Original Research Article……….. International Journal of Agricultural Invention (online available at www.agriinventionjournal.com)

International Journal of Agricultural Invention 2(1): 82-84: June, 2017 ISSN: 2456 – 1797 (P)

A note on parasitisation of top borer by Isotima javensis Rohwer (: Ichneumonidae)

*Arun Baitha1, G. M. Tripathi1, Ram Ji Lal1, Rashmi Nigam2

1Division of Crop Protection, ICAR-Indian Institute of Sugarcane Research, Lucknow, U.P., India 2Department of Plant Pathology, J. V. College, Baraut, Baghpat, U.P., India *Corresponding email: [email protected]

ARTICLE INFO ABSTRACT Original Research article Isotima javensis is a solitary ecto of the sugarcane top borer, S. exceptalis. It Received on April 15, 2017 attacks the prepupal stage and deposits an egg either on the prepupa or near its vicinity. The Accepted on May 25, 2017 extent of parasitisation was observed 2.12%, 4.28%, 7.14%, 5.88% and 5.23 % in I, II, III, IV and V broods of top borer, respectively. The contribution of mortality of pupae of the Article Authors Arun Baitha, G. M. Tripathi, Ram top borer by parasitisation is high in III and IV broods (Aug-Oct), the time when the brood Ji Lal, Rashmi Nigam infestation remains generally very high. The maximum female ratio (59.72%) was observed Corresponding Author Email in III brood of parasitisation followed by 55.20 % in IV brood. In I and II broods, however [email protected] more or less equal number of males and females can be observed in the field. Equality in the sex ratio at this time ensures fertilisation of almost all the females for retaining the PUBLICATION INFO vigour and vitality of the species. The absence of unfertilized parasites naturally removes International Journal of Agricultural the chances of parthenogenetic reproduction and thus the number of females gradually rises Invention (IJAI) in the succeeding season. It is concluded that there are several attributes of parasitoid i.e. RNI: UPENG/2016/70091 specific parasite of top borer; its life cycle is much shorter than its host; active throughout ISSN: 2456-1797 (P) the period of activity of the host and even it hibernates under north Indian conditions which Vol.: 2, Issue: 1, Pages: 82-84 make it a good biocontrol agent. It is suggested that parasitoid may be exploited in Journal Homepage URL biological control programme, more detailed study is required for mass multiplication in the http://agriinventionjournal.com/ laboratory on an alternate host, release technique and survival in the sugarcane field. DOI: 10.46492/IJAI/2017.2.1.18 KEYWORDS Sugercane, Top Borer, Parasititation HOW TO CITE THIS ARTICLE Baitha, A., Tripathi, G. M., Lal, R. J., Nigam, R. (2017) A note on parasitisation of top borer by Isotima javensis Rohwer (Hymenoptera: Ichneumonidae), International Journal of Agricultural Invention, 2(1): 82-84. DOI: 10.46492/IJAI/2017.2.1.18

Sugarcane top borer, Scirpophaga ecto parasitoid of the top borer, S. exceptalis. The excerptalis F. is a major pest of sugarcane in almost grub of this wasp was parasitizing the top borer all the important cane growing areas of India (Gupta prepupa at Pusa in 1925 and again at Delhi and 1959 and Sithanantham 2013). The pest passes Karnal in 1937 (Issac, 1937). Since then it has been through 5 to 7 broods in a year under north Indian reported from all over India and other countries like conditions (Kalra and David, 1967). The borer Pakistan, Burma and Bangladesh on top borer spends major portion of the life-cycle within the (Gupta, 1961 and Rahman, 1976). It attacks the plant tissues, the short period passed outside is either prepupal stage and deposits an egg either on the as adult or in the egg stage. The young caterpillars prepupa or near its vicinity (Avasthy and Tiwari, enter the leaf mid-ribs within a few hours of their 1978 and Kalra et al, 1980). The newly hatched hatching from the eggs, and after that the pest grubs gain access to the host pupa by biting its way remains hidden inside the plant tissue till its through the nest of 7 to 12 silken discs within 72 emergence as moths. However, immediately before hours after hatching (Gupta, 1954). Its economic pupation, the grownup caterpillar cuts an exit hole in utility was recognised only when it was first one of the top internodes for the emergence of moth introduced in the tropical region (Pugalur area in at later stage. This exit hole renders the grown up Tamilnadu) during the late fiftees. The parasite not caterpillar or the newly formed pupa vulnerable to only succeeded in establishing itself in the new area, parasitisation by Isotima javensis (Kalra and David, it also brought down the incidence of top borer from 1967). Top borer larva/prepupa has been recorded 37.4 per cent in 1957-58 to 10.8 per cent in 1960-61 parasitising by , I. javensis, Rhaconotus (Gupta 1960 and Raja Rao 1964). To gather scirpophagae, Stenobracon niecevillei/ deesae, knowledge on parasitisation and sex ratio of Isotima zehntneri (Gupta, 1958, Rahman, 1976 and javensis affecting prepupal stages of top borer, a Tanwar and Varma, 1997). I. javensis is a solitar study was undertaken at IISR, Lucknow.

