21 



has induced tlie passage of proliibitive import laws in most of tlie vine- 

 growing regions of tlie world, wliicli seriously liamper all private inter- 

 change of plant varieties. The water hyacinth that has stopped up 

 the rivers of Florida, making navigation almost imi)ossibley was an 

 introduction of an apparently harmless ornamental plant. The briar 

 rose since its introduction into Hawaii has become a most troublesome 

 plant and the most serious weed of the Tropics; it is a species of the 

 yellow-flowered Lantana^ so ornamental a house plant in Europe. The 

 I)rickly pear (OpiinUa ficiis-indica), highly i^rized as a fruit in Sicily, 

 has proved a veritable curse in South Africa, causing, according to 

 reliable accounts,* over a million dollars' loss annually. According to 

 Halsted,f in his Preliminary List of the Yv'eeds of Iowa, 18 out of 28 of the 

 worst annuals, 3 out of the 6 worst biennials, and 7 out of the 17 worst 

 perennials are foreign introductions. The Eussian thistle introduced 

 with flaxseed into Bonhomme County, S. Dak., in 1873-74, is now 

 a more or less troublesome weed over parts of 35,000 square miles of 

 farming land.| 



The fact that it is extremely difficult to foresee that a newly introduced 

 plant will become a troublesome pest does not excuse the introduction 

 of any plant whose propensities are already known. Such a step will not 

 readily be excused by the i)ractical farmer, who is constantly reminded 

 of its disastrous results. The English sparrow has proved a serious 

 nuisance wherever it has been introduced, and the English hare in 

 Australia is a veritable curse. 



In a recent bulletin § by Dr. L. O. Howard, of the Entomological 

 Division, the dangerous insects liable to be introduced into the United 

 States from Mexico and Japan are described, and after such a survey 

 nothing but gross carelessness would permit the introduction of such 

 insects from these quarters. 



The gypsy moth (PortJietria disj>ar)j brought into l!^ew England with 

 the idea of breeding up a new race of hardy silkworms at a time when 

 the pebrine disease threatened to destroy the silk industry in France, 

 although combated systematically almost since its first introduction, 

 has cost over $775,000 in State appropriations, to say nothing of the 

 losses which its ravages have caused. 1| 



It is desirable that such surveys be made, and the foreign diseases, 

 both fungous and insect in nature, be called to the attention of those 

 interested in introduction work. A knowledge of the areas infested 

 with insects or fungous diseases would enable special quarantine regu- 

 lations to be passed against those regions, such as have been adopted, 



* Wallace, Eobert. Farming Industries of Cape Colony. London, 1896, p. 90. 



t Halsted, B. D. Bull. Bot. Dept. State Agricultural College, Ames, Iowa, 1888, p. 48. 



t Dewey, L. H. Bull. 15, Div. Bot. U. S. Dept. of Agriculture, 1894. 



§ Some Mexican and Japanese Injurious Insects liable to be Introduced into tlie 

 United States. Bull, No. 4, Technical Series, Division of Entomology, U. S. Depart- 

 ment of Agriculture, 1896. 



II Howard, L. O. The Gypsy Moth in America. Bull. 11, new series, Division of 

 Entomology, U. S. Department of Agriculture, 1897. 



