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Page:Popular Science Monthly Volume 72.djvu/415

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INSECTS INJURIOUS TO AGRICULTURE

established in the north did not succeed. But, on the other hand, colonies installed in the Georgia orchards and other southern states rapidly spread, naturalized themselves, and still fill a useful role in attacking the San Jose scale. However this may be, this importation can never be compared to that of Novius cardinalis. Mr. Marlatt himself states that this insect does not seem to have found in America, up to the present time at least, conditions as favorable to its development as in its native country. Moreover, the time when it was introduced coincided with the period of employment especially of the lime-sulfur-salt wash, and obviously the use of such an efficacious remedy should not be interrupted to allow the ladybird to spread.

Scutellista cyanea.—The success gained by beneficial parasites, properly speaking, is at present rare and less startling than those which the predaceous insects, and particularly ladybirds, have brought about. An especial rank, however, should be given to a Hymenopterous parasite of the family Chalcididæ, Scutellista cyanea Motsch., which is among the most useful of the American importations. It was first described from Ceylon, where it was found attacking parasites of the coffee scale. Then it was found again by Berlese in Italy, where it attacked the wax scale of oranges and other plants.

Howard, with the help of Berlese, tried in 1898 to introduce it into Florida and Louisiana, to combat the wax scale, injurious in that part of the country. This first attempt at acclimatization failed. In the meantime, Lounsbury, State Entomologist at the Cape of Good Hope, drew attention to this parasite as one of the most efficacious enemies of the black scale of the olive. The olive scale is not abundant enough at the Cape to be considered as injurious, and the damage which it does is always less than in America and particularly in California. On this account, and considering Scutellista to be the cause, the State Board of Horticulture of California, always looking for new assistance of this kind, tried to get this parasite. In 1900-01, branches carrying parasitized black scale were sent from the Cape to California. Some parasites were obtained by breeding from these different sendings, but their number was not sufficient to undertake a rearing in the large cage constructed around the tree infested by scales, but, in 1902, numerous colonies were sent into all the districts of the State of California where the black scale was injurious. Since 1903, numerous orchards have been found which have been practically cleaned of the black scale by this parasite. It may be affirmed that this introduction is one of the most fortunate ones for fruit growers in California.[1]

The Struggle in America, by means of Parasites, against the Gipsy


  1. The acclimatization of this insect appears also to have been brought about in Australia, where it was introduced in 1904, and in Hawaii, where it was imported in 1905. Mr. Lafont has lately announced the presence of this insect in France, where he considers it a very efficacious parasite of the black scale.