Winter Meeting- 259 



"ii 



secticicles are much lighter to handle and can be applied much more 

 rapidly than those which are applied in water. 



]\Iany of our fruit growers have hundreds of acres in orchards 

 and some of them have thousands of acres. .Some of our best fruit 

 lands are on steep hillsides where an enormous amount of power is 

 necessary to haul the heavy liquid spraying mixtures through the 

 orchards. In other cases spraying is done when the ground is soft 

 in spring and hauling heavy loads through the cultivated orchards 

 becom-es very burdensome and also cuts up the ground, leaving it in 

 an undesirable condition. In many cases, on the well drained lands, 

 Avhere surface ponds cannot well be made to hold water, not enough 

 Avater can be had within reasonable distance to enable the grower to 

 use the licjuid spray. It also not infrequently happens that there are 

 not enough teams in the neighborhood to spray these enormous or- 

 chards at the proper time if the heavy liquid sprays are used. 



In a number of orchards where it is not feasible to use the liquid, 

 the fruit growers have for some years been using the fungicides and 

 insecticides in the form of dust. In some cases fairly satisfactory 

 results have been reported from using air-slacked lime as a fungicide 

 and mixing Paris green with it for an insecticide. In other cases a 

 dry copper mixture has been made by dissolving the copper sulphate 

 in water and then using this solution to partially slack the lime, which 

 was allowed to finish the slacking process in the air and thus become 

 dry after the copper sulphate solution was added. 



One serious difficulty has been encountered, however. The lime 

 alone has not enough fungicidal value to fulh- meet the needs of the 

 grower. In adding the copper sulphate by the methods usually em- 

 ployed by the grower its fungicidal value has been partly destroyed, 

 thus leaving the dust less efficacious than the licjuid spray. It must 

 be added, however, that the results obtained have been more satis- 

 factory than was expected at first. Some of the dry Bordeaux mix- 

 tures have proven to have considerable fungicidal value and when 

 Paris green has been used with air-slacked lime as an insecticide 

 results have been fairly satisfactory. 



There is great need of an efficient dry Bordeaux mixture that 

 may be economically made by the grower himself. The powder rec- 

 ommended in this circular has been designed by the acting chemist 

 with the hope that it will meet the need? of the fruit growers, espe- 

 cially those who cannot use the liquid spray. This dust spray will be 

 tested practically in the orchard of the Experiment Station during the 

 present season and it is hoped that many orchardists will apply it 

 and report results to the station. 



