Development and Efficacy of Silica-Based Anti-Insect Fumigant Sachet for the Management of Callosobruchus chinensis (L.) (Coleoptera: Bruchidae)

This study was conducted to develop a new silica-based anti-insect fumigant
sachet to control C. chinensis, a common storage pest of green gram (Vigna radiata).
This insect causes serious damage to stored pulses, so it is important to find a safe and
effective method to control. In this, a fumigant sachet was prepared using silica and
diallyl disulfide, a natural compound derived from garlic. The main aim was to check
how well this fumigant works under different storage conditions. For this, three
different container sizes were used: 250 ml, 500 ml, and 750 ml.
The experiment was done both with food (green gram seeds) and without food
to see how food affects the fumigant action. Insect mortality and egg emergence were
recorded at 24, 36, and 48 hours. The results showed that the fumigant was very
effective in killing insects. The number of dead insects increased over time. At 24
hours, only some insects died; at 36 hours, the mortality increased; and at 48 hours,
100% mortality was observed across all treated conditions. This showed that the
fumigant worked very well in all container sizes. In control samples (without
fumigant), very few insects died, which proved that the fumigant was responsible for
killing them.
The study also showed that egg emergence was significantly lower in treated
samples than in controls. This means the fumigant not only killed adult insects but
also stopped their reproduction. It may have affected egg development or larval
growth, helping prevent further infestation. Another important part of the study was to
check whether the fumigant affected the quality of green gram. The results showed no
major changes in moisture, protein, carbohydrate, or fat content. The germination
percentage was also 100% in both treated and untreated samples. This means the
fumigant did not damage the grains and was safe to use.
GC–MS analysis of garlic oil showed that it contained sulfur compounds like
diallyl trisulfide and diallyl disulfide. These compounds are known for their strong
insecticidal properties and played an important role in killing the insects. This study
showed that the silica-based fumigant sachet was very effective, safe, and ecofriendly.
It completely killed insects, reduced egg emergence, and did not affect grain
quality. it can be used as a good alternative to chemical pesticides for storing grains.