560 REPORT OF THE COMMISSIONER OF AGRICULTURE. 



ments are required to be positive. The resin compound will penetrate the cottony 

 mass of Icerya as well as, or even better than, soap. Yet its actions are slower, and 

 if not used sufficiently strong, even if all the eggs are destroyed, some of the mother 

 scales will not be killed by it, or if so, only after they have left a few fresh eggs, 

 which will in due time hatch. Such eggs, if few, are brought forth loose, i. e., 

 without the usual protection of cottony exudation, and either drop to the ground 

 or lie free above the destroyed egg-mass and under the dead mother. No doubt, 

 many of tliese eggs never hatch, especially in hot weather. 



It is quite different with eggs which are deposited by females that really survive 

 treatment; the usual cottony mass is exuded, and thus the eggs are protected as 

 usual and hatch always. 



Its action on Red Scale is very promising, either mixed with soap or in simple 

 emulsion, as experiments will show. Experiment 132, i pint of compound to 1 gallon 

 of water, although costing only i cent per gallon of the wash, destroyed a large num- 

 ber of the scales; and a few days after appUcation the covering became loose from 

 the insect, so much so that some of them could be blown off and leave the insects 

 exposed, affording an excellent opportunity for the mites, with which the tree was 

 svearming, and which do not seem to be harmed by the wash. 



A strong application of this emulsion will form a coating over everything on the 

 tree, will exclude the msects from au- for a few days, and will have entirely disap- 

 peared in a week in warm weather, as shown in experiment 134. 



LYE SOLUTION. 



A few experiments were made on hedges of young orange plants. Experiments 

 108-118 wilf show the results. While in every case the plant was more or less in- 

 jured, the insects alone were killed, or part of them, and the contents of egg-sacs 

 were not in the least affected, even with so strong an application that the plant was 

 destroyed entirely. 



BISULPHIDE OF CARBON. 



A few experiments were made in fumigating with this article, but its action is too 

 slow to be of value on large trees. Messrs. Wolfskill and Craw have made several 

 experiments, and on trees of about 8 feet in diameter all the scales were destroyed 

 in twenty-four hours. The trees were greatly benefited by it, as I am informed by 

 these gentlemen. 



KEROSENE EMULSION. 



The cost of this article is too high for general use as a remedy for the Cottony 

 Cusliion-scale. An emulsion of " kerosene 1 gallon, soft soap i gallon, and water 1 

 gallon " (see experiment 41), cost about 24 cents for 2| gallons of the emulsion. This 

 is wholesale price. Tlu-ee pints of this emulsion is required to 1 gallon of water to 

 destroy both the Icerya and its eggs. This would be about 18 cents for 7 gallons of 

 the wash. 



In all the experiments made with this emulsion I have not seen the slightest injury 

 done to the trees, as is the case with some of the soaps if used too strong. 



Made in this way with soap, it penetrates the cottony mass more easily than if 

 emulsified with some other substance. 



Very good results were had with emulsion of petroleum. As this could be bought 

 at froin to 7 cents per gallon in large quantities and combined with soap, it makes 

 a reasonably cheap wash. The orange trees are left in an unsightly condition even 

 for a month or six weeks after application, and it could therefore not be used on 

 maturing fruit; yet if properly tried it may do good work on other scales on de- 

 ciduous trees in the dormant state. 



EXPERIMENTS.* 



I now give in some detail an account of the more instructive of the experiments- 

 made, noting results in each case. 



Experiment 18. Sheep-dip. 



Sheep-dip, 1 pint; water, 15 pints. Applied July 9. On examination, July 16. found 

 but few of the smaller scales killed; contents of egg-sacs not affected. Mr. Coquil- 

 lett reported on other experiments with same mixture. 



* It will be noticed that the numbers of the experiments are not perfectly con- 

 seciitive; but the omitted numbers will be found under the head of the "Red Scale", 

 in the last section of the report. 



