536 DISEASES OF CULTIVATED PLANTS 



the year 1891, which resulted in the destruction of pastures, 

 heather, trees, and practically everything of a vegetable 

 nature that was encountered. According to Theobold this 

 plague was the outcome of * constant war with trap and gun 

 upon the gamekeeper's so-called "vermin."' The Scottish 

 farmers had to suffer for the ignorance of the gamekeepers, 

 who had killed off the natural enemies of the voles namely, 

 the hawks, owls, crows, weasels, polecats, etc. which even in 

 game preservation do more good than harm, as we have seen 

 in the fatal * grouse disease.' 



A still more serious outbreak of voles occurred in Thessaly 

 in 1892, which threatened to destroy the whole corn crop of 

 the district ; but thanks to Professor Loeffler, the voles were 

 exterminated by inoculation on a large scale with his bacilli 

 typhi murians? 



Voles often nibble quite through living roots of beech and 

 other trees. I have seen roots two inches in diameter cut 

 completely through, and it is stated that roots as thick as a 

 man's arm are often similarly treated. 



Theobold, F. V., Agric. Zoology, p. 471 (1899). 



Mice are mischievous little animals that often do a certain 

 amount of damage to trees, the vine being a special 

 favourite. The Field Mouse \Mus sylvaticus) is a terror in 

 the garden, ruining bulbs and clearing out rows of peas, etc. 



When the bark of plants has been injured, the wounded 

 part should be wrapped round with old flannel soaked in 

 puddled loam, when new roots will be formed if the bandage 

 is kept moist. It may be mentioned, although outside the 

 scope of this work, that if a layer of sifted coal ashes about 

 an inch thick is placed over rows of newly sown peas, they 

 are protected from raids by mice. 



Woodpeckers are guilty of injuring trees to a certain 

 extent by making holes in the trunk in which they build 

 their nests. Sound as well as partly decayed trees are used 

 for this purpose, soft-wooded kinds being preferred. 



The Green Woodpecker (Gecinus viridis\ Greater Spotted 

 Woodpecker (Picus major) and Lesser Spotted Woodpecker 

 (Picus medius) are our commonest species. 



On the whole, the good done by these birds in feeding on 

 injurious insects more than compensates for any injury done. 

 The holes made should be filled with cement to prevent the 

 entrance of wet or the spores of fungi. 



