. Biology of the tobacco moth and its control in closed storage. Tobacco moth; Tobacco moth Control; Tobacco Storage Diseases and injuries. BIOLOGY OF TOBACCO }10TH A^D ITS CONTROL 11 served in the laboratory was 25 days. This occurred in October, and it is likely that this figure represents approximately the maximum duration of the pupal period obtaining in tobacco storages. SEASONAL HISTORY In the unheated warehouses in which the writers made their obser- vations the tobacco moth passed the winter as one-fourth-grown to full-grown larvae. Many of those that were full-grown had migrated to sh
. Biology of the tobacco moth and its control in closed storage. Tobacco moth; Tobacco moth Control; Tobacco Storage Diseases and injuries. BIOLOGY OF TOBACCO }10TH A^D ITS CONTROL 11 served in the laboratory was 25 days. This occurred in October, and it is likely that this figure represents approximately the maximum duration of the pupal period obtaining in tobacco storages. SEASONAL HISTORY In the unheated warehouses in which the writers made their obser- vations the tobacco moth passed the winter as one-fourth-grown to full-grown larvae. Many of those that were full-grown had migrated to sheltered places about the buildings, but the undeveloped larvae usually remained in the tobacco, where, dur- ing periods of warm weather, they were observed crawling in the tobacco leaves. It is possible that they did some feeding during such periods. The low winter temperatures experienced in Virginia and Xorth Carolina during the period of these studies (28° F. tobacco temperature and 9° warehouse tem- perature) did not appear to reduce materially the larval population. The full-grown larvae began to pupate in the to- bacco warehouses in March, and the records show the earliest emergences to have been as follows: In 1931, May 9; in 1932, April 24; in 1933, May 2; and in 1934 on April 26. The emergence of the spring brood proceeded at a rather slow rate until the advent of hot weather, approximately May 25. In the laboratory this emergence covered a wide span of time—for example, in 1932 from April 21 to July 15, and in 1933 from April 14 to July 9. This long period was due in part to the fact that the larvae going into hibernation in the fall were of different ages, but to a greater extent to their uneven rate of growth. Although the period of emergence of the spring brood is extended there was a peak emergence at a date around which most of the brood appeared. This peak in the laboratorv occurred about May 15 in 1932 and May 12 in 1933 (table 1). showed that the peak of s
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