204 INSECTS AFFECTING THE ORANGE. 



TABLE 3. LYE SOLUTIONS. 



The following is a synopsis of experiments with potash and soda in caustic solutions : 



Experiments with potash. Experiment No. 90. Solution, 1| pounds potash to 1 gallon 

 water. Applied in fine spray to two thrifty young trees, about four years old. Leaves 

 and tender shoots wilted visibly and changed color during the application, showing, 

 a few minutes later, spots of brown. Two days after the application all the leaves 

 were dead and dried up as if by fire, and remained adhering to the branches. Young 

 growth entirely killed and pitted with holes. Three weeks later all branches under 

 one inch in diameter were found to be entirely killed, the bark of larger branches 

 partly destroyed, the bark of trunk blackened and hardened, but not destroyed. Upon 

 the latter buds had begun to appear. Upon those portions of the tree where the bark 

 was entirely destroyed the insects themselves were destroyed, but one-tenth of the 

 scales upon the dead bark contained living eggs. Where the. bark was^not entirely 

 destroyed half of the Coccids and more than half of their eggs escaped. The tops of 

 both trees were killed and their shape and symmetry ruined. A 40 per cent, kerosene 

 emulsion would have been as effective in destroying the Scale-insect, and would have 

 had no appreciable effect on the tree. A 67 per cent, emulsion, which would have 

 exterminated the insects, would have partially defoliated the most thickly infested 

 branches, without affecting the vigorous portions of the tree. 



Experiment No. 91. Solution, 1 pound potash to 1 gallon water. Applied to two 

 small trees very badly infested with Scale-insects. Owing to the enfeebled condition 

 of the trees, the effect of the lye was as severe as in the preceding experiment. Five 

 weeks later one of the trees was recovering, the other dying, and Scale-insects in both 

 cases increasing. 



Expei'iment No. 94. Solution, two-thirds pound potash to 1 gallon water. Applied 

 to several young trees. Nearly all the leaves dropped and many branches killed. 



Experiment No. 92. Solution, one-half pound potash to 1 gallon water. Applied to 

 two small trees badly infested with Long Scale. Both trees badly, one completely, 

 defoliated. Tender bark and smaller branches killed. Four or five weeks later the 

 trees were recovering, but young brood of Scale-insect had thickly coated all the 

 living branches. 



Experiment No. 95. Solution, four-tenths pound potash to 1 gallon water. Applied 

 to a tree of medium size and in good condition. Great injury to foliage and tender 

 bark. One month later the trees were recovering, but Scale-insect increasing. 



Experiment No. 93. Solution, three-tenths pound potash to one gallon water. De- 

 vitalized branches completely defoliated ; other portions less severely affected. Bark 

 blackened and hardened. One month later trees recovering ; Scale-insect not dimin- 

 dimiuished in numbers. 



Experiment No. 96. Solution, one-fourth pound potash to 1 gallon water. Applied 

 to a vigorous tree. Tree not severely defoliated. Four weeks later Scale-insect in- 

 creasing. 



Experiment No. 86. Solution, one-sixth pound potash to 1 gallon water. Applied to 

 a tree rather badly infested, but still vigorous. Tree slightly defoliated. Scale- 

 insect not checked and no eggs killed. 



Experiments with soda lye. The strongest application of soda lye, two-thirds pound to 

 1 gallon water, was not more severe in its effects upon the tree than one-half this amount 

 of potash applied in Experiment No. 93. The bark was blackened, but not destroyed, 

 and the tree was severely defoliated. The application had no permanent effect in 

 removing the Scale-insects, but these were afterwards destroyed by an application of 

 kerosene emulsion, and the tree in consequence fully recovered its vigor. The remain- 

 ing experiments with soda lye 1 pound to 2, 1 pound to 2i, and 1 pound to 3 gallons 

 of water, respectively (Nos. 43, 44, and 45) failed to check the increase of the Scale- 

 insect. One year later these trees had lost instead of adding to their growth, and ap- 

 peared to be in dying condition, the continued presence of the insects having prevented 

 a recovery from the effects of the lye. The Scale-insects were subsequently removed 

 by applications of kerosene, and the trees began to improve rapidly. 



