NEWS
Use bats in your stables to fight AHS midges
By now , if you want a fighting chance of preventing your horses from contracting , and very possibly dying of , African Horse Sickness ( AHS ), your inoculation programme should be complete . But there ' s something else that you can do in your stable yard that might lower the number of carrier midges of the virus and improve the odds against infection , and that is to install a bat box and encourage bats into your environment . The AHS virus is spread by a tiny midge named Culicoides imicola that is active in the early morning from around dawn and late afternoon towards sunset . Bats , on the other hand , feed from early evening to early morning . Insect-eating bats consume vast number of
... and fight bluetongue in sheep , too
insects nightly , mostly locating them by their powerful sonar , which operates in the same way that an underwater sonar is used in a fish-finder , for example . In a process called echolocating , the device ( or bat ) issues a sonar pulse . When this pulse encounters an object in its path , for
MAILBAG
From page 7 plastic lining are leaking , but on the other hand the rate of water loss seems very great . Is there a formula one can use to calculate evaporation and what are the factors involved , eg temperature , relative humidity ? The formulae I have found on the internet are unduly complicated for my unmathematical brain . AllIwantisa example a school of fish or , in the case of a bat an insect , it reverberates back to the transmitter which , sensing the direction it came from and the time it took from transmission to return , can determine both the position of and the distance of the school or insect .
thumbsuck figure to confirm my conviction of undue evaporation , rather than the dam has sprung a leak . In another part of the garden I have a koi pond and , while it also drops in level in hot weather , it doesn ' t seem to drop anything like as fast as my grey water holding dam . I have discussed this issue with friends who have pools in Johannesburg and Pretoria
In this way , fishermen are able to target where to fish and at what depth , and bats , by making instantaneous calculations , can alter their flight paths to intercept their prey . Larger species of bats have been measured to have lower-frequency sonars which are only capable of locating
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and anecdotally it would seem that the evaporation of water this spring was very great indeed . Parched East Rand Any reader have an answer to this question ? Meanwhile , Parched , have a look at our article on grey water in this editon . ~ Editor
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