International Journal of Agricultural Invention, 2(1): 82-84, June, 2017 82

A note on parasitisation of top borer by Isotima javensis Rohwer (Hymenoptera: Ichneumonidae)

of males and females can be observed in the field. MATERIALS AND METHODS Equality in the sex ratio at this time ensures fertilisation of almost all the females for retaining The study was conducted at IISR, research the vigour and vitality of the species. The absence farm during 2011-2012. Fortnightly, collections of of unfertilized parasites naturally removes the damaged shoots of top borer (thrice in each brood) chances of parthenogenetic reproduction and thus was from the I,II,III,IV and V brood at exit hole the number of females gradually rises in the stage (the stage before the emergence of moths) succeeding season. Numerous parasitoid (Insecta- from Ist week of March to February in variety Hymenoptera) species are known to manipulate the CoLk 8102. The collected shoots were dissected to sex ratio of their offspring in response to changing find out whether larvae/prepupae were parasitized environmental conditions. (Charnov 1982, King and if they parasitized, shoots were kept 1987 and Godfray 1994). Smith and DeBach (1942) individually in glass jars covered with muslin were of the view that the natural enemies cloths and observed for emergence of parasitoids. depends on the supply of hosts for the reproduction After emergence, sexes were separated on the and the probability that the effective reproductive presence of ovipositor of parasitoid. The total field rates rose when hosts were scarce. This is quite true parasitisation (by three parasitoids, Isotima, in the case of the top borer and its parasites. It is Rhaconotus, and Stenobracon) and parasitisation by concluded that there are several attributes of Isotima was analysed statistically. parasitoid i.e. specific parasite of top borer; its life cycle is much shorter than its host; active RESULTS AND DISCUSSION throughout the period of activity of the host and even it hibernates under North Indian conditions The extent of parasitisation was observed which make it a good biocontrol agent. It is 2.12%, 4.28%, 7.14%, 5.88% and 5.23 % in I, II, suggested that parasitoid may be exploited in III, IV and V broods of top borer, respectively biological control programme, more detailed study (Table1). The parasitisation of different broods top is required for mass multiplication in the laboratory borer by Isotima ranged from 5-6% and 9-20% on an alternate host, release technique and survival during Jan-May and July-Oct, respectively in in the sugarcane field. Punjab, U.P. and Bihar (Gupta 1954). The contribution of mortality of pupae of the top borer REFERENCES by parasitisation is high in III and IV broods (Aug- Oct), the time when the brood infestation remains Ahmad, T. and Mathur, I. D. (1945) The biology generally very high. The maximum parasitisation and ecology of Melcha ornatipennis Cameron, a was observed in III and IV broods of top borer parasite of the top shoot borer of sugarcane, compared to II and V broods at Sardarnagar, Scirpophaga nivella Fabr., Indian J. Ent., 7: 21-36. Gorakhpur (Anonymous, 1989). The maximum female ratio (59.72%) was observed in III brood of Anonymous (1989) All India Co-ordinated parasitisation followed by 55.20 % in IV brood Research Project on Biological Control of crop (Table 1). The over-production of female (in the pests and weeds (Research report 1987 to 1989):24 post-winter brood) in a species capable of pp. reproducing parthenogenitically should certainly have some significance. The parasitoid at this time Gupta, B. D. (1954) A note on the scope of is on the threshold of a season in which the slightest biological control of sugarcane pests. Proc. Bien. weakness in its attack might turn the scale in favour Conf. Sug. Res. and Dev. Workers Ind., 2: 229-235. of its host. Naturally, therefore, if the species is to survive, it has to be on the alert to attack as many Gupta, B. D. (1958) Some friends of sugarcane as of the host as possible, just when they start farmers Pt.I.Parasites on top borer, Scirpophaga pupating after hibernation (Ahmad and Mathur nivella F. Ind. Sug. 8(7): 439-444. 1945). It must be noted that the activity of S. excerptalis is very low at this time of the year. In I Gupta, B. D. (1959) of sugarcane in India, and II broods, however, more or less equal number III- Top borer, Indian Sug., 9: 127-150.

International Journal of Agricultural Invention 2(1): 2017 83 Arun Baitha, G. M. Tripathi, Ram Ji Lal and Rashmi Nigam

Table 1. Field parasitisation of different broods of sugarcane top borer by Isotima javensis

Brood Mean ± SE *Total Parasitisation by Female emergence Male Parasitisation Isotima javensis (%) emergence (%) (%) I 8.57 ± 1.34 2.12 ± 0.36 50.00 ± 17.68 50.00±17.68 II 6.57 ± 0.87 4.28±1.07 52.00 ± 14.22 48.00±14.22 III 22. 71 ± 3.32 7.14 ± 1.16 59.72 ± 4.71 40.28 ± 4.71 IV 18.21 ± 3.32 5.88 ± 2.12 55.20 ± 13.25 44.80 ± 13.25 V 9.84 ± 1.61 5.23 ± 0.81 51.12 ± 9.23 48.00 ± 9.23 *Three parasitoids, Isotima javensis, Rhaconotus scirpophagae and Stenobracon niecevillei

Gupta, B. D. (1960) An indigenous parasite Rahman, M. (1976) Natural enemies of the top- succeeds in controlling the sugarcane top borer, borer of sugarcane Scirpophaga nivella F. in Proc. 28th Ann. Conf. Sug. Tech. India, 1: 24. Bangladesh, Indian J. Ent., 38(2): 101-109.

Gupta, V. K. (1961) Identity and synonymy of an Raja Rao, S. A. (1964) Biological control of top Ichneumonid parasite of the top borer of sugarcane, borer (Scirpophaga nivella F.) of sugarcane at Scirpophaga nivella Fabricius (Hymenoptera, Pugalur (Madras State), Proc. 5th All Ind. Conf. Ichneumonidae), Indian J. Ent., 23: 7-9. Sug. Res. and Dev. Workers, 5: 597-602.

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Manuscript received on April 15, 2017, Accepted for publication on May 25, 2017

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