International Journal of Art & Humanity Science (IJAHS) e-ISSN: 2349-5235, www.ijahs.com Volume 2 Issue 6, (Nov-Dec 2015), PP. 43-50 On the recovery of pupae of uzi fly, Exorista sorbillans (Weidmann) in silkworm (Bombyx mori L) rearing house and surroundings Anjana Reddy. B., Vinayak Reddy, B., Lakshminarayana Reddy. P., Sujatha. B., *Shanthan Babu. M. A. and Sankar Naik. S. Department of Sericulture, Sri Krishnadevaraya University, Anantapur- 515 003, India. ⃰ Regional Sericultural Research Station, CSB, PB. No. 50, Anantapur – 515 001, India. ABSTRACT Information on the availability of uzi fly (Exorista sorbillans Wiedemann) pupae in the environs of the silkworm rearing house offers an important base for silkworm cocoon crop protection strategies and further management/avoiding uzi fly infestation in the next generation silkworm rearing cycle. A survey was conducted to study the availability of uzi fly pupae in three rearing environs of silkworm (Bombyx mori) viz., i. floor of the silkworm rearing house, ii. silkworm rearing bed and iii. surroundings of silkworm rearing house in Anantapur district of Andhra Pradesh. One hundred farmers were selected for the survey study. Survey was conducted for six consecutive silkworm rearing cycles in a year; 2 silkworm rearing cycles in each season, summer, rainy and winter. Statistically analyzed data indicated that the availability of uzi fly pupae in number of uzi fly pupae/m2 in three silkworm rearing environs was high during rainy season (20 ± 3.010), followed by winter (12 ± 1.893) and summer (6 ± 1.055). Availability of uzi fly pupae was high in silkworm rearing bed and surroundings of silkworm rearing house followed by floor of silkworm rearing house. The availability of uzi fly pupae in the environs of the silkworm rearing questions the effectiveness of present technologies and/or its adoption rates at farmers level and further hints at a serious threat to the silk industry as the pupae attack next generation of silkworm rearing cycle after emerging as adult uzi fly. KEY WORDS: Uzi fly, Exorista sorbillans, pupae, probable sources. Introduction: Sericulture flourished well up to 1980. Later it experienced threats from diseases alone, causing a moderate to complete cocoon crop loss. Added, a new threat was encountered by south Indian sericulture through uzi fly during 1980 (Anonymous, 1980). The pest has been recognized as tachinid, Exorista bombycis (Louis), popularly known in India as 'uzi fly', is an endoparasitoid of Bombyx mori (Mukherji, 1919; Jameson, 1922). The uzi fly, Exorista bombycis has been recognized as Exorista sorbillans (Wiedemann) (= Exorista bombycis = Tricholyga bombysis = Tricholyga sorbillans = Tachina sorbillans; Sengupta et al., 1990). E. sorbillans, existed in the north-eastern and eastern states of India for more than a century (Becher, 1889) was introduced into Karnataka, caused severe damage, accounting for about 60% of the total raw silk production in 1980’s (Jolly, 1981). By 1982, the fly was also recorded in the neighboring states of Andhra Pradesh and Tamil Nadu (Kumar and Jolly, 1986). Availability of silkworm larvae throughout the year, favorable climatic conditions, 43 | P a g e International Journal of Art & Humanity Science (IJAHS) e-ISSN: 2349-5235, www.ijahs.com Volume 2 Issue 6, (Nov-Dec 2015), PP. 43-50 transportation of uzi infested cocoons from infested areas into un-infested areas in these states hastened the spread of the pest, resulting in really a serious threat to the silk industry. According to a field survey, the uzi infestation level in sericulture was 9.0 - 40.0% during 1980-83, 9.18 – 22.02% during 1984-87 (Kumar et al., 1987a, b) and 5.13 – 15.4% during 1988-90 (Kumar et al., 1993). The female uzi fly lays eggs on the surface of silkworm larval body. The eggs hatch into small maggots which pierce the host's integument and devour the body contents, resulting in the death of the host (Datta and Mukherjee, 1978; Kumar, 1987). Attracted by its economic importance, various researchers published on different aspects of uzi fly including integrated pest management (IPM). Works on uzi fly include its fertility, fecundity, induction of sterility and control measures (Isarangkul and Scinchaisri, 1971; Sriharan et al., 1971; Datta and Mukherjee, 1978; Kumar et al., 1985; Jolly, 1981). Combating with the uzi fly has attained a great responsibility of pest control scientists. IPM of uzi has covered almost all stages in the life cycle uzi fly. IPM of uzi fly covered basic components like physical methods, avoiding the entry of uzi female fly into rearing house (Kumar et al., 1993); chemical treatments aiming at killing eggs of pest (Kumar et al., 1993) and release of hyper- parasitoids to control uzi fly pupae (Kumar et al., 1993). However, it is obvious that uzi menace is not checked completely so far. It hints that uzi fly is escaping from IPM components either in one stage of life cycle or several stages. Uzi pupa is one