448 EXPERIMENT STATION RECOED, [Vol.37 



were effective In controlling fungi but more dangerous to fruit and foliage 

 and more expensive than Bordeaux. Soluble sulphur and atomic sulphur proved 

 effective in controlling apple scab but did too much damage to fruit and foliage 

 to warrant their use in their present form. 



Practically no difference was found in any of the standard brands of arsenate 

 of lead. Two lbs. of arsenate of lead paste or 1.25 lbs. of arsenate of lead 

 powder have been found to be as efficient as larger quantities. 



Spray applied with hollow stream nozzles was found fully as effective as 

 when applied with the solid stream type. More spray injury and waste of 

 material accompanies the use of the latter. 



The results of the work of the last three seasons indicate that while it Is 

 sometimes possible to omit either the fungicide or the insecticide In the first 

 spray, or to omit the first spray altogether without suffering serious loss, it 

 is never safe to do so and is more hazardous to omit the fungicide than the 

 Insecticide. Clean culture was found to be of paramount importance in con- 

 trolling the plum curcullo and apple scab. Power machines are the most satis- 

 factory where the orchard is large enough to warrant their use. though not 

 necessarily more efficient than a good type of hand outfit when the latter is 

 properly used. 



Five years' investigations in apple thinning, E. C. Acchteb ("n'cs^ Virffinia 

 Sta. Dul. 162 (1917), pp. S-56. figs. 9).— This bulletin reports thinning experi- 

 ments carrleii on by the station for the 5-year period 1912 to 1916. During 

 this period 1S7 trees of different ages, growing under different environmental 

 conditions and consisting of the varieties Rome. Baldwin. York Imperial, 

 Delicious, and Ben Davis, were under test. For the most part the experiments 

 were not conducted continuously on the same trees owing to the failure of 

 the trees to set fruit in certain years, hence the results for each season are 

 presented in detail. Owing to the lack of an apple crop In 1913 a thinning 

 experiment with peaches was conducte<l and Is here noted. 



The results from the thinning experiments as a whole indicate that it does 

 not pay to thin in years of light crop production if the trees are vigorous and 

 growing in fertile soil. Where apple trees are bearing from a me<llum to a 

 heavy crop of fruit the removal of a part of this fruit by thinning is a very 

 profitable practice. In all cases where the trees had a gixxl crop thinning 

 Increascil the size and improved the color of the fruit, thus enhancing its 

 market value. The results of the experiments indicate that thinning does not 

 influence subsequent crops nor cause trees naturally biennial in bearing habit 

 to bear a crop each year. . 



Winter varieties of apples may be thinned Just after the June drop, since 

 much of the fruit removed by too early thinning will drop off naturally at the 

 time of the June drop and the remaining apples on the thinned trees may then 

 be thinned too much. In the case of summer or early autumn varieties it is 

 suggested that it will probably pay to delay thinning until the fruit Is large 

 enou.irh to use and then several thinnings should be made as the fruits size up. 

 In most cases the best results were obtaine<l when the fruits were thinned 

 6 to 7 in. apart In the case of old trees bearing good crops 9 to 10 in. apart 

 gave slightly better results. 



One year in one lot of 12 trees the thinned trees returned twice as much 

 net per tree as did the unthlnned trees. Another year the thinned trees gave 

 at least a 75 per cent greater net return per tree. In some cases the increases 

 were not so striking. The cost of thinning ranged from 81 cts. to 43J cts. 

 per tree, depending on size of crop and tree. The author concludes that only 

 a small part. If any, of the cost of thinning should be charginl against the 

 thinned trees, parti; t>ecause the fruit thinned off would have to be removed 



