important pest on 188

2 castor and the work on C. punctiferalis is limited in Karnataka. Considering these facts biology of the pest is essential before formulating the management tactics. Hence, the present study was carried out. MATERIAL AND METHODS internal borer, it is difficult to find cast head capsule. So Dyar s law was used to find out the molting. Number of larval instars was recorded. The grown up larvae were allowed to pupate in the specimen tube (102 mm 25 mm). The total larval and pupal duration were also recorded. Field collected larvae were used for initiating the culture of C. punctiferalis. The larvae were reared on fresh capsules in plastic container (90 cm 30 cm 45 cm). Fresh capsules were provided in every three d interval. After pupation, pupae were transferred to specimen tubes for adult emergence used for further studies. Ten pairs (10 male and 10 female) of freshly emerged adults were released into the insect rearing cage ( cm) for mating and oviposition. The cage was provided with castor inflorescence with capsules held in a vial containing water. Cotton wads soaked in 10 % honey solution served as food for the adults. The plant parts containing the freshly laid eggs were transferred to petridishes for hatching. The emerged larvae were provided with fresh capsules. Rearing was continued till adult emergence. Detailed biology was studied in laboratory on fresh castor capsules. Observations on the incubation period, number of moults, duration of each instar, size, pupal period and total developmental period were recorded. Freshly hatched larvae were transferred with camel hair brush to castor capsules in a plastic box. At each rearing 20 larvae were individually observed, fresh capsules were provided once in 3-4 d. Daily observations were made at six h interval. As C. punctiferalis larva is an For recording longevity and fecundity, ten pairs of moths emerged on the same d were enclosed on castor inflorescence with capsules prepared in a wire mesh cage (0.3 m 3 ). Observations on the mating behavior, oviposition, fecundity and adult longevity were made on moths maintained separately for studies and the observations were continued for five generations. Fresh inflorescences with capsules were provided daily. The eggs laid on different parts of the plants were counted and recorded daily until death of the female moth. RESULTS AND DISCUSSION The freshly laid eggs were pale yellow and oval in outline and firmly glued to the surface. The eggs were deposited singly on capsules and cotton wads were provided for oviposition. The egg length varied from mm with an average of 0.63 ± 0.01 mm and width varied from mm with a mean of 0.46 ± 0.02 mm (Table 1). The egg turned dark yellow on second d, pink eye spots appeared at the anterior end of the egg. Later, an additional brown spot appear between them indicating the developing mandibles prior to hatching, the dark brown coloured head and prothoracic shield of young curled up larva 189

3 were visible through the transparent egg shell. The incubation period in laboratory varied from 2.35 to 3.00 d with an average of 2.66 ± 0.17 days (Table 2). These results are in line with Bilapate and Talati (1978), who recorded the egg size as 0.59 mm and 0.39 mm in length and width, respectively. The incubation period varied from 2.66 ± 0.17 d in close agreement with the observations made by Patel and Gangrade (1971) and Stanley et al. (2009). According to Dyar s law, numbers of larval instars were fixed at five. The head width increased in a regular geometrical progression in successive instars by 1.4 times i.e., first instar 0.15 mm to fifth instar 0.66 mm (Table 4). During its larval period, the caterpillar moulted four times and thus there were five larval instars. The period occupied by each instar was recorded along with their size (Table 1) and period (Table 2). The newly hatched larvae actively moved on the surface of capsules for minutes to find suitable feeding site. The first instar larva was minute, light brown in colour, except for the head and prothorax. The sclerites of the body were dark brown in colour. The larvae were broad at the end and tapered towards the caudal end. Black spots were seen all over the body but they were less visible. The first instar larval length ranged from mm with an average of 1.48 ± 0.08 mm and width ranged from mm with an average of 0.17 ± 0.01 mm (Table 1). As the caterpillar completed its became more or less cylindrical in shape. The first instar larval duration ranged from days with an average of 2.35 ± 0.87 days (Table 2). The second instar larvae were light brown with eye spots and dark mandibles. Within 2-3 h after moult, the colour of the head and prothorax changed to dark brown and body became light brown with brown sclerites. The larval length ranged from mm with an average of 3.38 ± 0.15 mm and width ranged from mm with an average of 0.37 ± 0.01 mm (Table 6). The second instar larval duration ranged from d with an average of 2.30 ± 0.65 d (Table 2). The later three instars of the castor shoot and capsule borer were similar to earlier instars in colour and morphological characters except the size. The larvae of these three instars were light brown with dark brown head, prothoracic shield and sclerites. The spots on the body were deep dark and distinctly visible. The larvae hang on with a fine silken thread when disturbed. The larval length of third instar ranged from mm with an average of 5.55 ± 0.24 mm and width ranged from mm with an average of 0.86 ± 0.02 mm (Table 1). The third instar larval duration ranged from d with an average of 2.10 ± 0.85 days (Table 2). The larval length of fourth instar ranged from mm with an average of ± 0.26 mm and width ranged from mm with an average of 1.59 ± 0.06 mm (Table 1). The fourth instar larval duration first moult, it grew in size and the abdomen 190

