17 



soned. If spraying for the first brood is omitted, that for the second 

 brood should be timed in the same way, and, because the worms now 

 spin up a greater amount of vegetation, the chances of killing them 

 off are greater. 



All things considered, the best insecticides for use on cranberry 

 bogs is arsenate of lead, either in the paste form as sold by certain 

 makers of insecticides or made up b}^ dissolving separately 4 ounces 

 arsenate of soda and 7 ounces acetate of lead in water enough for 

 that purpose, then combining the solutions in a tank to which 50 gal- 

 lons of water may be added. If the paste arsenate is used, 1 pound 

 in 40 gallons is lietter. 



Any sort of machine or pump may be used and any nozzle that 

 makes a reasonably fine spra3\ The point to be aimed at always is 

 the terminal growth, because it is there that the insects feed. Noth- 

 ing will be gained by driving the mixture into the body of the vines, 

 especially if they are long and densely matted. The conditions on the 

 bogs vary so much that every grower must determine his outfit accord- 

 ing to his own needs. In some cases horses can be used on the bogs 

 to draw a geared machine of large capacity; in others they are out of 

 the question; and so the size of tank from which the spraying is done 

 and the way in which it is mounted must vary according to circumstances. 



It may under some conditions be more satisfactory to appl}'' a dry 

 insecticide, and for this purpose there are now several "dust sprayers" 

 and "powder guns" on the market. By means of a fan blower a fine 

 powder can be rapidly and evenly distributed over a large area, and 

 this would naturally lodge just where it was needed. A good mixture 

 for such application is 1 pound of fine Paris green to 10 pounds of dry 

 hydrate or fresh air-slaked lime. The lime should be sifted, thoroughly 

 mixed with the Paris green, and the combination applied while the 

 vines are slightly moist. 



THE CRANBERRY TIP WORM. 



( Cecidomyia oxycoccana Johns. ) " 



This is a minute orange-red or yellowish grub (fig. 7, «), about one- 

 sixteenth of an inch in length, found in the growing shoots, whether 

 uprights or runners. It is comparatively rare on Cape Cod and is 

 not common on all the New Jersey bogs, though more plentiful there 

 than anj^where in Massachusetts. It appears on the vines soon after 

 they make a start, and the first indication of its presence is when the 

 small leaves of the tip cease to unfold and become bunched into a com- 

 pact, bulb-like mass. When this mass is opened,- from one to five, 



«Has been described and figured also as C. vaccinii Sm., not Osten Sacken. 



178 



4382— No, 178—03 2 



