FUNGOID PESTS OF CULTIVATED PLANTS. 101 



There is a profuse mycelium, and sometimes nothing more, from 

 which arise short erect fertile branches, of a rather thick club -like shape, 

 which are soon divided by transverse partitions into cells ; each of these cells 

 becomes a conidium and acquires a roundish or elliptical shape, and then 

 falls away from its fellows. When quite mature they are capable of 

 germination (30-40 x 15-20 /a). 



The healthy action of the leaves is obstructed, and they soon acquire a 

 sickly appearance, and the stems are apt to rot off at the base. 



The only application which has proved effectual is that of " flowers 

 of sulphur," as in this case the fungus is an epiphyte, and is open to 

 similar treatment to that for the Vine mildew. 



Said to be common throughout the world. 



Sacc. Syll. iv. 189. 



Cucumber and Melon Rot Mould. 

 Plasmopara cubcnsis (B. & C). 



This rot mould was first discovered in Cuba, whence it afterwards 

 spread, until it was found on leaves of Gucurbita and Cucumis in Japan. 

 More recently it became known in the United States, and afterwards 

 in England. 



It forms a delicate white mould on the under surface of the leaves. 

 The erect branches are forked on the upper portion, with the ultimate 

 branches straight, and not hooked as in some species. The conidia are 

 oblong-obtuse at the ends (25 //. long). 



It has been recommended to spray the under surface of the leaves 

 with dilute Bordeaux Mixture, taking care that the under surface is 

 reached and wetted. 



Berk, and Curt. Cuban Fungi, No. G46 ; Sacc. Syll. vii. 872 ; Mass. 

 PL Dis. 80 ; Joum. B.E.S. xxviii. 1904, pp. 639, 673. 



Melon Leaf-spot. 

 Scptoria Cucurbitaccarum (Sacc). 



This leaf-spot has now been found in Italy, France, Austria, Portugal, 

 and South America. The sporules are 60-70 xl/i, 



Sacc. Syll. iii. 2860 ; Bull. Soc. Myc. de. Fr. xxi. fasc. 3, p. 163, fig. 1. 



Melon Spot Mould. 

 Cercospora Melonis (Cooke), PL VIII. fig. 129. 



This disease made its first appearance on the leaves of Melons in 

 1896, and since that time it has been even more troublesome with 

 Cucumbers, and may now be looked upon as a constant danger. 



The leaves are spotted sometimes with rather small orbicular spots 

 with a definite margin, and of the usual bleached dirty-white colour. 

 At other times the spots are larger, one inch in diameter, and of a smoky- 

 grey colour. The mould appears on these spots, but hardly distinguish- 

 able to the naked eye — save to slightly darken the centre of the spots. 



The erect threads are few and slender (200 /x long) and of a decided 

 olive colour. The conidia are robust for the genus to which tiny belong, 



