Int.J.Curr.Microbiol.App.Sci (2021) 10(03): 596-605 International Journal of Current Microbiology and Applied Sciences ISSN: 2319-7706 Volume 10 Number 03 (2021) Journal homepage: http://www.ijcmas.com Original Research Article https://doi.org/10.20546/ijcmas.2021.1003.077 Cross Infectivity of Glyphodes pyloalis Walker Infested Mulberry Leaves on the Rearing Performance of Silkworm, (Bombyx mori L.) Abeera Imtiyaz1*, K. A. Sahaf1, Shabir A. Bhat1, ShaheenGul2, Iqra Rafiq1, Z. I. Buhroo1 and S. Maqbool3 1College of Temperate Sericulture, 2MFCRC, SKUAST-K, Khudwani, 3Division of Statistics, FOA, SKUAST-K, Wadura, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir Srinagar, J & K, India *Corresponding author ABSTRACT In the present study, susceptibility of the silkworm, Bombyx mori to the pathogens of K e yw or ds mulberry pest Glyphodes pyloalis was ascertained. Silkworm, Bombyx mori inoculated with the pathogens isolated from G. pyloalis (Microsporidian and Nuclear Polyhedral Bombyx mori, Cross infectivity, Virus) showed high mortality at larval and pupal stages. Silkworms inoculated with Glyphodes pyloalis, Microsporidian showed mortality of 53.66% at larval stage whereas silkworms inoculated Mulberry , with Nuclear Polyhedral Virus showed mortality of 61.00% at larval stage. The survival Silkworm rate and pupation rate besides the other economical characters were also affected in the inoculated batches of silkworm. The v larvae inoculated with the pathogens of silkworm Article Info showed mortality of 90.64% and 92.00% due to Microsporidian and Nuclear Polyhedral Virus inoculation respectively. The study has revealed that G. pyloalis besides being a Accepted: major pest of mulberry causing severe damage to the leaves also acts as alternate host for 14 February 2021 the pathogens causing diseases of silkworm. As such this pest needs to be managed to Available Online: prevent loss to the mulberry plantations as well as spread of silkworm disease causing 10 March 2021 pathogens. Introduction sericulture on sound economic lines. From the economic point of view, moriculture coupled Sericulture is an art of rearing silkworms for with silkworm rearing remains a highly the production of cocoons which is the raw labour intensive activity providing vast scope material for silk production. India has a for employment. There are several factors that unique distinction of being the only country hinder the productivity as well as quality of producing all the four known commercial mulberry leaves, among them incidence of silks namely Mulberry, Tasar, Eri and Muga. pests and diseases acts as major one. The Mulberry (Morus sp.) is the only host plant of plantation is ravaged by different pests and silkworm, Bombyx mori L. The production on diseases and as many as 11 major and 10 scientific lines is essential for organizing minor insect pests have been reported from 596 Int.J.Curr.Microbiol.App.Sci (2021) 10(03): 596-605 Jammu and Kashmir (Sharma and Tara, 1985; Leptomonas spp. infect silkworm Bombyx Khan et al., 2004). Over 300 insect and non- mori and causes microsporodiosis (Jolly, insect species of pests are known to attack 1986 and Abe, 1978). There are other mulberry (Narayanaswamy et al., 1996; microsporidia besides Nosema bombycis that Reddy and Kotikal, 1988). From Karnataka infect silkworm, Bombyx mori, which is alone more than 100 while from Maharashtra generally thought to be the result of cross 20 insect pests have been reported so far from infection of microsporidia in silkworm and mulberry (Sathe and Mulla, 1999). A number other insects (Kishore et al., 1994; Bhat et al., of parasitoids and predators have been 2009). recorded on this pest from most parts of Jammu and Kashmir and elsewhere in Asia Bombyx mori Nucleopolyhedrovirus (Mathur, 1980). 53 natural enemies (BmNPV) is the most harmful virus causing comprising of 37 parasitoids, 6 predators and severe economic loss to the sericulture 10 pathogens are known to attack mulberry industry (Ponnuvel et al., 2003). This disease leaf Webber (Manjunathgowda et al., 2005) is commonly termed as grasserie/ jaundice/ The presence of various silkworm pathogenic milky disease/fatty degeneration or hanging microbes have been reported in Bihar hairy disease. The Glyphodes pyloalis Walker is the caterpillar (Diacrisia oblique) which is a habitual host of non-occluded viruses major pest of mulberry (Sharma et al., 1989). pathogenic to the silkworm Bombyx mori L. (Watanabe et al., 1988). Silkworms are susceptible to a number of diseases caused by different infectious agents Materials and Methods such as protozoan, viral fungal and bacterial diseases. It is the main factor seriously Collection of mulberry pest G.pyloalis affecting the cocoon production. During the