140 ANNUAL, REPORT OF THE Off. Doc. 



when used at the proper strength. Unfortunately, the manufac- 

 turers and agents are claiming that these preparations can be used 

 •one part of the oil to twenty parts of water, when the trees are 

 dormant, to kill the San Jos^ scale, when our experiments have 

 proven that the right proportion for proper results must be one 

 part of the oil to twelve of water. 



Our experiments with cut worms have proven that they can be 

 poisoned with poison bran mash, and we have published extensively 

 in our Bulletins upon this subject. (Vol. III., pp. 356 and 367-369.) 



As most of the results of our original investigations and experi- 

 ments have been published in our Monthly Bulletins, or will be so 

 published, it is not necessary to give them in detail here, but cite 

 from such references as follows: "Preliminary Keport of Fall and 

 Winter Experiments with Commercial Insecticides," January Bul- 

 letin, pp. 272 to 274; ''Experiments with Homemade Insecticides for 

 San Jos6 Scale," March Bulletin, pages 335 to 341; "Tests of Com- 

 mercial Insecticides," pages 342 to 344, March Bulletin; "Experi- 

 ments with Cutworms on Strawberry Plants," April Bulletin, pages 

 367 to 369; "Experiments with the Asparagus Beetle," May Bulletin, 

 pages 6 to 9; "Summer Experiments for Scale Insects," June Bulle- 

 tin, pages 45 to 48; "Summer Experiments for the Oyster-shell 

 Scale," July Bulletin, pages 83 to 84; "Summer Treatment of Scale 

 Insects," Bulletin for July, pages 84 to 88; "Economic Features of 

 the Serpents of Pennsylvania," August and September Bulletins, 

 and "San Jos6 Scale Experiments," November Bulletin, 1906. 



We are continuing investigations along those features of insect 

 life that are not well known, and making a special study of parasites 

 and larger enemies ol insect pests. Among our investigations now 

 going forward, and which we are not ready to publish in detail, 

 are the following: 



"A Study of the Enemies of the Chestnut," "The Enemies of the 

 Locust Tree," "The Insect Pests of Hay and Forage Plants," "Scale 

 Insects and Other Fruit Pests," "Insects attacking Weeds," "The 

 Turtles and Lizards of Pennsylvania," and "Pennsylvanian Amphib- 

 ians." 



The subject of insects injurious to weeds is one of direct import- 

 ance in destroying certain weed pests, and may become of great 

 importance otherwise, as we know that many of these pests, are 

 able to transfer their attacks from weeds to cultivated crops, and 

 thus at once become very destructive. This means that if such 

 pests be left to multiply upon weeds, they are liable to make this 

 manifest by outbreaks upon cultivated plants, and as a consequence 

 the best means of holding them in check is to practice such clean 

 farming as to destroy all weeds they inhabit. Specifically, among 

 such pests are the stalk borers, which feed in the stems of many 

 weeds, but also in many cultivated plants, especially tomato and 

 potato, and also the plant lice, which attack the roots of many 

 kinds of weeds, but also may be very injurious to corn in the spring 

 of the year. 



Experiments are being continued to discover more simple reme- 

 dies for the older and better known insects, to test new 

 materials as they are recommended in certain parts of the 

 earth from time to time, and especially to give fair tests to the 

 commercial insecticides as they appear on the market with adver- 

 tised but too often misleading recommendations of their virtues. 



