This is the first study to clearly demonstrate the potential on the use of potassium alum as a friendly-insecticide against Blattella germanica (L.). This German cockroach is in first appendance to American cockroach. In our laboratory, we tested the common potassium alum for controlling B. germanica (L.). Starved adult and nymph stages were left to feed with crashed pellets of potassium alum. The mortality recorded as LT50, the younger nymph first, second, third and fourth instars were died within 5 days after feeding. Non- Gravid and gravid females were quit susceptible and decrease in their survival to high extent with LT50 12 days. The wonderful effect was found that the effect of the potassium alum is extending effect to the egg capsules especially if the female started to eat at the beginning of the extrusion no nymphs could be emerged at all. The protease activity of the female cockroaches that fed upon potassium alum was greatly decreased during her reproductive cycle which greatly reduced the percentage of emergency of nymphs especially if it starts feeding on potassium alum at the day 1 of the reproductive cycle i.e. the egg case start to protrude from the abdomen. These would be a great potential in increasing oocyte resorption with no chance for new offspring to live i.e. decreased the protein content of the oothecae to low level. The results revealed that the female and male need to ingest 1, 1.9 mg of potassium alum respectively to induce 100% mortality after 18 days for female and 1 month to male after treatment. The potassium alum had to be ingested by the cockroaches to induce mortality. The potential applications of this novel technique will be discussed.
Keywords: environmentally friendly insecticide, potassium alum, Blattella germanica
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