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, g fi_n ' £^; ? Q,}fig • q6� <br /> ,, <br /> y g <br /> { I } gas J' )�p� � � � Y <br /> 1 <br /> Pat,r � <br /> important manpower£ and economic Mite distribution along the length of an <br /> t. <br /> consideration. Ideally, we would like to automated house appears to be uniform. <br /> spend the least amount of time possible on We think this may be due to mites hitch <br /> mite monitoring, and at the same time <br /> hiking on collection belts or in feed. <br /> have reliable information for decision `% Differences occur in distribution between <br /> making. One sampling method that rows. Average hen infestation (number of <br /> minimizes the number of birds to be mites per hen) is positively related to the <br /> sampled is the Sequential Sampling number of hens found with mites. <br /> 77 <br /> -7 77�„ a t In an automated house every row should <br /> The sequential sampling system not only be monitored for mites. Monitoring <br /> considers how many positive birds are � probably can be done at either end of the." <br /> discovered, but also when they were A, house. A threshold for deciding to spray" <br /> discovered (early in the sample or late in }w can be based upon the number of birds <br /> the sample). For instance the decision to with mites. There are several statistical <br /> treat threshold (some predetermined sampling schemes that give equivalent <br /> threshold the decision maker sets) may be amounts of reliability. Some sampling <br /> reached early in sampling if the majority schemes require larger samples than; ' <br /> of the birds evaluated are positive. Ifothers, and some are more complicated.. <br /> however, in the early part of the sample than others. <br /> few or no birds were positive, but man <br /> are positive in the end of the sample, the The availability of new more efficient` <br /> threshold would still be reached (a ;;' miticides will be very limited in the future.. <br /> decision to treat would be made), but not Resistance and cost of application are of= <br /> until several more birds had been primary concern. Effective chemical' <br /> evaluated. 4 }, :;, . , control will depend upon knowing when to <br /> spray and when not to. Spraying too often' <br /> Whatever sampling method is used, may lead to resistance. Waiting until <br /> knowing when the mite population is heavy populations build leads to <br /> #V changing requires routine monitoring. incomplete control and more frequen <br /> 3 <br /> Deciding on a pre-established threshold applications. <br /> for action will offer better overall control ., <br /> x than waiting for mites to appear on the For some farms, the amount of money <br /> zs eggs or waiting until workers complain spent for mite control, easily justifies <br /> allocating time for ranch personnel to <br /> monitor mite populations. If the results <br /> Summary � � ..� r� are utilized in making control decisions, <br /> ., r <br /> control costs can be reduced and resistant- <br /> Mites have a relatively short reproductive populations may be avoided. <br /> cycle, about one week. Because part of <br /> their life cycle can survive off the chicken Douglas R. Kuney <br /> for several weeks, complete eradication is ' Area Poultry Farm Advisor <br /> difficult without treatingthe entire house A4, <br /> �' <br /> and equipmenteg�$ <br /> yw - <br /> s,� <br /> 4 <br />