Experiments concerning the Utilization of the Bean Basic Semisynthetic Media for Rearing Two Species of Cutworm, Agrotis ipsilon HUFNAGEL and A. fucosa BUTLER (Lepidoptera, Noctuidae)

The present writers have tried several experiments to determine whether the bean basic semisynthetic media and the improved rearing method for rearing the tobacco cutworm, Prodenia litura FABRICIUS, in the previous experiments can be adapted for the present artificial cultures of both the black cutworm, Agrotis ipsilon HUFNAGEL, and the turnip moth, A. fucosa BUTLER. 1. Both normal abult males and females which could lay viable eggs could be reared successfully from the second instar larvae of black cutworms on four kinds of media the kidney bean media, soy bean media, kidney-soy bean media and soy-azuki bean media, though the duration of larval growing period became longer and the percentages of pupation, emergence and the yield of adults obtained from the larvae initially used were lower than those from the control which was fed on the leaves of sweet potato. The kidney bean media seemed to be more suitable for the artificial rearing of this insect as compared with three other bean basic media. At 26℃., the durations of larval, prepupal and pupal period were 18.5, 2.2 and 11.0 days, respectively. The percentages of pupation, emergence and yield of emerged adults from the initial second instar larvae were 66.0, 30.3 and 20.0 %, respectively. The pupal weights were 291.0 mg., for males and 303.0 mg. for female. The number of eggs laid per female was 234 and the hatchadility of these eggs, 50.2 %. 2. Using the kidney bean media, which seemed to be the most promising medium, three successive generations of the black cutworms were reared successfully as shown in Table 2. However, the results were slightly inferior to those in the previous experiments of Prodenia lilura FABRICIUS. 3. In the experiments in which the larvae were reared individually using one larva per glass tube, the numbers of moulting and larval instars passed, duration of each instar period, width of head capsule of each instar were observed more exactly than in the case of the above culture. The percentages of pupation, emergence and yield of adults were also examined accurately in this experiment. These results were considerably superior to those obtained in the above ones cxcept that the duration of larval period was longer. 4. Three successive generations of turnip moths have been reared using the same procedure and kidney bean media as used in the successive rearing of the black cutworms. Although full data on the third generation could not obtained by this time, it was expected that these successive generations could be reared successfully as in the rearing of thc black cutworms. The life history data of the turnip moth reared on the kidney bean media at 26℃. were as follow. The durations of larval, prepupal and pupal period were 28.6, 2.9 and 15.6 days, respectively. The percentages of pupation, emergence and yield of adults were 77.8, 83.3 and 64.8 %, respectively. The pupal weights were 438.8 mg. for males and 488.8 mg. for females. The number of eggs laid per female was 543.8 and the hatchability of these eggs, 76.1%.