Studies on the Biology of Sugarcane Early Shoot Borer, Chilo Infuscatellus Snellen on Artificial Diet in North Coastal Region of Andhra Pradesh, India

International Journal of Social Science & Interdisciplinary Research______ISSN 2277 3630 IJSSIR, Vol. 2 (9), SEPTEMBER (2013) Online available at indianresearchjournals.com

STUDIES ON THE BIOLOGY OF SUGARCANE EARLY SHOOT BORER, CHILO INFUSCATELLUS SNELLEN ON ARTIFICIAL DIET IN NORTH COASTAL REGION OF ANDHRA PRADESH, INDIA

BHAVANI B

SENIOR SCIENTIST (ENTOMOLOGY) REGIONAL AGRICULTURAL RESEARCH STATION, ANAKAPALLE, ANGRAU, ANDHRA PRADESH, INDIA

ABSTRACT: Studies on the biology of sugarcane early shoot borer, Chilo infuscatellus Snellen on bean based artificial diet (in vitro) under laboratory conditions at R.A.R.S., Anakapalle, Andhra Pradesh, India revealed that the ESB moth laid eggs on the ventral surface of the leaf, close to the midrib. The fecundity of female ranged from 368 to 384 and the incubation period ranged from 4.0 to 4.1 days. The larva passed through four moults with five instars and the total larval period ranged from 16.0 to 16.3 days. Pupation occurred in the outermost leaf sheath in a silken cocoon and the pupal period varied from 6.3 to 6.6 days. Longevity of male and female moths varied from 3.5 to 3.6 and 4.0 to 4.2 days, respectively. The sex ratio of male: female was 1:2.28. The total life cycle was completed in 30.2 to 30.7 days. The peak period of activity of the pest was observed from March to May. The present studies clearly indicated that the biology of ESB when reared on bean based artificial diet (in vitro) was not significantly different from the biology on the plant (in vivo) and the artificial diet can be used for rearing ESB under in vitro conditions.

KEY-WORDS: Sugarcane, early shoot borer, Chilo infuscatellus Snellen, biology and artificial diet.

It is a part of Ph.D thesis submitted to the Acharya N.G.Ranga Agricultural University (ANGRAU), Hyderabad, Andhra Pradesh

Sugarcane is a long duration crop with luxuriant vegetative growth and is damaged by a number of insects during its crop growth. Among the insect pests, shoot borer (ESB), Chilo infuscatellus Snellen (Crambidae; Lepidoptera) is a serious pest in peninsular regions of India and more vital in early stages of crop growth causing economic loss (Avasthy and Tiwari,1986). In Andhra Pradesh, ESB starts infestation from germination as shoot borer and continues as internode borer after stalk formation, if not controlled in the early stages of the crop growth under rainfed conditions. It destroys 26 to 65 per cent of mother shoots (Khan and Krishnamurthy Rao 1956) and causes losses from 22 to 33 per cent in cane yield, 12 per cent in sugar recovery and 27 per cent in jaggery (Patil and Hapse,1981). In Andhra Pradesh, due to borer incidence maximum yield loss could go even up to 42% when the incidence was at 60 days age of the crop (Lakshminarayana, 1983). It destroys 58% of shoots in different states, causing reduction of 10.1 to 34.4 tonnes / ha in cane yield and 0.25 to 3.0 units in sugar recovery (Chaudhary, 1973).

International Journal of Social Science & Interdisciplinary Research______ISSN 2277 3630 IJSSIR, Vol. 2 (9), SEPTEMBER (2013) Online available at indianresearchjournals.com

To evaluate sugarcane germplasm against ESB, C. infuscatellus under optimum insect pest populations in field conditions and to study the resistance mechanisms involved under in vitro and in vivo conditions, artificial infestation of ESB larvae is needed to ensure uniform and sufficient level of pest infestation at desired stage of crop growth. Mass rearing of ESB larvae on the natural host (sugarcane shoot) is time consuming due to regular change of plant material and also involves more man power. Not only a lot of plant material is wasted but also frequent handling of the culture results in high mortality of the insects. These drawbacks have led to evolve artificial diet for ESB, C. infuscatellus. Mukunthan and Jayanthi (2001) has made preliminary attempt to develop the bean based artificial diet for the rearing of sugarcane early shoot borer larvae round the year under laboratory conditions at Sugarcane Breeding Institute (SBI), Coimbatore. A preliminary study on the biology of the ESB, C. infuscatellus was made on bean based artificial diet (in vitro) under laboratory conditions at R.A.R.S., Anakapalle, Andhra Pradesh, India and compared with the biology of ESB on plant (in vivo) under net house conditions using the sugarcane variety, 93 A145 to find out the variation in the biology of C. infuscatellus reared under in vitro (artificial diet) and in vivo (on plant) conditions, if any.

