There are now two strains of the European corn borer, Ostrinia nubilalis (Hübner), in Quebec. The strain normally found produces one generation while the more recently introduced strain produces two generations per year. Both strains have been characterized and compared with corn borer strains from Ontario and New York State. The two attributes of the recently introduced strain that promote the development of a second generation are (1) early emergence in the spring with less intense diapause and (2) a lower critical photoperiod for diapause induction. The latter characteristic allows pupation of first generation larvae. Field and laboratory tests on the pheromone response of adult male moths demonstrated that the origin of this recent introduction was New York State.
The importance of 10 B vitamins for growth and survival of the nymphs of Acheta domesticus (L.) was tested by single omission. Thiamine, pyridoxine, nicotinic acid, pantothenic acid, choline, and biotin were found to be essential, the omission of any one of them resulting in very poor growth and in little or no survival to the adult stage. The absence of riboflavin or inositol retarded growth significantly, but a large percentage of the nymphs still reached the adult stage. The lack of folic acid resulted in a significantly longer nymphal stage and in greater mortality towards the end of that period. Only the omission of p-aminobenzoic acid had no significant effect on the nymphs.
Lipid other than sterol improves the growth and development of nymphs of Acheta domesticus (L.), as shown by the effect of adding wheat germ oil and linoleic acid to the diet. Such lipid is also necessary for reproduction: the effect appears to be on the male, but may also be on the female.
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