Walker silkworm rearing, the silkworm comes into contact with pathogenic agents (viz., A survey was conducted of the mulberry Microsporidian, virus, fungi and bacteria) farms of College of Temperate Sericulture which accounts for considerable loss to (CTS), Mirgund and Mulberry Farms of cocoon production (Samson 1995). Mulberry Sericulture Development Department, J&K (Morus sp.) is the only host plant of located at Mirgund and Tulsibagh, Srinagar silkworm, Bombyx mori L. Different mulberry respectively during Spring 2017. Survey pests and lepidopterans were known to harbor during the incidence of Glyphodes pyloalis microsporidian (Sharma et al., 1989; Srikanta, Walker was conducted by adopting fixed plot 1987 and Chandra, 1987). Ishihara &Iwano, method. In each mulberry garden five micro (1991) reported that the perpetual incidence plots were considered (4 at corners and 1 at of microsporidian infection in silkworm may the middle of mulberry farm). 15 randomly be due to various sources of secondary selected plants in each micro plot were contamination or cross infection from the observed for pest infestation (75 plants/ alternate hosts. mulberry farm). The per cent pest infestation was calculated by using the formula: The periodic occurrence of Pebrine disease in the rearing field indicates the possibility of PI = No. of infested leaves x 100 cross infection of Pebrine spore from the Total no. of leaves observed other alternate host, (Bashir and Sharma, 2008). Nosema spp, Pleistophora spp and The healthy samples collected during survey 597 Int.J.Curr.Microbiol.App.Sci (2021) 10(03): 596-605 were brought to the laboratory of CTS, observed during the rearing process was Mirgund which were reared and utilized for recorded. further experiments. However the diseased and dead samples were taken to isolated place Results and Discussion and processed/homogenized and smear prepared thereof was centrifuged for 5 Incidence of Pathogens in G. pyloalis under minutes at 3000 rpm and then examined under natural conditions microscope (600x) to observe presence of pathogens. The morphological details of the Survey conducted during the year 2017 at pathogens were recorded for their various locations viz., CTS Mirgund, SDD identification. Mirgund and SDD Tulsibagh, to ascertain the incidence of pathogens in Glyphodes pyloalis Studies for the susceptibility of silkworm, showed presence of Microsporodia (Nosema Bombyx mori to the pathogens of G. pyloalis bombycis) and Nuclear Polyhedrosis virus (NPV). The percent incidence of these Under this experiment the pathogens pathogens in G.pyloalis larvae is presented in collected/isolated from G. pyloalis were Table 1which showed mean incidence of tested for their pathogenicity to the silkworm, Nosema bombycis in G.pyloalis as 1.11%, B. mori. Disease free layings of silkworm race 2.22%, 1.99%, 3.33% and 4.22% during the (CSR4) obtained from Division of Sericulture months of June, July, August, September and Crop improvement of CTS, Mirgund were October respectively. So for as stations are reared in Silkworm rearing laboratory CTS, concerned, the maximum mean incidence was SKUAST-K Mirgund during Autumn recorded in CTS Mirgund (3.59%) followed (September-October 2017) upto 3rd instar. by SDD Mirgund (3.19%) and minimum Immediately after 3rd moult larvae were mean incidence was recorded in SDD inoculated with the pathogens isolated from Tulsibagh (0.92%). The mean incidence of the Glyphodes pyloalis Walker. For each NPV in G.pyloalisis presented in table 2 as inoculating pathogen six replications were 1.10, 2.44%, 4.21%, 5.10% and 5.99% during maintained with 150 worms in each the months June, July, August, September and replication. Required concentration was October respectively. Among the stations, the prepared (1×106 spores/ml) from stock maximum incidence was recorded in SDD solution and quantified to estimate the spore Mirgund (4.66%) followed by CTS Mirgund concentration following standard (4.39%) and the minimum incidence were haemocytometer count (Cantwell, 1974). One recorded in SDD Tulsibagh (2.26%). The low ml of inoculums was smeared on mulberry incidence of the disease at SDD, Tulsibagh is leaves, the leaves were allowed to shade dry mainly due to less silkworm rearing in the and then fed to the third instar silkworm vicinity of the area. larvae of CSR4 breed immediately after 3rd moult. The larvae were allowed to feed on the Effect of pathogens isolated from G. treated leaves for 12 h to ensure complete pyloalis on Survival rate and economic consumption of the contaminated leaves. parameters of silkworm, Bombyx mori L. After 12h, the larvae were fed with normal mulberry leaves and reared till cocooning. A The effect of pathogens Microsporodia control batch of healthy