Materials and methods

ESB, C. infuscatellus rearing on artificial diet The ESB, C. infuscatellus larvae obtained from field were reared on bean based artificial diet under laboratory conditions (Mukunthan and Jaynathi, 2001) at the Integrated Pest Management (IPM) laboratory, Regional Agricultural Research station (R.A.R.S), Anakapalle. The newly hatched larvae were released on to the bean based artificial diet impregnated with shoot powder of the susceptible check, 93 A 145(Plate 1). For the preparation of shoot powder, shoots of sugarcane ( 93 A 145) were collected from 60 days old plants raised under field conditions and dried in a hot air oven at 800 C for two days and powdered to <80 mesh size. The different ingredients utilised for preparation of the artificial diet were listed in Table 1. All the ingredients of fraction A (Table 1) except the sugarcane shoot powder were blended for 1 minute. Field bean seeds (100 gm) were soaked in water for 24 hours and extruded manually from the seed coat and cooked before use. It was mixed with other ingredients of the medium (Fraction-A) except agar-agar, ascorbic acid, sugarcane shoot powder and ground to a paste. Agar was melted in 80 ml of water (Fraction –B) and sugarcane shoot powder was added to it and poured into the blender containing Fraction-A. All the constituents were blended for three minutes and were autoclaved. Ascorbic acid was dissolved in 30 ml of water and formaldehyde was added to medium just before it began to solidify and poured into a plastic container of 250 gm capacity. After cooling for 2-3 hours in the laboratory, neonate larvae were released on to the artificial diet using a fine brush. The plastic containers were kept in the rearing room in dark for 2 days, as first instar larvae have a strong photopositive behaviour and settle better on the diet in darkness. In the rearing room, temperature was maintained at 28 + 10 C, relative humidity at 60 to 70 per cent and light was provided for 12 hours. The lab culture were supplemented with field collected larvae frequently. The diet was changed for two times at 15 days interval for completion of the total life cycle of early shoot borer. Duration of larval period was recorded in terms of number of days from the release in large cup. The pupae were sexed on the basis of their relative size and genital openings. Duration of pupal

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period was recorded in terms of number of days from pupation till adult emergence. For this purpose, each pupa was kept on a moist blotting paper in petriplate for moth emergence. The males and females were released in net cases in which potted young sugarcane plants were kept. Observations were recorded on oviposition period, fecundity, incubation period, per cent hatch, egg measurements, larval duration, larval length, width and capsule width of 1st to 5th instar larva; pupal duration, per cent pupation; length, width of male and female pupa; length, wing span of male and female adults; adult longevity.

Table 1 List of ingredients of artificial diet used for rearing of C. infuscatellus in the laboratory

S.No. Ingredients Quantity 1 Shoot powder 50.0 g 2 Field bean 100.0 g Fraction- A Casein 50.0 g Yeast 16.0 g Vitamin capsules 8.0 g Salt mixture 5.0 g Ascorbic acid 1.0 g Sorbic acid 0.5 g MPH 1.0 g Fraction –B Agar agar 8.0 g Formalin 1.0 ml Distilled water 470 ml Source: (Mukunthan and Jayanthi 2001)

ESB, C. infuscatellus rearing on plant (in vivo) under net house conditions In order to study the biology of the ESB, C. infuscatellus under in vivo conditions, pot culture of the sugarcane variety, 93 A 145 was maintained in the net house. Sugarcane plants (93 A 145) were grown in medium size plastic pots (Plate ). The potting mixture consisted of red soil and FYM (2:1). Before planting, SSP and MOP were applied @ 100g per pot and one three budded sett planted in each pot. Urea was applied @ 10g per pot after germination. The plants were watered daily as per the need. The newly hatched larvae were released on the 21 days old sugarcane plants using a camel hair brush. After pupation, the pupae were collected and placed on a moist blotting paper in petri dishes for moth emergence. After moth emergence, the males and females were released in pairs in net cages in which potted young sugarcane plants were kept. Observations were recorded on oviposition period, fecundity, incubation period, per cent hatch, egg measurements, larval duration, larval length, width and capsule width of 1st to 5th instar larva; pupal duration, per cent pupation; length, width of male and female pupa; length, wing span of male and female; adult longevity.

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Estimation of oviposition To study the period of maximum egg laying by ESB, C. infuscatellus, egg counts were made once in three days. All the plants in the net house were carefully examined and the number of egg masses / 10 plants at fortnightly interval commencing from January to December were recorded.

Site of oviposition The numerical position of the leaf with the egg mass in a plant was recorded on 50 randomly selected plants. The leaves on the plant were numbered from the youngest visible leaf to the oldest. The number of egg masses found on the leaves was separately recorded with reference to each leaf. Concurrently with this, the location of each egg mass on every leaf was recorded. This was done by dividing a leaf into three parts, namely the bottom one third, the middle one third, and the distal one third.

Number of egg masses laid by adults in captivity Moths that were emerged from bulk rearing of the ESB in the laboratory were separated into males and females. One male and one female moth were introduced in net cage in which potted young sugarcane plants were kept and allowed to mate and lay eggs. The number of egg masses laid by each female after copulation was recorded with dates.

Number of eggs in an egg mass The egg masses collected from potted plants in net house were brought to the laboratory and the number of eggs per single egg mass was counted under a stereoscopic binocular microscope.

Description of different developmental stages To study and describe different developmental stages ( i.e egg, larva, pupa and adult) change in their colour pattern and size etc., were observed daily on artificial diet. To get accurate measurements, various developmental stages were fixed in KAAD (Kerosine oil 1 part, absolute alcohol 10 parts, glacial acetic acid 2 parts and dioxane 1 part). The eggs and larvae of first two instars were measured under microscope with the help of ocular and stage micrometer scale. However, stage of later larval instars, pupae and adults were measured with the help of vernier calipers and scale having accuracy to measure up to 0.5 mm, in each case 10 specimens were measured.

Results and discussion Studies on biology of sugarcane early shoot borer, C. infuscatellus were carried out on bean based artificial diet impregnated with dry shoot powder of sugarcane variety, 93 A 145 under laboratory conditions (in vitro) and compared with biology of ESB on the sugarcane plant (in vivo) under net house conditions during March to May, 2008. Observations were made on oviposition, preferred site for oviposition under field conditions ; morphological features, duration and morphometrics of different life stages of ESB, C. infuscatellus viz., egg, larval instars, pupa, adult, fecundity, sex ratio and fecundity of the pest under in vitro and in vivo conditions and the data were presented in tables from .

