Evaluation of Bacillus thuringiensis cultured in wastewater sludges against the potato tuber moth (Lepidoptera: Gelechiidae)
Saour, George; Al-Mariri, Ayman; Hashem, Ali
Abstract Municipal wastewater sludges from urban, industrial, and rural regions, Luria Bertani (LB) and LB enriched with salts (LB + salts) media were used for Bacillus thuringiensis subsp. kurstaki HD-1 (Btk) at bench scale production. The highest concentration of delta-endotoxin was obtained from rural sludge, while a significant decline in delta-endotoxin synthesis was recorded in LB + salts medium. The entomotoxicity of Btk cultured on rural sludge against the potato tuber moth was higher, even at low spore concentrations, compared to LB and LB + salts media. The Btk fermentation process using sludges resulted in higher resistance, in term of residual insecticidal activity, to UV-A and B radiation. Data reported here proved that Btk suspension produced from municipal wastewater sludges of different mineral salts content was very efficient against larvae of the potato tuber moth under either field (high UV radiation) or storage conditions.