6 Farmers' Bulletin 801. 



LENGTH OF LIFE. 



It is probable that in a poultry house once infested at least four 

 months and probably five will be required before all of the mites 

 will starve if the chickens are removed from the house. In tests 

 made by the writers some mites were still alive after a period of 113 

 days, and since these individuals were collected from an infested house 

 it is not unlikely that they had matured some time previously. The 

 tests indicate that where the mites are supplied with a certain amount 

 of moisture they will live longer than when kept under very dry con- 

 ditions. This may account, in part at least, for the idea that mites 

 are worse in damp and badly ventilated chicken houses. 



HOSTS AND METHODS OF SPREAD. 



Chicken mites do not feed to any great extent upon other hosts 

 when chickens are at hand. They are carried about chiefly by the 

 interchange of poultry and in crates and boxes in which fowls are 

 shipped. No doubt clean premises sometimes are infested by mites 

 carried on the clothing of people going from one chicken yard to 

 another. 



CONTROL. 



Owing to the fact that mites feed during the night and secrete 

 themselves in cracks and crevices during the day, their presence very 

 often is overlooked until a very heavy infestation has developed. 

 In such cases they should be attacked energetically. Al'though not 

 hard to kill, the greatest obstacle is the difficulty of reaching them in 

 their hiding places. Dust baths will not control them, as at most 

 only the few which remain on the chickens during the daytime will be 

 destroyed. 



TREATMENT OF INFESTED CHICKEN HOUSES. 



The first step necessary to destroy the mites is to get rid of the hiding 

 places so far as possible. The roosts should be taken down and all 

 unnecessary boards and boxes removed. In heavily infested houses 

 the mites are to be found in all parts of the building, including the 

 roof. Where they are less numerous the infestations usually are con- 

 fined to the roosts and nests and the walls immediately adjacent. 

 For small coops a hand atomizer will suffice for applying insecticides 

 as sprays, but for larger houses a bucket pump, knapsack sprayer, or 

 barrel pump is desirable. A rather coarse spray should be applied 

 from all angles and thoroughly driven into the cracks. The floor 

 also should be treated, as many mites fall to the floor when the 

 roosts are being removed. 



In tests conducted during the last four years several different 

 materials used as sprays have proved effective against mites. Com- 

 mercial carbolineum which consists essentially of a high-grade 

 anthracene oil has proved very effective. The kilHng power of this 

 substance, which is derived from coal tar, lasts for several months, 

 and mites which may be inclined to come in from other buildings 



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