EXPERIMENT STATION BULLETINS. 271 



the leaves and not long after the young larvae appear. These will be found 

 of all sizes through the summer and into the autumn. To fight these 

 insects successfully is a most difficult undertaking. Trapping them under 

 boards at night, and gathering and killing them very early the next morn- 

 ing, before they have dispersed, is a laborious proceeding. Hand picking, 

 and sweeping or brushing them into a vessel containing kerosene oil is still 

 more hard and irksome. We had hopes that we could use the kerosene 

 emulsion or at least the pyrethro-kerosene emulsion successfully in 

 destroying these bugs, but on the old bugs we fail entirely. We have not 

 been able to kill them except we used an emulsion so strong that we also 

 killed the plants. We can kill the eggs and nymphs with either emulsion 

 but not the mature bugs. Pyrethrum either as powder or in the liquid form 

 has no effect on the imago, and so we were not greatly surprised that the 

 pyrethro-kerosene emulsion was not superior to the simple kerosene 

 emulsion. As we have no good remedy for this mature squash bug it is 

 very desirable that one be discovered. 



KEROSENE EMULSION FOR PLANT LICE. 



As yet we have never used kerosene emulsion in vain to kill aphides or 

 plant lice. We believe a good one fifteenth kerosene emulsion thrown on 

 with force, by a good force pump, so as to touch every louse, will always 

 give satisfaction. Hundreds to whom we have recommended this specific 

 for these insects, have reported absolute success, while occasionally a per- 

 son has complained of failure. In the last case we believe that the emul- 

 sion was faulty, or more probably its use was delayed till the leaves had so 

 curled up as to protect the lice, or perhaps the liquid was thrown on so 

 mildly that it failed to strike many of the lice, and so of course would not 

 kill them. It must be remembered that this kills by contact. We wish 

 to urge again the wisdom of an early treatment of plant lice, just before 

 the eggs hatch or just as the young lice come from the eggs. Then the 

 buds are just opening, the leaves are still in the bud, and it is easier and 

 much more economical to spray thoroughly than it is to wait till the 

 foliage is fully out. More than this, each day that we wait takes just so 

 much vigor from the tree, and this in the early spring, when the plant or 

 tree needs all its sap for its growth and development. The plant lice pass 

 the winter as eggs. In the spring the little black eggs, which are usually 

 thick about the buds, hatch just as the buds begin to swell or open. All 

 these spring lice are females and ovo-viviparous, that is, the lice are 

 brought forth alive, so we see no eggs except in the fall, winter, and early 

 , spring. All the females except the autumn ones produce without males, 

 hence the increase is very rapid. It is wise, then, for every gardener and 

 fruitgrower to note what plants suffer from aphides and then in winter 

 note if the eggs are abundant or else in early spring, just as the buds begin 

 to open, examine to see if the young lice are thick on the buds. In case 

 they are, the kerosene emulsion, one fifteenth kerosene, should at once be 

 dashed upon the trees, when the lice will be quickly exterminated. Another 

 advantage of this early treatment is the less likelihood of injury to the 

 foliage. We applied a one'fifteenth soft soap emulsion (No. 1) to plums 

 the first of June. It killed all the aphides but injured the foliage. We con- 

 cluded that it was a case of the "last straw," as the foliage had already been 

 much injured by the lice. From later experiments we think it may have 

 been due to the quality of the soft soap, as already explained. We have a 