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Oviposition/ Fecundity Under field conditions, the oviposition commenced from the middle of January and continued up to the end of August (Table 2). Highest numbers of egg masses were laid during the second fortnight of April (21 egg masses) and the oviposition was reduced after first fortnight of August, thereafter, no oviposition was found except for stray incidence in September and November.

Table 2 Number of egg masses laid by C.infuscatellus in each fortnight under net house conditions Month/Year No. of egg masses 1st fortnight 2nd fortnight Jan, 08 Nil 1

Feb, 08 4 6

Mar, 08 9 19

Apr, 08 18 21

May,08 18 16

Jun, 08 13 11

Jul, 08 9 13

Aug, 08 11 5

Sep, 08 1 Nil

Oct, 08 Nil Nil

Nov, 08 1 Nil

Dec, 08 Nil Nil

However, early shoot borer, C. infuscatellus could be reared in the laboratory throughout the year and oviposition occurred throughout the year and the average number of egg masses laid by a moth was found to be 4.64 under in vivo conditions (Table 3). Under in vitro conditions (on artificial diet), the number of eggs laid per female ranged from 368 to 384, with an average of 376.67 ± 5.85 eggs whereas, under in vivo conditions (plant), the fecundity of female ranged from 328 to 380, with an average of 347.22 ± 14.14 eggs (Table ). The fecundity of the ESB was reported as 429 eggs by Khan and Singh (1942a), 179 eggs by Agarwal and Haque (1955), 400 eggs by Garg and Chaudhary (1979), 338 eggs by Hasabe and Khaire (1994), 262.5 eggs by Venugopal Rao (1998) and 337 eggs per female by Sunil kumar (2003). The variations in fecundity may be ascribed to the fluctuations in the ambient temperature and availability of food. Heavy egg deposition by the ESB moth has observed during April and May, when the average maximum and minimum temperatures ranged from 34.5 0 C to 35.8 0 C and 24.2 0 C to 25.80 C, respectively. The mean relative humidity in the morning during the period varied between 78.5 per cent and 82.87 per cent. The maximum per cent hatching and larval pupation was observed in April followed by May and June as reported by the earlier workers at Anakapalle (Platinum Jubilee Souvenir, 1988).

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Table 3 Number of egg masses laid by C. infuscatellus adults in captivity under net house conditions

Total No. of Number of adults laying female moths Date/Year Two Three Four Five Six masses under One mass observation masses masses masses masses & above

17th Mar, 2008 5 - - - - 3 2

4th Apr, 2008 5 - 3 2

21th Apr, 2008 6 - - - 2 2 2

5th May, 2008 5 - - 2 3

24th May, 2008 6 - - - 1 3 2

4th Jun, 2008 6 - - - 1 3 2

15th Jun, 2008 3 - - - - 2 1

30th Jun, 2008 4 - - - - 2 2

4th Jul, 2008 5 - - 1 2 1 1

23th Jul, 2008 4 - - - 1 2 1

4th Augt, 2008 3 - - - - 2 1

21st Aug, 2008 2 - - 1 1 -

4th Sep, 2008 3 - - - 1 1 1

19th Sep, 2008 2 - - - 1 1 - 3rd Oct, 2008 1 1 - - - - - 20th Oct, 2008 1 1 - - - - - 3rd Nov, 2008 1 1 - - - - - 20th Nov, 2008 2 1 1 - - - - 6th Dec, 2008 2 2 - - - - - 23rd Dec, 2008 1 2 - - - - 20th Jan, 2009 2 1 - - 1 - -

Total 69 7 3 1 11 28 20

Average number of egg masses per adult : 4.64

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Site of preference for oviposition on leaf

Under field conditions, adult female laid eggs in masses, generally on the first three lower green leaves of the plant. Within the leaf, middle portion was more preferred for laying of eggs as evidenced by the data (Table 4). It was very clear that, out of the total 74 egg masses laid by the female moth, 50 egg masses were laid on the middle part of the leaf, 14 egg masses on the lower part of leaf and 10 egg masses on the upper part of the leaf. Maximum percentage of egg laying (67.57%) was recorded on the middle part of the leaf, whereas lowest percentage of egg laying (13. 51%) was observed on the upper part of the leaf. In the middle part of the leaf, it was clear that eggs were always located on ventral surface near the midrib. The preference nearer to the midrib may be attributed to the protection of eggs against mechanical injuries. Generally, the oviposition choice by the ESB female might be for egg survival rather than for a suitable host for the larvae, to enable the dispersal. Choosing smooth, low sites with a crease for oviposition may help protect eggs from desiccation and dislodgement. These findings are in conformity with the findings of Gupta (1940), Usman et al. (1957), Siva Rao and Kamalakar Rao (1963) and Roome et al. (1977 who reported that the eggs were laid nearer to the midrib. Venugopala Rao (1998) reported that the females preferred to lay eggs to an extent of 60.94 per cent in the middle one third portion of the leaf.

Number of eggs in the egg mass

Under field conditions, the number of eggs in an egg mass ranged from 29 to 102, the average being 60.28. Highest number of eggs were observed in an egg mass during the second week (102) and fourth week (100.40) of May whereas lowest number of eggs per mass (29) were observed during the last week of December (Table 5).

