. Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . 6 PUXGI AND FUXGICIDES downy mildew wnlcli causes the well-known rot of theIrish potato. It is now believed that this disease doesmuch less damage in America than has been commonlysupposed, the injury attributed to it being often due toother fungi, but it is sometimes destructive, and its life-history has been carefully studied. The first indication of the presence of the downymildew in the potato field usually is the appearance of. FIG. 3. DISEASED POTAT
. Fungi and fungicides; a practical manual, concerning the fungous diseases of cultivated plants and the means of preventing their ravages . 6 PUXGI AND FUXGICIDES downy mildew wnlcli causes the well-known rot of theIrish potato. It is now believed that this disease doesmuch less damage in America than has been commonlysupposed, the injury attributed to it being often due toother fungi, but it is sometimes destructive, and its life-history has been carefully studied. The first indication of the presence of the downymildew in the potato field usually is the appearance of. FIG. 3. DISEASED POTATO LEAF. brownish spots upon the leaves. As the disease pro-gresses these spots gradually enlarge, finally involvingthe whole leaf, w^hich turns dark brown or neighboring leaves become affected, and the wholeplant eventually wilts and dies. PARASITIC FUNGI 7 If one looks closely at the under surface of the leafbeneath the brown spots, he will see, in case this fungusis present, a w^hitish velvety mold. By making a thincross-section of the leaf at this point, and putting itunder the microscope, an appearance similar to Fig. 4will be seen. At -the right is one of the long pointedhairs which grow naturally upon the under surface ofthe healthy leaf; next to this toward the left is anotherpeculiar leaf-hair v/ith a club-like tip; and beyond this
Size: 1624px × 1539px
Photo credit: © Reading Room 2020 / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectpathoge, bookyear1896
