. Bulletin of the Department of Agriculture. Agriculture. UNITED STATES DEPARTMENT OF AGRICULTURE BULLETIN No. 809 ^^ Contribution from the Bureau of Entomology ^^vFv^^ SJ^'^^^U ^- ®- HOWARD, Chief ^^''^U. Washington, D. C. PROFESSIONAL PAPER March 10, 1920 AMERICAN FOULBROOD By G. F. White Sj^ecialist in Insect Diseases CONTENTS Introduction - • Name of the disease Healthy brood at the age at which it dies of American foulbrood Symptoms Etiology Technique Thermal death point of American foulbrood spores Resistance of American foulbrood spores to drying Resistance of American foulbrood sp
. Bulletin of the Department of Agriculture. Agriculture. UNITED STATES DEPARTMENT OF AGRICULTURE BULLETIN No. 809 ^^ Contribution from the Bureau of Entomology ^^vFv^^ SJ^'^^^U ^- ®- HOWARD, Chief ^^''^U. Washington, D. C. PROFESSIONAL PAPER March 10, 1920 AMERICAN FOULBROOD By G. F. White Sj^ecialist in Insect Diseases CONTENTS Introduction - • Name of the disease Healthy brood at the age at which it dies of American foulbrood Symptoms Etiology Technique Thermal death point of American foulbrood spores Resistance of American foulbrood spores to drying Resistance of American foulbrood spores to direct sunlight Page 1 2 Resistance of American foulbrood spores to ferment ation 31 Resistance of American foulbrood spores to chemical disinfectants 31 Effect of drugs on American foulbrood 32 Modes of transmission 34 Diagnosis 36 Prognosis 38 Summary and conclusions 39 Literature cited 42 Explanation of plates 45 INTRODUCTION American foulbrood is an infectious disease of the brood of bees caused by Bacillus larvae. The disease is characterized by a decided ropiness of the decaying brood and a peculiar foul odor. It is very widely distributed, is readily recognized, and is of much economic importance. Its existence has been known for a long time, and bee- keepers have established many facts concerning it through observa- tions made while practicing their profession. While there is a con- sensus of opinion among beekeepers on certain points regarding the disorder, there are others on which a diversity of views has existed and still others about which almost nothing of a definite nature has been known. Former work was directed primarily toward the determination of the cause of the disease. Among the problems considered in the present studies are: The resistance of Bacillus larvae to heat, drying, sunlight, fermentation, and disinfectants; the effect of the disease on the colony and on the apiary; and the transmission, diagnosis, and prognosis of the disease. Direct
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