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Table 4 Site of ovipositional preference by ESB, C. infuscatellus under net house conditions

Sl. no. Number of egg masses on leaf of the blade Total number of egg Plant masses Lower Middle Upper 1/3rd 1/3rd 1/3rd

1 - 1 - 1 2 1 2 1 4

3 2 2 - 4 4 - 2 1 3 5 2 3 - 5 6 1 2 1 4 7 - 2 - 2 8 2 3 1 6 9 1 3 1 5 10 1 2 - 3 11 - 3 - 3 12 - 4 1 5 13 - 3 - 3 14 - 2 1 3 15 - 3 1 4 16 1 2 1 4 17 2 4 - 6 18 1 3 - 4 19 - 3 - 3

20 - 2 1 3 Total 14 50 10 74 (Grand Total)

18.92% 67.57% 13.51%

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Table 5 Average number of eggs in an egg mass laid by ESB,C. infuscatellus females on 93 A 145 under net house conditions Dates/Year No. of egg masses Total No. of eggs Average number collected of eggs per mass

12th Mar, 08 5 320 64.00

27th Mar, 08 6 412 68.67

12th Apr, 08 6 495 82.50

27th Apr, 08 5 423 84.60

12th May, 08 6 612 102.00

27th May, 08 5 502 100.40

11th Jun, 08 3 268 89.33

26th Jun, 08 4 169 42.25

11th Jul, 08 4 278 69.50

26th Jul, 08 5 347 69.40

10th Aug, 08 3 173 57.67

25th Aug, 08 4 210 52.50

09th Sep, 08 3 137 45.67

24th Sep, 08 2 91 45.50

09th Oct, 08 2 83 41.50

24th Oct, 08 3 129 43.00

08th Nov, 08 2 87 43.50

23th Nov, 08 3 116 38.67

08th Dec, 08 1 36 36.00

23th Dec, 09 1 29 29.00 TOTAL 73 4917 Mean 60.28

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Egg

The eggs of ESB, C. infuscatellus were oval, dorsoventrally flattened, looked like a scale of fish. Eggs were laid in masses in a three to four overlapping rows resembling tiles on a roof and were found to be glued on to the moth during oviposition on the under surface of the leaves. They were creamy white in colour, when freshly laid and gradually changed to yellowish with pin head size spot after 24 hours of egg laying. Empty egg shells were white and remained attached to the leaf. On artificial diet (in vitro), measured on an average 0.89 ± 0.009 mm in length, 0.63 ± 0.007 mm in width whereas, an individual egg measured on an average 0.90 ± 0.02 mm in length, 0.63 ± 0.02 mm in width under in vivo conditions (Table 7).

Incubation period/ Hatchability In the present studies, the egg period ranged from 4 to 4.1 days with an average of 4.06 ± 0.05 days on artificial diet ( in vitro) whereas under in vivo (on plant) conditions, it ranged from 4 to 4.3 days with an average of 4.14 ± 0.11 days (Table 6). These are in close proximity with Karla and Sunil kumar (1966), Habase and Khaire (1994), Venugopala Rao (1998) and Sunil Kumar (2003) who reported the egg period as 4-7 days, 3-6 days, 3.7 days and 4.39 days, respectively whereas Chandy et al. (1964) reported 3 -11 days egg period in Tamil Nadu. Under field conditions, the incubation period was found to be least during the last week of March to second week of April (60-72 hours). It seemed to increase progressively later on. The per cent hatch was more from second week of March to last week of May (93.8 to 99.6%). Incubation period ranged from72.0 to 96.0 hours from May to first week of October whereas, in the winter months (October to December) it was 96-120 hours (Table 6). On artificial diet (in vitro), the per cent egg hatching varied from 65.5 per cent to 90 per cent with an average of 81.83 ± 9.56 per cent while under in vivo ( on plant) conditions it ranged from 69.5 to 94.5 per cent with an average of 87.33 ± 3.35 per cent (Table 7). These results are similar to the findings of Agarwal and Haque (1955), Hasabe and Khaire (1994), Venugopala Rao (1998) and Sunil kumar (2003) who recorded hatching percentage of 88.57 and 83.57, 81.56 and 84.46 ± 3.83, respectively. The variation in egg period and hatchability might be attributed to variation in the atmospheric temperature and relative humidity in that location.

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Table 6 Per cent hatch and incubation period of eggs of C. infuscatellus on susceptible check (93 A 145) net house condtions

Egg masses No of Total No. of eggs hatched per mass Percent collected on eggs/mass hatch 72-84 60-71 85-96 97-120 hours hours hours hours 12th Mar, 08 64 - 7 53 - 93.8

27th Mar, 08 68.67 - 14 53 - 97.6

12th Apr, 08 82.5 - 17 62 - 95.8

27th Apr, 08 84.6 - 12 69 - 95.7

12th May, 08 102 - 11 89 - 98.0

27th May, 08 100.4 - 12 88 - 99.6

11th Jun, 08 89.33 - 3 69 - 80.6

26th Jun, 08 71.25 - 21 32 - 74.4

11th Jul, 08 69.5 - 11 41 - 74.8

26th Jul, 08 69.4 - - 47 - 67.7

10th Aug, 08 57.67 - - 39 - 67.6

25th Aug, 08 52.5 - - 35 - 66.7

09th Sep, 08 45.67 - - 28 - 61.3

24th Sep, 08 45.5 - - 23 - 50.5

09th Oct, 08 66.5 - - 24 - 84.2

24th Oct, 08 73 - - - 35 83.6

08th Nov, 08 43.5 - - - 32 66.7

23th Nov, 08 38.67 - - - 23 54.3

08th Dec, 08 36 - - - 25 52.8

23th Dec, 09 29 - - - 18 44.8

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Heavy egg deposition by the ESB moth has observed during April and May, when the average maximum and minimum temperatures ranged from 34.5 0 C to 35.8 0 C and 24.2 0 C to 25.80 C, respectively. The mean relative humidity in the morning during the period varied between 78.5 per cent and 82.87 per cent. The maximum per cent hatching and larval pupation was observed in April followed by May and June as reported by the earlier workers at Anakapalle (Platinum Jubilee Souvenir, 1988).