4 ranged from d with an average of 2.68 ± 0.92 d (Table 2). The larval length of fifth instar ranged from mm with an average of ± 0.31 mm and width ranged from mm with an average of 2.46 ± 0.09 mm (Table 1). The fifth instar larval duration ranged from days with an average of 2.60 ± 0.59 d (Table 2). In the laboratory total larval period ranged from d with an average of ± 1.92 d (Table 2). The total larval period was reported to be d when it reared on castor (Bilapate and Talati, 1978), d on cardamom in Karnataka (Krishnamurthy et al., 1989), 17 d as reported by Gour and Sriramulu (1992) which were similar to the present observation of ± 1.92 d with range of to d, however, the slight variation in relation to other authors may reveal the effect of host plant and locality of the insect. Kadoi and Kaneda (1990) reported that fully grown larva occupied 32 d on apples and 16 d on fresh maize, while Patel and Gangrade (1971) reported the duration of larval stage varying from d. The colour of the pre-pupa was light greenish with distinct dark brown spots over the body. The Pre-pupal length (Table 1) varied from mm with an average of ± 0.24 mm and width ranged from mm with an average of 2.59 ± 0.11 mm, pre-pupal period lasted for 2.25 to 2.88 d with an average of 2.45 ± 0.21 d (Table 2). The freshly formed pupa Later the pupa turned light brown with dark brown compound eyes. Before emergence pupa turned to dark brown, had seven pairs of spiracles. The first pair was located on mesothorax anterio-laterally and remaining six pairs on third to eighth abdominal segments at lateral sides. Pupal length varied from mm with an average of ± 0.30 mm and width varied from mm with an average of 2.72 ± 0.08 mm (Table 1). Pupal period lasted for d with an average of ± 0.85 d (Table 2). Total developmental period varied from d with an average of ± 0.56 (Table 2) d. This result is comparable with Bilapate and Talati (1978), who reported the pupal duration of 7-9 days. Gour and Sriramulu (1992) reported pupal period of 8 d, while Kang et al. (2004) reported pupal period of 9 to 11 d. Premating period ranged from days with an average of 2.67 ± 0.19 d and pre oviposition period ranged from d with an average of 1.41 ± 0.14 d. Oviposition period ranged from days with an average of 2.76 ± 0.30 d. Fecundity ranged from eggs/female with a mean of ± eggs. Viability ranged from % with an average of ± 5.09 % (Table 3). Total developmental period of C. punctiferalis occupied ± 0.56 d. However it was lower (15-21 d) than that observed by Sloan (1945) on cardamom and on maize (15 d) as recorded by Krishnamurthy et al. (1989). The variations was greenish with brown compound eyes. observed may be due to the change in host 191

