Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . black rot fungus usually first appears on theleaves early in summer in the shape of small, sharplydefined reddish-brown spots, having yellowish centers,and dark brown or blackish borders, with numerousminute black pustules scattered over the surface. Ashort time afterward—generally about a fortnight—theattack upon the fruit becomes noticeable. According to Professor F. D. Chester, who hasstudied tins disease in Delaware, ^^the first appearanceof rot upon th
Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . black rot fungus usually first appears on theleaves early in summer in the shape of small, sharplydefined reddish-brown spots, having yellowish centers,and dark brown or blackish borders, with numerousminute black pustules scattered over the surface. Ashort time afterward—generally about a fortnight—theattack upon the fruit becomes noticeable. According to Professor F. D. Chester, who hasstudied tins disease in Delaware, ^^the first appearanceof rot upon the berry shows itself as a light brown spot,caused by the decay of the underlying pulp, this spotincreasing in size so as to involve the entire with this change, the parts first affectedturn black and become covered with minute black pus-tules. Finally the entire berry dries and shrivels, theskin crumpling into angular folds. The entire berry is,at this stage, profusely and uniformly covered with thepustules. If a thin section be made through a rottingberry, the microscope will reveal the presence of minute 79. 80 FrJyGI AisD PUJSGICIDES threads growing into and between the cells. Thesethreads which form the vegetating portion of the fun-gus, technically mycelium, are in diameter only aboutone-sixth that of a single fiber of cotton wool. It is thegrowth of these threads through the tissues of the berrywhich causes the decay and shrivelinof, externally mani-fest as black rot. Microscopic Characters.—At points beneaththe cuticle the mycelium collects into little knots, whichafterwards develop into the black jnistules seen u2:)on the surface. These pus-tules are globular tliick-w^alled sacs or concepta-cles, technically pycnidia,which at maturity are filledwith elliptical spores, FIG. 38. BIT OF SKIN SHOWING PUS- ^Hown as stylospores. The TULEs, AviTH EscAPixG COILED stylosporcs comuiouly es- MAssEs OF SPORES. iiAGxiFiED. ^.^^^ through au apcrturc or pore i
Size: 2217px × 1127px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectpathoge, bookyear1896