Larva

First instar larva was active, grayish white in colour with black head and immediately after hatching moved fast in search of the food material. Under in vitro (on artificial diet) conditions, it measured on an average 1.85 ± 0.03 mm in length, 0.2 ± 0.01 mm in width of the body and the head capsule was 0.23± 0.01 mm in width whereas, the length and width of the body and width of the head capsules was 1.84 ± 0.03mm, 0.21 ± 0.01mm and 0.24 ± 0.01mm on an average, respectively under in vivo (on plant) conditions (Table 7).

The second instar larva was dirty white in colour with prominent dark stripe on mid dorsal portion and impressions of the stripes were found on the body. Under in vitro conditions, the length of the second instar larva was on an average 5.26 ± 0.052 mm, 0.49 ± 0.008 mm in width and the head capsule was 0.4 ± 0.004 mm. Under in vivo conditions, it measured on an average 5.23 ± 0.13 mm in length, 0. 48 ± 0.01 mm in width of the body and the head capsule was 0.38± 0.02 mm in width (Table 7).

The third instar larva was dirty white in colour with dark black head. Black spots on tubercles were absent. Under in vitro conditions, the average length, width of the body and width of the head capsule were 12 ± 0.005 mm, 1.98 ± 0.003 mm and 1.33 ± 0.007 mm whereas average length, width of the body and width of the head capsule were 11.95 ± 0.09 mm, 1.95 ± 0.02 mm and 1.30 ± 0.02 mm, respectively under in vivo conditions. (Table 7).

The fourth and fifth instar larva was also dirty white in colour with dark brown head. The body possesses five violet stripes, one on dorsal surface, one pair each on the sub-dorsal and lateral surfaces of the body (Plate 2). Black spots were observed on the tubercles which were present on the eight abdominal segments. Under in vitro conditions, it measured on an average 17.1 ± 0.01 mm in length, 2.88 ± 0.009 mm in width of the body and the head capsule was 1.8 ± 0.007 mm in width. Under in vivo conditions, the body measured on an average 17.07 ± 0.03 mm length, 2.83 ± 0.07 mm width, whereas the width of head capsule was 1.8 ± 0.02 mm (Table 7 ).

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Table 7 Morphometrics of the life stages of the ESB, C. infuscatellus in vivo (plants) and in vitro (artificial diet) conditions S. in vivo in vitro Stage of the insect No. Mean(mm)* range (mm) ± SD Mean (mm)* range (mm) ± SD 1 Egg a. Length 0.89 0.88-0.9 0.02 0.90 0.87- 0.94 0.02 b. Width 0.63 0.62-0.64 0.02 0.63 0.6 - 0.65 0.02 2 I instar larva a. Length 1.85 1.84- 1.86 0.03 1.84 1.8 - 1.88 0.03 b. Width 0.20 0.2-0.22 0.01 0.21 0.19 - 0.24 0.01 c. Width of the Head capsule 0.23 0.23-0.24 0.01 0.24 0.23 - 0.26 0.01 3 II instar larva a. Length 5.26 5.2- 5.3 0.05 5.23 5 - 5.4 0.13 b. Width 0.49 0.48-0.5 0.01 0.48 0.46 - 0.5 0.01 c. Width of the Head capsule 0.4 0.39-0.4 0.01 0.38 0.35 - 0.41 0.02 4 III instar larva a. Length 12 11.99-12 0.01 11.95 11.96 – 12 0.09 b. Width 1.98 1.97-1.98 0.01 1.95 1.92 - 1.98 0.02 c. Width of the Head capsule 1.33 1.31-1.33 0.01 1.30 1.27 - 1.34 0.02 5 IV instar larva a. Length 17.1 17.08-17.11 0.01 17.07 17.04- 17.11 0.03 b. Width 2.88 2.86-2.89 0.01 2.83 2.8 - 2.9 0.07 c. Width of the Head capsule 1.80 1.78-1.82 0.01 1.80 1.74 - 1.82 0.02 6 V instar larva a. Length 23.88 23.8-23.9 0.04 23.92 23.85 – 24 0.07 b. Width 3.49 3.48-3.5 0.01 3.49 3.47 - 3.5 0.01 c. Width of the Head capsule 1.92 1.88-1.94 0.02 1.89 1.85 - 1.94 0.03 7 Pupa(Male) a. Length 12.49 12.48-12.5 0.01 12.49 12.47 - 12.5 0.01 b. Width 2.22 2.2-2.23 0.01 2.23 2.21 - 2.23 0.01 Pupa(female) a. Length 17.2 17.19-17.2 0.01 17.19 17.18 -17.21 0.01 b. Width 3.26 3.24-3.26 0.01 3.26 3.2 - 3.29 0.03 8 Adult(Male) a. Body length 9.92 9.9-9.92 0.01 9.92 9.9 - 9.95 0.02 b. Wing span 22.05 21.99-22.1 0.05 22.01 21.96 - 22.1 0.05 Adult(Female) a. Body length 13.46 13.4-13.5 0.05 13.46 13.4 - 13.5 0.05 b. wing span 25.42 25.4-25.43 0.01 25.41 25.36 - 25.43 0.02 *Mean of 10 individuals SD: Standard Deviation

