1. Introduction
Acidification of rain-water is identified as one of the most serious environmental problems of transboundary nature1,
included in Indonesia. Rainfall in Indonesia is categorized as acidic rain. Among 31 samples of rain water from 31
observation stations throughout Indonesia, it appears that 22 of them are already below the threshold limit value of
normal rainwater pH of 5.6. This condition indicates that the rainfall is already acidic2. The cause of acid rain due to
air pollution from the presence of CO2, SO2 and NO2 has long been experienced world wide3,4. The higher pollutants
are caused by pollutants from vehicles, factories, etc., whereas the carbonmonooxide (CO) is a result of
incompletecarbon compounds combustion5.EPA stated that approximately 68% of SO2 in the atmosphere around
U.S. areas occur from electrical utility, 25% from industrial processes and fuel combustion, 4% from transportation,
and 3% from commercial/industrial/residential6.Whereas Re Velle & Re Velle stated that petroleumcontains
between 0.1% to 3% of sulphur, and 0.4% to 5% of coal5. When the fossil fuel is burned, the sulphurwill be oxidized
to sulphur dioxide (SO2). In the air, sulphuroxide is transformed into sulphuric acid. Sulphur dioxide oxidation is
most common in clouds and especially in heavily polluted air. Sulphuric acid mixed with water vapor in the
atmosphere will cause acid rain1. Acid rain that maybe dangerous for living organism, especially Bombyxmori L.
But, in other hands, polluted air brings many nutrients that needed for plants7, included mulberry plant growth. So, it
is very interesting to find out the effect of acid rain to silkworm life. Effect of acid rain on plants and the effect on
defective cocoon of mulberry silkworm has not been investigated.