G2 



The very fact that we always find plenty of scale where we find the parasites, 

 at once proves that the introduced friend is not up to its work in its native 

 home. 



The parasite entomologist says that every insect pest has its effective parasite- 

 If we look closely into the question we see the fallacy of the argument. The 

 exact homes of many of the most destructive cosmopolitan pests are well 

 known, and have been known for many years. Take, for example, the 

 Colorado Beetle or Potato Bug (Dorypliora decemUAfata),wtih its soft unpro- 

 tected larva; the Hessian Fly (Oecidomi/ia destructor}; the Chinch Bug 

 (Blissus leucopteris] ; the Vine Louse ( Phylloxera vastatrix) ; the Cotton Boll 

 Weevil (Anthonomus grandis) ; and scores of just as serious insect pests ; yet 

 none of the parasite workers have ever claimed to know their effective 

 parasite. The artificial conditions of the growth of cultivated plants, and 

 fruit-trees in particular, where they are grafted, budded, and then pruned 

 year after year of the woody growth of nature, and the plant tissue that 

 would form this wood diverted into fruit buds and then into great masses of 

 soft tissue surrounding the seeds which we know as fruit, so alter the consti- 

 tution of the tree that it is not able to resist the attacks of insects, fungi, and 

 bacterial dissases in the same way that the robust seedling growing under 

 natural conditions would. This is undoubtedly one of the reasons why 

 insects are greater pests under intense cultivation. 



There is another great factor in the increase of insect pests, that under 

 their natural surroundings were perfectly harmless to cultivated plants and 

 crops ; we cut down and burn up the forests and plough up the grass lands, 

 and thus destroy the food supplies of the insects that existed there. Many 

 of the more delicate perish, while the more robust, or those that are fortunate 

 enough to find plants allied to those destroyed in the newly-planted trees 

 or field crops suitable for food, turn their attention to the cultivated things, 

 and adapting themselves to the altered conditions and with a bountiful 

 supply of food, they often increase to such swarms as to prove the very worst 

 kind of pest. 



We come across many examples of this in the study of economic ento- 

 mology, arid it is curious to note that they are often not infested with 

 parasites, or that the parasites do not increase in proportion. 



We have an example of this in the increase and the wonderful spread of the 

 American cotton-boll weevil (Anthonomus grandis) over the great cotton belt 

 of the United States. Originally a native of Mexico, it was described from 

 specimens collected near Vera Cruz in 1843, and was known as a pest to- 

 cotton in 1856. In 1893 it had spread pretty well all over Texas ; has 

 since moved on over a very large area in Louisiana ; and, in spite of all pre- 

 cautions, it is working its way northward, following up the fields of cotton. 

 The State and Federal entomologists are working at and investigating every 

 detail in the life history of this pest. Last January (1908) the United 

 States Department issued a Bulletin, entitled "Studies of Parasites of the 

 Cotton-boll Weevil," by W. Dwight Pierce (Special Field Agent). In this 

 very interesting report twelve micro-hymenoptera, all small wasps, and 

 internal parasites, are recorded as having bred from the larvre of the boll 

 weevil ; but several are doubtful, and only four of them have been obtained 

 in considerable numbers ; two mites and two beetles are also placed on the 

 list. Now the genus Anthonomus, to which the boll weevil belongs, 

 contains a great number of different species ; and the field agent is now 

 studying the known parasites of all the different species, in the hope of 

 getting efficient parasites among them. In Professor Hunter's bulletin, 

 issued in 1905, he points out that though there appears to be very little 



