Economic entomology for the farmer Economic entomology for the farmer and the fruit grower, and for use as a text-book in agricultural schools and colleges; economicentomol00smit Year: 1906 rilE IXSECT WORLD. 321 SO as to warm up rapidly, but there is danger in holding too long, because if the plants start under water, as they sometimes do, the crop is ruined. Occasionally, however, it pays to lose a crop in whole or in part, to free the bogs completely of this insect, as they will then remain practically safe for several years in succes- sion. Where water is abundant and the bogs can be read
Economic entomology for the farmer Economic entomology for the farmer and the fruit grower, and for use as a text-book in agricultural schools and colleges; economicentomol00smit Year: 1906 rilE IXSECT WORLD. 321 SO as to warm up rapidly, but there is danger in holding too long, because if the plants start under water, as they sometimes do, the crop is ruined. Occasionally, however, it pays to lose a crop in whole or in part, to free the bogs completely of this insect, as they will then remain practically safe for several years in succes- sion. Where water is abundant and the bogs can be readily reflowed, the practice of the present day is to draw the water early to induce an early hatching of the insects, and as soon as the larv?e generally appear, reflow, leaving on the water at least twenty-four hours. This will not hurt the plants at that period of their growth, and will kill every caterpillar upon the bog. The effect depends largely upon the care with which it has been done and upon the judgment exercised as to the proper time. It should be de- layed until the great ma- Fig. 370. jority of the eggs have hatched, but should not be delayed so as to run the risk of injuring the plants. In the genus Caccecia we have several injurious species, and none more an- noying than C. rosaceana. „ , . ,, ^ . -'_ '^ Rose leaf-roller, Caccecia rosaceana.—Larva, This attacks a great va- pupa, and adult. riety of plants, but it is most troublesome on roses, spinning and folding leaves and buds and so destroying the flowers. These larvae are not easily dealt with, but spraying the plants with pyrethrum or kerosene emul- sion as soon as the first signs of injury are observed will generally serve to keep them down. On a small scale they may be con- trolled by compressing the spun-up leaves and killing the cater- pillar in its home. Some of the species live in communities, making a nest or web, and such is the Caccecia fervidana, the caterpillar of which lives on oak, and spins
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