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Under in vitro conditions, the average length of the fifth instar larva was 23.88 ± 0.04 mm, 3.49 ± 0.008 mm in width of the body and the head capsule was 1.92 ± 0.02 mm in width whereas under in vivo conditions, the average measurement of fifth instar larva was 23.92 ± 0.07 mm length, 3.49 ± 0.01 mm width and 1.89 ± 0.03 mm width of head capsule (Table 7). The earlier biology studies on ESB indicated that the full grown larvae measured about 20-25 mm in length (Ramakrishna Ayyar and Margbandlu, 1935, Gupta, 1940), whereas in the present study it was 23.88 to 23.91 mm in length and 3.49 to3.54 mm in width. These findings are in agreement with the earlier findings in respect to the size of mature larvae (Gupta, 1940, Venugopal Rao, 1998 and Sunil Kumar, 2003). The findings on the duration of five larval instars in the present study are in conformity with reports of Chandy et al.( 1964), Venugopala Rao (1998) and Sunil Kumar (2003). The young larvae immediately after hatching crawled to the tip of the leaf and suspended themselves by a silken thread and has reached the base of the shoot. It has also observed that the newly hatched larvae were observed first feeding on the leaf sheaths as a miner and only after attaining second instar stage, started boring into the shoot. The larva has been observed to feed on the growing point and consequently unopened spindle leaves were found to be damaged at the base and finally the ‘deadheart’ formation occurred in about 10 days after the entry of borer into the plant. Similar behaviour of larvae was observed by Khan and Singh (1942b), Gupta (1957), Usman et al. (1957), Siva Rao (1960), Karla and Sunil Kumar (1966) and Venugopala Rao (1998) Larval period

On artificial diet (in vitro), the total larval period ranged from 16 to 16.3 days with an average of 16.1 ± 0.11 days. The duration of first instar larva ranged from 2.1 to 2.2 days with an average of 2.14 ± 0.05 days. The duration of second instar larva was 3 to 3.10 days with an average of 3.04 ± 0.05 days. The duration of third instar larva ranged from 3 to 3.2 days with an average of 3.16 ± 0.05 days and that of fourth instar larva ranged from 3.2 to 3.3 days with an average of 3.21 ± 0.03 days. The fifth instar larva took about 4.5 to 4.6 days, with an average of 4.54 ± 0.05 days to enter into pupation (Table 8). On plant (in vivo), the larval period ranged from 16.4 to 17.2 days with an average of 17.03 ± 0.23 days. The duration of first instar larva was ranging from 2.1 to 2.3 days with an average of 2.19 ± 0.09 days. The duration of second instar larva was 3.1 to 3.4 days with an average of 3.21 ± 0.09 days. The duration of third instar larva ranged from 3.2 to 3.5 days with an average of 3.31 ± 0.11 days and that of fourth instar larva ranged from 3.5 to 3.7 days with an average of 3.6 ± 0.07 days. The fifth instar larva took about 4.7 to 4.9 days, with an average of 4.72 ± 0.11 days to enter into pupation (Table 8). The response on artificial diet could be exploited for quicker screening of sugarcane cultivars against the borer pest. These results are in close conformity with those of Khan and Singh (1942a), Chandy et al. (1964), Venugopala Rao (1998) and Sunil Kumar (2003).

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Pupa Pupa was ‘obtect’ type. The newly formed pupae were grayish in colour. The integument transparent, turned light brown in colour on the second day and subsequently turned to dark brown. The female genital aperture is situated on the eighth abdominal segment in the form of a slit while the male genital aperture was situated on raised oval sclerite with linear depression in the middle of ninth abdominal segment. Under in vitro conditions, male pupa measured on an average 17.2 ± 0.005 mm in length and 3.26 ± 0.008 mm in width. Under in vivo conditions, the average size of the male pupa was 12.49 ± 0.01 mm in length and 2.23 ± 0.01mm in width. The female pupa was slightly bigger in size and was 17.19 ± 0.01 mm in length and 3.26±0.03 mm in width (Table 7 and Plate 4). These findings are comparable with the findings of Gupta (1940 and 1959), Venugopala Rao (1998) and Sunil Kumar (2003) who reported the approximate length of male pupa as 13 mm and that of female as 17 mm. Pupal period On artificial diet (in vitro), the pupal period ranged from 6.3 to 6.6 days with an average of 6.43 ± 0.13 days whereas it ranged from 6.8 to 7 days, with an average of 6.91 ± 0.08 under in vivo (on plant) conditions (Table 8). These results are comparable with the observations of earlier workers with reference to C. infuscatellus in different states of India. The pupal period varied from 7-13 days at Lyallapur (Khan and Singh,1942), 8-10 days in Uttar Pradesh (Gupta, 1953), 12-24 days in Bihar (Agarwal and Haque,1955), 7-8 days (Usman et al.,1957), 7-13 days in Tamil Nadu (Chandy et al., 1964), 5-8 days in Rajasthan (Karla and Sunil Kumar, 1966), 8-10 days in Haryana (Garg and Chaudhary,1979), 7 days (Patil and Hapase,1981) and 5-9 days in Maharastra (Hasabe and Khaire,1994), 7.7- 19.2 days in Assam (Saikia et al., 1996) and 6 – 10 days with an average of 7.2 days in Andhra Pradesh (Venugopala Rao,1998). The larvae pupate within the shoot itself generally at its base. Before pupating, a larva cuts a slanting hole leading outside the shoot and plugs it with its fros to facilitate emergence of the adult moth later.

Adult The female adult moth was light straw to brownish in colour without any dark markings on the outer edge of the forewings and the hind wings were grayish white in colour (Plate ). The male moths were light straw to brownish grey coloured forewings with dark markings on the outer edge and grayish white hind wings (Plate 4). Female moths were observed to be slightly bigger in size than male moths. Under in vitro conditions, male adult measured an average body length of 9.92 ± 0.009 mm with wing expansion of 22.01 ± 0.05 mm whereas female adult measured 13.46± 0.05 mm body length and 25.41 ± 0.009 mm wing expansion. Under in vivo conditions, the body length of the male moth was 9.92 ± 0.02 mm, while the female was 13.46 ± 0.05 mm on average. The average wing expanse in males was 22.01 ± 0.05 mm while that of female was 25.41 ± 0.02 mm (Table 7). These measurements are almost similar to those recorded by Isaac and Misra (1933), Gupta (1940, 1959), Venugopala Rao (1998) and Sunil Kumar (2003) who reported that the size of moth after wing expanse varied from 19-26 mm in male and 25-33 mm in female.

