RUST OF THE ORANGE REMEDIES. . 119 



gave about the same results as 66 per cent, kerosene emulsions. The 

 Mites were readily killed, but their eggs for the most part survived. 



Carbolic acid is highly poisonous to plants, and must be used in 

 small doses. Three or four fluid ounces of crude acid dissolved in one 

 gallon of strong soap solution make as strong a wash as it is safe to 

 apply. Although even cheaper than kerosene, it is not a more effective 

 remedy, and, owing to the greater danger attending its use, it cannot 

 be recommended in preference to the latter. 



A strong carbolic or creosote soap can be purchased at a reasonable 

 price, and will prove very useful to orange-growers, as it is not only a 

 powerful insecticide, but also a remedy for " die-back," and possibly also 

 for " foot-rot," or any disease of the plant of fungoid origin. 



Potash. Very strong lye is required to kill the Mites, and their eggs 

 are not destroyed except by solutions sufficiently caustic to burn the 

 leaves and bark. 



The different commercial brands of concentrated lye and caustic pot- 

 ash vary greatly in purity and strength. The potash used in the fol- 

 lowing experiments was a superior article, put up in 1-pound balls, 

 coated with rosin : 



(1.) Solution : 4 pounds (48 ounces) potash to 1 gallon water. Leaves 

 dipped in this solution were badly burned, and, together with them, the 

 Mites and eggs were entirely destroyed. 



(2.) Solution : 2 pounds (24 ounces) potash to 1 gallon water. Leaves 

 charred. Mites and eggs destroyed. 



(3.) Solution : 1 pound (12 ounces) potash to 1 gallon water. Mites 

 nearly all killed. A single living adult seen. Molting Mites and eggs 

 not all killed. Leaves devitalized, but not charred. 



(4.) Solution: 8 ounces potash to 1 gallon. Adult Mites nearly all 

 killed. One half-grown Mite seen crawling about among crystals of 

 potash. Molting Mites and eggs not killed. 



(5.) Solution : 6 ounces potash to 1 gallon. Adult Mites killed. Sev- 

 eral recently molted Mites seen crawling on second day. Molting Mites 

 not killed. Eggs uninjured. 



(6.) Solution : 4 ounces potash to 1 gallon. Many adult Mites killed ; 

 some alive. Numerous young Mites alive on second day. Molting 

 mites and eggs uninjured. 



(7.) Solution : 3 ounces potash to 1 gallon. Same results as No. 6. 



Solutions of 1 pound to the gallon have been used upon orange trees, 

 and although all the leaves and portions of the bark were destroyed, 

 they recovered rapidly from the effects of the application. Such heroic 

 treatment for insect pests is, however, unnecessary and unadvisable. 



Pyrethrum. Applied in fine powder, this insecticide visibly affected 

 the adult Mites and caused them to erect themselves frequently upon 

 their anal prolegs. The free Mites left the leaves in a few hours, but it 

 is doubtful if many of them were killed. The molting Mites and eggs 

 remained uninjured. Continued exposure to contact with the strong 



