PESTS OF ORCHARD AND FRUIT GARDEN. 



41 



All species of this genus are suspicious, and we doubt if this is really 

 •so innocent as has generally been supposed. 



It is known in France, Belgium, Germany, and the United States. 

 Sacc. Syll. iii. 3690. 



Strawberry Spot Mould. 

 Bamularia Tulasnci (Sacc), PI. XII. fig. 41. 



This fungus spots the leaves in a very similar manner to the ordinary 

 leaf -spot. They are rather small orbicular white spots with a broad 

 •definite dark-reddish margin, but without any dots. A white mould is 

 seated upon the spots, which produces little bundles of colourless threads, 

 and these develop at their tips cylindrical hyaline conidia which are 

 straight, with one or two cross divisions (30-35 x3-4 jj). What appears 

 to be the same fungus was known here for some years under the name 

 of Cylindrosporium Grevillcanum. The life history of this fungus has 

 been investigated in North America, and hence we know more of it than 

 of most leaf- spots, and that this fungus constitutes the conidia of another 

 fungus, which appears later on and is known as Sphcerella fragarice. 

 For our purpose we may treat them as two separate diseases, with 

 •different manifestations and different treatment. 



The mould is known in Britain, France, Italy, Holland, and North 

 America. 



In this stage it is more likely to submit to treatment by fungicides 

 than in the more mature cr resting condition. 



Sacc. Syll. iv. 988 ; Sacc. F. Ital. t. 1006 ; Mass. PI. Dis. 107. 



Ripening fruits are liable to attack from Oidium Balsami, already 

 •described (ante, vol. xxvii. p. 806). 



Straw t berry-leaf Blight. 

 Sphcerella fragarice (Sacc), PI. XII. fig. 42. 



When a spot first appears on a young leaf it is brownish or reddish, 

 then becomes circular with a dead white centre (3-6 mm.) and broad 

 .purple border. Subsequently conidia are produced as already described 

 (Bamularia Tulasnei), which for some time are produced in succession 

 from the same threads. If these conidia fall on a fresh leaf surface they 

 germinate in a few hours. In the latter part of the season the mycelium 

 becomes compacted into sclerotia, which are capable of germinating and 

 producing a crop of conidia in the spring. 



Perithecia are developed in late autumn, but are not matured until 

 the spring, upon the white centre of old spots. Asci are produced within 

 these perithecia, each containing eight oblong colourless two-celled 

 •sporidia (15x3-4 /u). 



The fungus passes the winter under three forms : (1) as mycelium in 

 the leaves, (2) as sclerotia developed from the mycelium, (3) as ascospores 

 produced in the perithecia. 



The remedies suggested are a solution of sulphide of potassium one 

 ■ounce to eight gallons of water. Also the copper solutions. Burning of 

 .all spotted leaves which may carry the disease over to the spring. 