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Adult longevity

The longevity of adult male moths, which were reared on artificial diet (in vitro) ranged from 3.5 to 3.6 days with an average of 3.57 ± 0.05 days, while that of the females ranged from 4 to 4.2 days with an average of 4.13 ± 0.1 days. Under in vivo conditions, the longevity of male and female moths ranged from 3.6 to 4 days with an average of 3.73 ± 0.13 days and 4.3 to 5 days with an average of 4.57 ± 0.33 days, respectively (Table 8) which are in close conformity with the findings of Habase and Khaire (1994), Venugopala Rao (1998) and Sunil kumar (2003).. Higher percentage of viable eggs (376.67 ± 5.85) per female were obtained from the moths reared on artificial diet compared to those obtained from the moths reared on sugarcane plant (347.22 ± 14.14).

Total life cycle

The data collected on life history indicated that the ESB, C. infuscatellus on artificial diet (in vitro) completed its life cycle with in a period of 30.2 to 30.7 days with an average of 30.44 ± 0.22 days whereas on plant (in vivo) it ranged from 31.15 to 32.55 days with an average of 32.22 ± 0.28 days (Table 8) and the results were more or less in agreement with reports of Gupta (1940), Khan and Singh (1942a), Siva Rao and Kamalakara Rao (1963), Chandy et al.(1964), Garg and Chaudhary (1979), Habase and Khaire (1994), Venugopala Rao (1998) and Sunil kumar (2003).

Sex ratio

From the data in table 9, it was evident that more female moths emerged compared to male moths and the ratio of males to females was 1:2.28 under in vitro conditions ( on artificial diet) whereas, it was 1:2.08 under in vivo (on plant) conditions (Table 9 ). This is in agreement with Usman et al. (1957 ), Venugopal Rao (1998) and Sunil kumar (2003) who reported the male to female sex ratio as 1:2.0, 1:1.98 and 1:1.92, respectively.

The present studies on biology of ESB have clearly indicated that the biology of ESB reared on bean based artificial diet (in vitro) was not significantly different from the biology of the ESB reared on plant (in vivo). Hence, the bean based artificial diet could be used for the mass rearing of ESB, C. infuscatellus under laboratory conditions.

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Table 8 Duration of different developmental stages of ESB, C. infuscatellus in vivo and in vitro conditions

S. No Stage of the insect in vitro in vivo Mean* range (days) ± SD Mean* range (days) ± SD 1 Incubation period 4.06 4 - 4.1 0.05 4.14 4-4.3 0.11

2 Larval period

A I instar 2.14 2.1 - 2.2 0.05 2.19 2.1 - 2.3 0.09

B II instar 3.04 3.0 - 3.1 0.05 3.21 3.1 - 3.4 0.09

C III instar 3.16 3.0 - 3.2 0.05 3.31 3.2 - 3.5 0.11

D IV instar 3.21 3.2 - 3.3 0.03 3.60 3.5 - 3.7 0.07

E V instar 4.54 4.5 - 4.6 0.05 4.72 4.7 - 4.9 0.11

Total larval period 16.10 16 - 16.3 0.11 17.03 16.4 -17.2 0.23

3 Pupal period 6.43 6.3 - 6.6 0.13 6.91 6.8 – 7 0.08

4 Adult longevity

A Male 3.57 3.5 - 3.6 0.05 3.73 3.6 – 4 0.13

b. Female 4.13 4 - 4.2 0.10 4.57 4.3 – 5 0.33

Average 3.86 3.75 - 4.2 0.05 4.14 3.95 - 4.4 0.17

5 Total life cycle 30.44 30.2 -30.7 0.22 32.22 31.15 - 32.55 0.28

6 Fecundity (No.) 376.67 368 -384 5.85 347.22 328 – 380 14.14

7 Per cent hatching(%) 81.83 65.5 - 90 9.56 87.33 69.5 - 94.5 3.35 * Mean of 10 individuals SD: Standard deviation

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Table 9 Sex ratio of ESB, C. infuscatellus reared under in vitro and in vivo conditions

in vitro in vivo S. No Number Male Female Sex ratio S. No Number Male Female Sex ratio of pupae of pupae observed observed 1 14 4 10 1 : 2.50 1 12 4 9 1 : 2.25

2 17 5 12 1 : 2.40 2 10 4 6 1 : 1.50

3 10 3 7 1 : 2.33 3 14 4 10 1 : 2.50

4 13 4 9 1 : 2.25 4 10 4 7 1 : 1.75

5 15 5 10 1 : 2.00 5 13 5 8 1 : 1.60

6 10 3 7 1 : 2.33 6 10 3 7 1 : 2.33

7 12 4 8 1 : 2.00 7 8 2 6 1 : 3.00

8 10 3 7 1 : 2.33 8 12 4 9 1 : 2.25

9 13 4 9 1 : 2.25 9 10 3 7 1 : 2.33

10 14 4 10 1 : 2.50 10 12 4 8 1 : 2.00

Total 128 39 89 1 : 2.28 Total 111 37 77 1 : 2.08

International Journal of Social Science & Interdisciplinary Research______ISSN 2277 3630 IJSSIR, Vol. 2 (9), SEPTEMBER (2013) Online available at indianresearchjournals.com

Acknowledgements

The authors are thankful to the Director of Research, ANGRAU, Associate Director of Research, RARS, Anakapalle and Professor & Head, College of Agriculture, Rajendranagar for providing facilities during the research work.

