102 INSECTS AFFECTING THE ORANGE. 



brood interval will have elapsed and fresh eggs will be deposited. Suc- 

 cessive applications should, therefore, be made at intervals of not less 

 than three and not exceeding six weeks. 



Proper Seasons for applying Remedies. If kerosene emulsions are used 

 trees may be treated for Scale at any time during the growing season. 

 Strong solutions of lye, whale-oil soap, and other applications which 

 are injurious to tender growth do least harm to the trees when dormant. 

 The brood periods of Scale-insects are quite irregular, and breeding is 

 more or less continuous throughout the year. As a rule, however, in 

 Florida new broods begin in March, June, and September, and in these 

 months, or the month succeeding each, the application of insecticides 

 gives the greatest advantage. The period immediately preceding the 

 appearance of each brood is that in which the majority of scales are 

 filled with eggs, upon which many insecticides have little or no effect. 

 The months of February, May, and August, and the winter months 

 from November to January, are, therefore, seasons in which the applica- 

 tion of remedies is likely to prove least effective. 



To apply washes in winter is somewhat hazardous, and exposes the 

 trees to risk of serious injury, by causing them to put forth new growth 

 at a time when there is danger from frost. For in Florida the Orange is 

 never quite dormant even in the coldest winter, and the reaction that 

 follows an application is liable to start the buds unless the weather re- 

 mains uniformly cool. 



When the air is charged with moisture, and the nights are cold, with 

 heavy dews or frost, the evaporation, even of volatile oils, is checked, 

 and they remain too long in contact with the plant. Applications made 

 under such atmospheric conditions sometimes prove very severe, and 

 cause the tree to shed all its leaves, or even kill the branches. 