such stage where much emphasis is not given for complete control as release of hyperparasitoids, Nesolynx thymus alone is not fully practiced and a wide gap exists in adoption of this component of IMP (Shaktivel et al., 2012). It is therefore presumed that uzi pupae are escaping in one way or the other from the hyper-parasitoid, Nesolynx thymus and the uzi cycle is continued. Therefore, probable availability of uzi pupae in the silkworm rearing house and its near vicinity is examined in the present study, in Anantapur district of Andhra Pradesh, a sericulture leading district. Material and Methods: Anantapur, one of the traditional sericultural districts of Andhra Pradesh, India was selected for the present study from which, 100 farmers were randomly selected emphasizing equal importance to all the sericulture Mandals of the districts. The main objective of this study was to examine the availability of uzi fly pupae in the environs of the silkworm rearing house. These pupae definitely attack the next silkworm rearing cycle after emerging as adult uzi flies. In total three probable sites of uzi fly pupal availability were identified viz., 1. floor of silkworm rearing house, 2. silkworm rearing bed and 3. surroundings of silkworm rearing house. The area of the three environs was measured in m2 and recorded. The collection/recording was done immediately after 24 hours of silkworm cocoon crop harvest, as the uzi fly maggots pupate after 20 hours of the maggot’s coming out of infested silkworm larva. Uzi fly pupae were collected from silkworm rearing house floor and surrounding of silkworm rearing house. The total number of uzi fly pupae were counted for each environs of silkworm rearing house floor and surrounding of silkworm rearing house and recorded. The availability of uzi fly pupae in unit area (m2) was later calculated by dividing total number of uzi pupae in particular environ by total area of that particular environ. For recording/calculation of number of uzi pupae available in silkworm rearing bed was however, resorted to sample collection. From the total area of silkworm rearing bed, a sample of 10% area was randomly selected in 10 parts of shoot rearing racks. Available uzi fly pupae were collected, counted and recorded. The availability of uzi 44 | P a g e International Journal of Art & Humanity Science (IJAHS) e-ISSN: 2349-5235, www.ijahs.com Volume 2 Issue 6, (Nov-Dec 2015), PP. 43-50 fly pupae in unit area (m2) of silkworm rearing bed was later calculated by dividing total number of uzi pupae in sample area of silkworm rearing bed by total area of silkworm rearing bed. Results: Data on the availability of uzi pupae in all three spots (silkworm rearing house floor, silkworm rearing bed and surroundings of silkworm rearing house) in terms of number of uzi fly pupae per unit area are depicted in Fig. 1. Perusal of Fig. 1 indicated highest number of uzi fly pupae (28 pupae/m2 ± 10) in the silkworm rearing bed. Lowest number of uzi fly pupae in both floor of silkworm rearing house (9 pupae/m2 ± 8) and its surroundings (9 pupae/m2 ± 4). The differences in the number of available uzi fly pupae between the silkworm rearing bed and both the silkworm rearing house and its surroundings were statistically highly significant (p < 0.01, Fig. 1). Data on the uzi fly pupal availability (number of uzi pupae recovered/m2) in three collection spots (floor of silkworm rearing house, silkworm rearing bed and surroundings of silkworm rearing house) in Anantapur district during three different seasons (summer, rainy and winter) have given clear cut trends further. Data on the number of uzi pupae/m2 in the floor of silkworm rearing house (Fig. 2) clearly indicated high availability of uzi pupae during rainy season, followed by winter and summer seasons, the differences being statistically significant at 1% level. The other uzi fly pupal recovery points studied viz., silkworm rearing bed and surroundings of silkworm rearing house, however, offered a different trends. Thus, highest number of uzi fly pupae were observed during rainy season, in common (Fig. 3 and 4) followed by that during winter season. Lowest quantum of uzi fly pupae were recovered during summer season in these two uzi fly pupal recovery points, silkworm rearing bed and surroundings of silkworm rearing house. Differences in number of uzi fly pupae recovered between rainy and winter seasons with silkworm rearing bed and surroundings of silkworm rearing house were not significant, but significant (at 1% level) between summer and the other two seasons (rainy and winter, Fig. 3 and 4). Discussion: The uzi fly, Exorista sorbillans (Wiedemann) is an endo-parasitoid on the larvae of the silkworm, Bombyx mori L. (Jameson, 1922), causing enormous damage to commercial silkworm cocoon crop in several silk producing countries, including India (Kumar et al., 1993; Doddamani et al., 1997; Kasi Reddy and Krishna Rao, 2009; Chavan, 2012; Gangadhar et al., 2012; Joshi et al., 2013).