References cited Agarwal S B D and Haque 1955 Studies on Argyria sticticraspis Hampson the early shoot borer. Indian Journal of Entomology 17: 307-314. Avasthy P N and Tiwari N K 1986 The shoot borer Chilo infuscatellus Snellen. In : Sugarcane Entomology in India (eds: David H S Eswaramoorthy and R Jayanthi) Sugarcane Breeding Institute, Coimbatore pp. 69-92. Chandy K E, Venkatraman T and Kareem A 1964 Studies on Chilotraea infuscatellus Snellen the early shoot borer in Madras state. Proceedings of All India Conference of Sugarcane Research and Developmental Workers 5: 524-528.Chaudhary, 1973 Garg D O and Chaudhary J P 1979 Insect pests of sugarcane in Punjab and their control II. Borers. Indian Sugar 28 : 749 -775. Gupta B D 1940 The anatomy, life and seasonal histories of striped moth borers of sugarcane in north Bihar and West U.P. Indian Journal of Agricultural Sciences 10: 787-817. Gupta B D 1957 Shoot borer Chilotraea infuscatellus Snellen attack in relation to tillering in sugarcane. Proceedings of 3rd Biennial conference of Sugarcane Research and Development Workers of India pp 264-274. Gupta B D 1959 Insect pests of sugarcane in India : The shoot borer Chilotraea infuscatellus Snellen. Indian Sugar 4: 387-397. Hasabe B M and Khaire V M 1994 Life history of early shoot borer Chilo infuscatellus Snellen. Bharatiya Sugar 20: 17-22. Issac P V and Misra C S 1933 The chief insect pest of sugarcane and method of control. Agricultural Live stock of India 3: 315-324. Kalra A N and Sunil Kumar 1966 Studies on biology of sugarcane shoot borer Chilotraea infuscatellus Snellen in Sriganganagar area of Rajasthan. Indian Journal of Agricultural Sciences 36: 443-449. Khan M Q and Krishnamurthy Rao 1956 Assessment of loss due to Chilotraea infuscatellus Snellen in sugarcane. Proceedings of International Society of Sugarcane Technology 9: 870-879. Khan A Rahaman and Singh D 1942a Binomics and control of sugarcane shoot borer Chilo infuscatellus Snellen in sugarcane in Sriganganagar of Rajasthan. Indian Journal of Agricultural Sciences 36: 443-449. Khan A Rahman and Singh D 1942b Studies on dead hearts caused by different species of sugarcane borers in Punjab. Indian Journal of Entomology 4: 77-85. Lakshminarayana K 1983 Pest Management in Andhra Pradesh In ‘ Sugarcane Pest Management in India” (eds. Balasubramanyan M and Solayappan A R). Tamil Nadu Cooperative Sugar Federation, Madras pp 63-70. Mukunthan N and Jayanthi R 2001 Entomology and Nematology. Annual Report, Sugarcane Breeding Institute, Coimbatore pp. 51-52.

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Patil A S and Hapase D G 1981 Research on sugarcane borers in Maharashtra State. Proceedings of National Symposium on stalk borer pp. 165-175.Platinum Jubilee Souvenir, 1988 Ramakrishna Ayyar T V and Margabandhu V 1935 Moth borer Argyria sticticraspis of sugarcane in south India. Agricultural Live Stock of India 5 : 503-521. Roome R E, Chaddha G K and Padgham D 1977 Choice of oviposition by Chilo, the sorghum stem borer, Bulletin SORP 3, 115-131.Sardana H R 1997 Determination of economic injury level for early shoot borer, Chilo infuscatellus Snellen in late maturing variety of sugarcane. Annals of plant protection sciences 5 (3): 216-217. Saikia D K, Devroy T C and Dutta S K 1996 Biology and seasonal history of sugarcane early shoot borer Chilo infuscatellus Snellen. Journal of the Agricultural Science Society of North East India 9 (2): 155-158. Siva Rao D V 1960 Studies on the resistance of sugarcane early shoot borer Chilotraea infuscatellus Snellen. M.Sc.(Ag.) Thesis submitted to the Andhra University,Waltair. Siva Rao A V and Kamalakar Rao C 1963 Preliminary studies on some aspects of influence of certain climatic factors on borer population (Chilotraea infuscatellus Snellen) in sugarcane. Indian Journal of Sugarcane Research and Development 7: 164-167. Sunil kumar, Umamaheswari T and Venugala Rao 2003 Studies on the biology of early shoot borer, Chilo infuscatellus Snellen on sugarcane. M.sc (Ag) thesis submitted to the A. N. G. Ranga Agricultural University, Hyderabad. Usman S, Sastry K S S and Puttarudraiah M 1957 Report of the work done on the control of sugarcane borer. Department of Agriculture Publication, Mysore pp. 69. Venugopala Rao N 1998 Monitoring and management of early shoot borer, Chilo infuscatellus Snellen in sugarcane. Ph. D thesis ANGRAU, Hyderabad.

DECLARATION

I, Dr. B. BHAVANI, Senior Scientist (Entomology), Regional Agricultural Research Station, Anakapalle hereby declare that the Research article entitled “Studies on the Biology of Sugarcane Early Shoot borer, Chilo infuscatellus Snellen under in vitro and in vivo conditions in North Coastal Region of Andhra Pradesh, India” is an original research work done by me as a part of my Ph.D work at Regional Agricultural Research Station, Anakapalle, Andhra Pradesh. It is further declared that this article or any part thereof has not been published earlier in any manner.

B.BHAVANI