February, '17] BECKER: ROUND-HEADED APPLE TREE BORER 67 



Pruning Compound 



A paint by-product, known as Sherwin-Williams' Pruning Com- 

 pound, was tried in the tests. It was thought that this material 

 might be as efficient as white lead, and at the same time would be 

 cheaper. Ninety trees were treated, of which ten were infested, rep- 

 resenting an infestation of 11.1 per cent, and a protection of —3.7 per 

 cent. In other words, these trees were more heavily infested than the 

 checks. Beetles ate through the paint and the material cracked and 

 flaked badly, and it was not considered worthy of a second trial. 



Conclusions: Sherwin-Williams' Pruning Compound offered no 

 protection against the Borers. 



Paper Wrappers, Wooden Tree Veneers, etc. 



Although these were not tested out at Berryville, it might be well 

 to give a few notes regarding their use. In 1911, Hayhurst observed 

 an instance of where a beetle in eating its way out of its pupal cell 

 had eaten right through a tarred felt wrapper which was over the 

 place where it emerged from the tree. 



It has been the author's observation that various paper wrappers 

 are inefficient, either because they rot or else because of the fact that 

 they are torn and made useless by termites or ants. 



It was further observed in the old orchard at Berryville that trees 

 wrapped with newspapers, as a protection against rabbits, almost in- 

 variably harbored under these wrappers a colony of ants. These ants 

 were observed attending a species of pseudococcus, and it is not unlikely 

 that they would establish symbiotic relationship with the Woolly Aphis. 



Wrappers also tend to keep the trunks of the trees cool and moist, 

 and it was observed that the conditions thus established were especially 

 conducive to attacks of Synanthedon pyri, which insect is quite common 

 in the Ozarks. At any rate, Synanthedon seemed to thrive especially 

 well under the paper wrappers. The same objections would perhaps 

 be found with wooden tree veneers. Moreover, if our screening tests 

 would be indicative, this veneer would have to be altered each year 

 to allow for growth of the trees, which would add to the cost of their 

 use as protectors. 



Conclusions : 1. Paper wrappers and tree veneers may be dangerous 

 on account of harboring other insect pests. 



2. The retreatment and readjustment each year would perhaps 

 make the cost out of the question. 



Screening 



The use of 12-mesh screening is so costly that it would have to 

 be very efficient and permanent to begin with, before it could be 



