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Persea bombycina Kost. Commonly known as Som, is the primary host plant of golden silk
producing Muga silkworm (Antheraea assamensis Helfer. ). Muga is very sensitive to the odour of
toxic chemicals, temperature & humidity. Muga worms has been dying prematurely for years due to
air pollution. Besides pesticides, insecticides & herbicides seasonal change is effecting muga
production with food plant. Sands & sediments carried by flood waters covered som bushes up to
three to four feet. After the desertification & being affected by stagnant flood water som plant dies
within few months. This has been happening for years and most of muga rearing areas are now
almost free of this cultivation. Moreover due to climate change outbreaks of various disease causing
microbes may occur to the host plants along with other microbes. A study was conducted to study the
climatic factor and types of mycoflora present on the som growing areas of Goalpara district during
February,2014 to July, 2014. A total of 7 fungal species from air, 12 fungal species from
phylloplane, 16 fungal species from rhizosphere and 11 fungal species isolated from nonrhizosphere
soil of som plantation area of the study area which show cyclic pattern of occurrence.
The major mycoflora which dominates the air, phylloplane, rhizosphere & nonrhizosphere soil of
som cultivation area were Rhizopus spp. & Aspergillus spp. The study also reveals that climatic
factors such as temperature, humidity & rainfall are also responsible for occurrence of certain
mycoflora which effects the Som & ultimately the muga silkworm. Hence recent urbanization,
deforestation, pollution & climate changes have all pushed muga silkworm to the danger of declined
production & to the very sustenance.
Keywords: Persea bombycina, Climatic factors, Seasonal variation, mycoflora, Goalpara.