The nutrition, growth, development and mortality of the cotton leafworm, Spodoptera littoralis, were followed on six different artificial diets. As compared with the reference diet of Poitout et al. (1972) (Entomologia exp. appl.15, 341–350), our new media exhibit some interesting technical features:
(1) The agar is replaced by a new gelling substrate of which two types exist: Korano gels 400 and 411.
(2) These gels allow the preparation of a dry, sterile and ready-to-use mixture in convenient plastic packings. The powder is obtained by grinding the insoluble components and the nebulization of the soluble ones. When needed, the powder is simply added to hot distilled water (60–70°C) and stirred.
Different conditioning processes have been tested and this work was carried out to ensure that the two Korano gelling powders have the same biological quality as agar. The prepacked diets have proven to be very easy to store and to handle, and overall they are quite efficient and time-saving. Furthermore, they are much cheaper than the laboratory-prepared control diet. They supported the complete and normal development of S. littoralis, and even at a slightly better rate than agar-containing diets (M1 and M2b diets).