S. Manochaya is a budding researcher, currently working as a project fellow in Biodervisity Bioprospecting and Sustainable Development under Institute of Excellence in Department of Microbiology, University of Mysore. A post graduate in Microbiology, she had earlier worked with M/s. Healtline Pvt. Ltd., Sericare Division, Bangalore as R &D Officer and involved in DBT project “Silk Protein blend film for burn wound management” and in the development of other neutraceutical products. She is interested in Agricultural and Medical Microbiology for herbal drug development. Mr. J. Justin Kumar works with Central Sericultural Research and Training Institute, Mysore, India. His research interests include silkworm pathology and application of bio-molecules in silkworm disease management. They can be contacted at: email@example.com & firstname.lastname@example.org
Aspergillus is a facultative fungus and is able to live saprophytically in the silkworm rearing environment like soil surface and rearing appliances, silkworm faeces etc (Aoki, 1971; Ayuzawa et al., 1972). These form the source of the fungus and thus disease spreads rapidly. Though Aspergilli are saprophytic, they are reported to be pathogenic to several insects in addition to Bombyx mori (Govindan et al., 1998). The early instars i.e., first and second instar silkworm larvae are more susceptible and later stage silkworms are fairly resistant to this diseases. High temperature and high relative humidity conditions maintained during young stage are reportedly contributing factors to greater disease incidence during young age (Govindan and Devaiah, 1995). Aspergillus flavus Link. and Aspergillus tamarii Kita are commonly found strains in India.
Systematic position of the pathogen
Mode of infection
Physiological changes in infected larvae
Incidence and loss
Chinnaswami (1983) reported that in Karnataka, India the percentage of disease incidence ranged from 5.32 (February-March) to 21.36% (July-August). In Thailand, incidence of Aspergillosis is more during June and August and less during September (Aoki, 1971). The disease is noticed on first to third instar larvae during January to February and on fourth and fifth instar larvae during July (Aoki et al., 1972). Singh et al., (2004) reported that the maximum crop loss per 100 layings (50000 larvae) was 1.35±0.73 to 1.61±1.46 kg cocoons. Incidence was higher in bivoltine silkworm rearing than in multivoltine and cross breed.
Aoki K (1971) Silkworm diseases in Thailand. Bull. Thai. Seric. Res. Trg. Inst. 1: 102-108.
Aoki K, Isarangkul L and Sinchaisri N (1972) On silkworm diseases, especially pebrine and Aspergillus diseases found in 1971. Bull.Thai Ser.Res.Trani. Centre, 2: 72-76.
Graham HD and Graham EJF (2007) Inhibition of Aspergillosis parasiticus growth and toxin production by garlic. J. Food Safety 8(2): 101-108.
Singh GP, Selvakumar T, Sharma SD, Nataraju B and Datta RK (2004). Estimation of crop loss due to aspergillosis and pathogenicity of Aspergillus to Silkworm, Bombyx mori L. Sericologia 44(3): 321-326.