2 BULLETIN 1228, U. S. DEPARTMENT OF AGRICULTURE. 



The tests included a number of materials and methods grouped 

 under the heading "Miscellaneous treatments," besides special 

 studies of various substances applied in the form of paints, dusts, and 

 sprays. Details of these tests are given under appropriate headings. 



In a number of cases substances were tested in small containers, 

 such as jars and vials. Such tests, involving both contact and 

 fumigation action on the mite, were considered so severe that failure' 

 to obtain satisfactory results thereby indicated with certainty that 

 the materials would be inefficient in practical use in chicken houses. 

 Such materials might, therefore, be classed as of no value, without 

 further testing. 



In computing the degree of efficiency, in tests other than in small 

 containers, it was found necessary to use somewhat arbitrary terms. 

 It is next to impossible to make actual counts of the mites alive and 

 dead on a roost or in a nest box, and much more so in a chicken 

 house. The effect of a material can be gauged only by estimating 

 the general mortality from the percentage of living and dead found 

 in the more easily observed places and by observing how rapidly 

 reinfestation occurs in the premises. In the latter case the season of 

 the year should also be taken into account, as the mite reproduces 

 more rapidly under higher temperatures. 



Many materials proved to have no value in the control of mites. 

 Others listed as "inefficient" failed to reduce the mites sufficiently to 

 prevent a speedy reinfestation. In some such cases it appeared that 

 a major percentage of active mites were killed outright, but no 

 effect was exerted on the eggs. Materials to which the term " some- 

 what efficient" is applied were those in which it appeared that 60 to 

 75 per cent of the mites were killed, but the residue was large enough 

 to bring about a speedy reinfestation. " Moderately efficient" 

 materials were those which reduced the infestation greatly and 

 prevented more than a comparatively small subsequent reinfestation. 

 The term " efficient" was reserved for materials which killed all or 

 almost all the mites, and subsequent infestation, if any appeared, was 

 insignificant in proportion to the original. 



These terms apply only to single treatments. In many cases two 

 or more treatments were made in the same premises. While the 

 total mortality was increased thereby, the treatments were not 

 progressively effective, the subsequent ones not equaling the original 

 in effectiveness. Unless otherwise noted, the tests described herein 

 represent single treatments. 



MISCELLANEOUS TREATMENTS. 



FUMIGATION. 



An infested roost was fumigated in a fumigatorium of 360 cubic 

 feet capacity for 6 hours by burning, in sawdust, 8§ ounces of naph- 

 thalene. A number of mites were fumigated in a tight container 

 for 30 hours by burning the same quantity in carbon. Both treat- 

 ments were effective. An infested nest box was treated by burning 

 13 grams of pyrethrum. A chicken house was fumigated by placing 

 in live coals on the floor 58 cubic centimeters of a preparation con- 

 taining 7.5 per cent of borax and a small quantity of pyrethrum. 

 Two chicken houses were fumigated by burning respectively 1 and 2 

 pounds of sulphur for 4 hours. The capacity of the houses used in 