5 and weather factors. The developmental period in the present study is more or less in conformity with the reports of Patel and Gangrade (1971) and Krishnamurthy et al. (1989). The adult moths are medium sized brownish yellow with a number of dark spots on wings. Female moths were bigger in size, having bulged abdomen with tuft of hairs. Length of the adult male ranged from mm with an average length of ± 1.22 mm and width ranged from mm with an average of 21.97± 1.81 mm. Length of the adult female ranged from with an average of ± 1.52 and width ranged from mm with an average of ± 1.46 mm (Table 1). Male adult longevity ranged from d with an average of 8.61 ± 0.52 d. Female adult longevity ranged from d with an average of 9.41 ± 1.97 days (Table 3). Bilapate and Talati (1978) reported longevity of female and male moths to be ± 2.50 d and ± 3.80 d, respectively. This variation may be due to changed weather conditions. During the present study fecundity of a female moth ranged from 80 to 110 with an average of ± eggs. Table 1: Morphometrics of life stages of castor shoot and capsule borer (n = 20) Insect stages Length (mm) Width (mm) Range Mean ± SD. Range Mean ± SD. Egg ± ± 0.02 I instar ± ± 0.01 II instar ± ± 0.01 III instar ± ± 0.02 IV instar ± ± 0.06 V instar ± ± 0.09 Pre Pupa ± ± 0.11 Pupa ± ± 0.08 Adult male ± ± 1.81 Adult female ± ±

6 Table 2: Duration of life stages of castor shoot and capsule borer (n = 20) Insect stages Duration (days) Range Mean ± SD. Incubation period I instar II instar III instar IV instar V instar Total larval period Pre pupal period Pupal period ± ± ± ± ± ± ± ± ± 0.85 Total developmental period ± 0.56 Table 3: Adult longevity and fecundity of castor shoot and capsule borer Insect stage Pre mating period (days) Pre oviposition period (days) Oviposition period (days) Fecundity (no. of eggs/female) Viability of eggs (%) Male adult longevity (days) Range Period Mean ± SD ± ± ± ± ± ± 0.52 Female adult longevity (days) ±

7 Table 4: Head capsule width of larvae castor shoot and capsule borer (n = 20) Instar Head capsule width (mm) Range Mean ± SD. Ratio 1 st instar ± nd instar ± rd instar ± th instar ± th instar ± REFERENCES Bilapate, G. G. and Talati, G. M., Studies on the life tables of Dichocrocis punctiferalis Guenee on castor. J. Maharashtra Agril. Univ., 2: Bilapate, G. G. and Talati, G. M., Some studies on bionomics of castor shoot and capsule borer, Dichocrocis punctiferalis (Guenee). J. Maharashtra Agril. Univ., 3: Kadoi, M. and Kaneda, M., Development of yellow peach moth, Conogethes punctiferalis (Guenee) on apple fruit. Res. Bull. Plant Protection Service, Japan, 26: Kang, C. H., Lee, S. M., Chung, Y, J., Choi, K. S. and Park, C. G., Overwintering ecology of the peach pyralid moth, Dichocrosis punctiferalis in Southern regions of Korea. Korean J. Appl. Entomol., 43: Gour, T. B. and Sriramulu, M., Grapevine, Vitis vinifera Linn. a new host of castor shoots and capsule borer, Conogethes punctiferalis (Guenee). Trop. Pest Mgmt., 38:

8 Krishnamurthy, K. K., Khan, M. M., Avadhani, K. K., Venkatesh, J., Siddaramaiah, A. L., Chakravarthy, A. K. and Gurumurthy, B. R., Three decades of cardamom research, Regional Research station, Mudigere ( ). Station Technical Bull., pp Patel, R. K. and Gangrade, G. A., Note on the biology of castor capsule borer, Dichocrocis punctiferalis Gn. (Lepidoptera: Pyralidae). Indian J. Agril. Sci., 41: Sekiguchi, K., Morphology, biology and control of the yellow peach moth, Dichocrocis punctiferalis Guenee (Lepidoptera : Pyraustidae). Bull. Ibaraki-ken Hortic. Experiment Station, 44: Sloan, W. J. S., Insect pests of grain sorghum. Queensland Agric. J., 61: Stanley, J., Chandrasekaran, S. And Preetha, G., Conogethes punctiferalis (Lepidoptera: Pyralidae). Its biology and field parasitization. Indian J. Agric. Sci., 79: Disclaimer: Statements, information, scientific names, spellings, inferences, products, style, etc. mentioned in Current Biotica are attributed to the authors and do in no way imply endorsement/concurrence by Current Biotica. Queries related to articles should be directed to authors and not to editorial board