2009 Volume 53 Issue 3 Pages 77-83
The pH of the artificial diet used for insect rearing generally affects the bacterial contamination of the diet. We examined the effect of adding hydrochloric acid (HCl) to the artificial diet of Euscepes postfasciatus on bacterial contamination of the diet. First, we reared the species using diets prepared with various HCl concentrations to determine the concentration that does not adversely affect the survival and development of E. postfasciatus. The use of HCl at a lower concentration than 0.12% does not remarkably affect insects. Next, we compared bacterial contamination among the following four groups. Insect eggs were inoculated with three of these groups: 0.072% HCl diet, 0.036% HCl diet, and diet without HCl added (positive control). In the fourth group, HCl was not added to the diet, and the eggs were not inoculated (negative control). The contamination rate in the 0.036% diet was not significantly lower than in the positive control, whereas the rate in the 0.072% diet was lower than in the positive control but not significantly higher than in the negative control. We concluded that adding HCl to the artificial diet of E. postfasciatus was quite effective for preventing bacterial contamination of the diet.
