THE PEACH-TREE BARKHKETLE. 105 



periments 29. 30, and 31 failed lo give ;\ny beneficial results, the 

 cnnilsion being ver}^ poor, as the oil l)ecame partl}^ separated from the 

 jnixture before the latter could be a]jplied. Experiments 32, 33, 34, 

 35, 3(), and 37 gave only negative results, neither killing the beetles in 

 the burrows nor repelling later attacks. In experiment 38 a plat of 

 100 trees was used. Fifty of the trees were very severely cut back and 

 4 or 5 of them, being too weak to recover, died. The other 50 trees 

 were sprayed with lime-sulphur wash. At the end of the season the 

 pruned trees had produced a strong, healthy foliage and the beetles 

 were attacking them but little. The untrinnnod trees were badly 

 attacked and had thrown out a scant, sickly-looking foliage. Experi- 

 ment 39 gave satisfactory results. All of the beetles in the trees at the 

 time of application were killed and no more settled on them until 

 iibout the last of September; then, a few having settled, the trees were 

 whitew^ashed and further injury was stopped. The cost of this treat- 

 ment, as made here, prevents it being practicable for a large orchard 

 unless the amount of material used can be reduced with equally good 

 results for the weaker emulsion. Experiment 40 showed that the 

 beetles attack the trees in which these cut branches were placed with- 

 out settling on the cut branches. Experiments 41, 42, and 43 showed 

 the most practicable, and at this time the most likely remedies. These 

 are the combinations of a whitewash and an oil, the whitewash 

 probabl}' being the main factor in repelling the beetles. The cost of 

 these experiments was 1| cents per tree for each application. The 

 trees in these plats, while not entirely free from further attack 

 during the season, suffered considerably less than surrounding plats 



of trees. 



METHODS OF CONTROL. 



Pending further investigation, the following treatments are sug- 

 gested as being practicable and to a certain degree favorable: 



For trees seriously injured. — Severely trim back the trees and apply 

 barnyard manure or commercial fertilizers; then apply a thick coat 

 of whitewash three times a season, the first api^lication to be made the 

 last week in March, the second application during the second week 

 in July, and the third application about the 1st of October. 



For trees ((pparctitbj hedltliy h\d slightly attacked. — Paint the 

 trees with a thick coat of whitewash three times each season as in the 

 previous treatment, applying it to the trunks and larger limbs. The 

 whitewash applied at the times specified will act as a repellent, the 

 emergence of the beetles being slightly later than the dates given for 

 the different applications. Add one-fourth pound table salt to each 

 })ail of whitewash, thus making the latter more adhesive. All of the 

 dead or nearly dead limbs and trees should be removed and burned as 

 fast as they appear in an orchard, as this will destroy the breeding 

 places. 



