SPRAYING FOR THE CITRUS MEALY BUG 249 



In our work the powders were not effective at all and could not be 

 compared to the work of some of the wet sprays. Should they kill through 

 bodily contact, it would be extremely hard to reach the mealy bugs hiding under 

 the bark and smut, or those within the navels of the orange fruit. In badly 

 infested orchards, a great deal of honey-dew is deposited upon the foliage. 

 Upon this honey-dew, the smut sometimes grows to be 1-32 to yi of an inch 

 thick. Where it cracks, mealy bugs enter and hide themselves beneath this 

 protecting coat. A powder cannot reach them here and great numbers are 

 so overlooked. It was therefore necessary to find a mixture which would 

 remove this smut and expose the pests to the direct mercy of the liquid spray. 



KEROSENE. 



A test was made on one tree with pure kerosene. The tree was a four- 

 year-old and naturally rather small. It was very badly infested with egg- 

 masses, larva, and adult female mealy bugs. Fearing serious results to the 

 tree, only IJ/2 gallons were applied with the small hand spray pump. The 

 mealy bugs were killed instantly as soon as the kerosene came in contact 

 with their bodies. The wax on the bodies and egg masses was immediately 

 dissolved allowing the oil to penetrate into all parts of the insect bodies. 

 In no case did an insect crawl or move after the spray had touched it. 

 Most of the bodies turned brown or red, and after a day began to shrivel up. 



The smut was also removed from the leaves and fruit of the tree, so 

 that a day after the application the tree looked much fresher and brighter 

 than did any of its neighbors. 



This work indeed looked marvellous, because nothing had been tried 

 which seemed to instantly kill any number of mealy bugs at any one time, 

 and this being also the first experiment tried in this investigation. The 

 belief was that the tree would be defoliated and the buds killed by the pure 

 kerosene, but after one month, not a leaf was dropped and no ill effects to 

 the tree were noticed. Because of the expense and the probable injury which 

 might occur under different circum.stances, this spray gave way to a more 

 economical spray and one which appears to be very effective without the 

 least sign of injury to the most delicate foliage and buds. I refer to the 

 Carbolic Acid Emulsion which is discussed at the end. 



It is interesting to note that a 25 per cent mechanical mixture of kerosene 

 and water applied to this same tree and to other trees a month later caused 

 a great dropping of leaves and a decided yellowing of the foliage. 



A 25% MECHANICAL MIXTURE OE KEROSENE AND WATER. 



Following along the line of the above experiments with pure kerosene, 

 a mechanical mixture of kerosene and water was tried. The mixture giving 

 the best results was a 25'/' mi.xture. To keep it thoroughly agitated it was 

 applied with a power pump at a pressure of 200 pounds, and mechanically 

 agitated all of the time. Some twenty trees were sprayed with not at all 

 satisfactory results. The leaves were dropped and those which remained 

 turned to a sickly yellow color. The killing power of the spray was very 

 poor — the water caused the oil to gather in globules as soon as it hit the 



