. Elementary principles of agriculture; a text book for the common schools. seases in plants. Prevention is the onlysafeguard against loss from parasitic fungi. This isaccomplished in four ways: (a) Treating the Seeds with substances that destroythe disease-causing germs, as scab in potatoes, smut inoats and wheat. (b) Using Resistant Varieties. Not all plants areequally subject to the attacks of parasitic fungi. Somevarieties are much less injured than others. (Fig. 86.)Many varieties of cultivated plants owe their value totheir power to resist disease. (c) Sanitation. When crops are subject
. Elementary principles of agriculture; a text book for the common schools. seases in plants. Prevention is the onlysafeguard against loss from parasitic fungi. This isaccomplished in four ways: (a) Treating the Seeds with substances that destroythe disease-causing germs, as scab in potatoes, smut inoats and wheat. (b) Using Resistant Varieties. Not all plants areequally subject to the attacks of parasitic fungi. Somevarieties are much less injured than others. (Fig. 86.)Many varieties of cultivated plants owe their value totheir power to resist disease. (c) Sanitation. When crops are subject to a particu-lar disease, ail the dead parts, trash and litter thatharbor the spores, should be gathered up and burned. (d) By Using Fungicides. Fungi are poisoned by ex-tremely small amounts of copper salts, or sulphur insome cases, while green plants are not affected by smallamounts. Preparations of copper salts in water are,therefore, used to spray plants to protect them fromattacks of fungi. A compound of copper sulphate (blue 152 Elementary Principles of Agriculture. The *brown rot of plums andpeaches leaves mummies on thetrees.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectagriculture, bookyear
