Fumigation investigations in California . draw sap from thetree, even thoughthey are very mi-nute, the treesvitality is greatlyreduced. This ef-fect is very markedin the attack- ofthe red and purplescales. Both ofthese species causemuch destruction,yet the writer is ofthe opinion that thered scale will de-stroy a citrus treein less time thanwill the purple Fig. 6.—Orange tree almost destroyed by red scale. (Original.) qpqIp oil nthpr far- tors being equal. Trees have been noticed from two to three yearsafter planting which had been killed by the red scale. Largeorchard trees are frequently des
Fumigation investigations in California . draw sap from thetree, even thoughthey are very mi-nute, the treesvitality is greatlyreduced. This ef-fect is very markedin the attack- ofthe red and purplescales. Both ofthese species causemuch destruction,yet the writer is ofthe opinion that thered scale will de-stroy a citrus treein less time thanwill the purple Fig. 6.—Orange tree almost destroyed by red scale. (Original.) qpqIp oil nthpr far- tors being equal. Trees have been noticed from two to three yearsafter planting which had been killed by the red scale. Largeorchard trees are frequently destroyed by the pest (fig. 6), while itis a very common sight in regions of severe infestation to see largebranches killed back to the trunk. Although no trees have evercome to the writers attention which were completely killed by thepurple scale, severe infestations result in the destruction of manybranches (fig. 7), and cause such a drain on the tree that the produc-tion of fruit is greatly decreased. Moreover, the purple scale spread-. INJURY RESULTING TO SCALE [NFESTED TREES. 15 to the fruit, as docs also the red scale, resulting in expense for thecleaning of fruit in- rendering it of a lower grade and, in extremecases, entirely valueless. The black scale, although a much larger insect than either the redscale or purple scale, appears to have, generally, little effect on thevitality of the tree. Trees severely infested with the black scale mayappear as healthy as neighboring trees which are clean. Branchesare seldom if ever destroyed by its attacks alone. The commercial importance of the Mack scale arises largely fromits habit of secreting honeydew, which spreads over the leaves, fruit,
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectfumigation, bookyear1
