. Elementary principles of agriculture; a text book for the common schools. Fig. 101. This apple might Iiave been kept soundby spraying. From Cornell University JuniorNaturalist. Insects on the Farm 165 (a) Food, or Internal Poiso7is, are substances whichpoison by being taken into the digestive tract of theinsect. This class includes various arsenical compounds,such as Paris green, London purple, lead of this class are used for insects that chew theirfood, as the leaf-eating forms, unless the use of the poison. Fig. 1U2. Sprayiug in Liie late durmaut renders the plant
. Elementary principles of agriculture; a text book for the common schools. Fig. 101. This apple might Iiave been kept soundby spraying. From Cornell University JuniorNaturalist. Insects on the Farm 165 (a) Food, or Internal Poiso7is, are substances whichpoison by being taken into the digestive tract of theinsect. This class includes various arsenical compounds,such as Paris green, London purple, lead of this class are used for insects that chew theirfood, as the leaf-eating forms, unless the use of the poison. Fig. 1U2. Sprayiug in Liie late durmaut renders the plants dangerous for food, such as cabbage. (b) Contact Poison. Substances that destroy byattacking the body of the insect, such as washes ofcaustic alkalies, oils, etc. They are used for sucking in-sects, , those having beaks, such as the San Jose scale. (c) Fumigation Poisons, Substances which enter thebreathing pores of the insect and cause death by poison-ing or suffocation. Smoke, and the deadly hydrocyanicacid gas, Pyrethrum, or insect powder, and carbonbisulphide, belong to this class.
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectagriculture, bookyear
