320 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



It was found during the year that the sugar-cane moth borer also 

 damages rice in Louisiana. It probably has been confused hereto- 

 fore with the rice stalk-borer, which resembles it closely. An in- 

 vestigation of these two j)ests in their relation to the rice crop has 

 been started. 



INSECTS AFFECTING THE HEALTH OF MAN AND DOMESTIC 



ANIMALS. 



ScKEW-woRM AND nLOWFi.iES. — The investigations on this project 

 have been continued in cooperation with' the Bureau of Chemistry 

 and the Texas Agricultural Exi3eriment Station. Extensive experi- 

 ments have been carried out at several points in Texas to find if 

 possible some satisfactory repellent which may be used to keep 

 screw-worms and blowflies off wounds on animals until they have 

 healed. This has required the testing of a great many substances 

 and many repetitions of the tests. Several very promising chemi- 

 cals have been found which are to be given extensive tests under 

 range conditions. Attention has been given to finding a less ex-, 

 pensive and more stable material than chloi'oform for killing screw- 

 worms and wool maggots. 



It has l)een conclusively demonstrated that the use of the fly- 

 trap designed by the bureau, in conjunction with carcass destruc- 

 tion, is a very effective method of reducing screw- worm and wool- 

 maggot troubles in the Southwest. Experiments have been con- 

 tinued to find effective dry baits which can be carried on liorseback 

 in concentrated form for use in flytraps on tlie range. Dried egg is 

 giving excellent satisfaction and is more generally avaihible and 

 more pleasant to handle than dried intestinal mucus, which was 

 introduced by the bureau three years ago. 



AVakble or oRiTD. — Studics of the warble or grub of cattle have 

 been continued along lines similar to those reported upon last year. 

 Considerable attention has been given to further studies of the life 

 history and seasonal history of the northern warble, Tlypoflcrma 

 hovis, in New York. Further steps have been taken to prepare 

 the people of that section for extensive control work. AVhile the full 

 extent of dtimnge from this pest is not generally recognized by the 

 stockmen and dairymen, they all admit that control or eradicative 

 procedure is well warranted. It is believed that such procedure is 

 feasible, as the insect restricts its attack to cattle. It is present in its 

 later larval stages under the hide along the backs of cattle during 

 a few months only of each year, and in this situation it can be de- 

 stroyed with certain treatments, such as the application to the open- 

 ings of iodoform 1 part to petrolatum 5 parts. The principal 

 features in the life and seasonal history of the two species of warbles 

 have been determined with sufficient exactness to make it ])ossible to 

 proceed with tests of control methods on a considerable scale. 



Lice affecting live stock. — Studies of the life histories of the 

 lice, especially goat lice, have been in progress during the winter 

 months, and experiments in cooperation with the Texas Agricultural 

 Experiment Station are under way to determine the best procedure 

 to follow in order to insure complete destruction of all lice by dipping. 



Insecticide studies. — Further tests with the little-known insecti- 

 cide derris have been carried out and the results published. This 



