Bioassay of Rongbao (Active Ingredients of Calcium Cyanamide) Against Housefly Maggots 107
poses and liberates more hydroxyl ion to raise
pH value in the mixed system. Our simple study
design, based on pH value test in the larval rear-
ing medium, absolutely confirms our hypothesis
presented above. In our study, results from analy-
ses of relation between CC and pH value demon-
strated a positive lineal pattern of increase in pH
value in response to the increasing concentration
of CC. Data from blank control group evidenced
background pH value in larval rearing medium.
pH value occurred in blank control group among
three repeats fluctuated in small size among 3
days. This difference is interpreted as due to the
influence of larval rearing medium environment
upon the pH value of blank control group. How-
ever, no pH value fluctuations in treatment group
during the experimental period was observed.
Nutrient-rich substrates such as animal ma-
nure and human excreta provide an excellent de-
velopmental substrate for maggots’ development
and growth. However, recent research suggests
that the acidity of rearing substrates may also af-
fect the development of larval flies. The appli-
cation of sodium bisulfate to calf bedding mate-
rial indirectly reduced housefly larval survival.
Acidification as a mode of fly management can
be beneficial to many areas of a dairy facility, es-
pecially for areas housing newborn calves. By re-
ducing larval density, calf housing areas can po-
tentially serve as less attractive sites to adult flies
for laying eggs (oviposition) (Calvo et al. 2010 ).
When caring for larval rearing medium, pH level
should be kept moderate in order to maintain a
healthy environment for housefly maggots. If the
pH balances are broken, it could mean death for
maggots. This viewpoint is supported by our test
result. In our test, the application of CC to larval
rearing medium has shown to increase pH value
and maggots survival was significantly affected
after the chemical addition. But, it is still un-
known whether alkalization was responsible for
the reduction in maggots survival, thus, further
study is required to verify this phenomenon.Fig. 1 Effect of contents on pH values of larval rearing medium after CC dissolved in water. Little circles represent
observed value. Line represents the expected relationship between contents and pH. The relationship of contents and pH
value is described as the formula y = 43.33x + 6.61 ( R^2 = 0.95, p < 0.01)