Treatment 



CESSATION OF FLOODING 



If a badly infested bog is not flooded at all for three years, it generally becomes 

 free of this pest, and sometimes it will do so in a year. This treatment is not 

 advocated because of the danger of winterkilling and of a great increase of 

 fruitworm infestation. 



REFLOODING 



Complete flooding for ten hours, during the night or when the weather 

 is cool, as soon as the small worms of the first brood become numerous, usually 

 about May 30, is often very effective. Generally it is necessary to repeat this 

 treatment once or twice, as soon as more worms appear, to get satisfactory con' 

 trol for the season, this often eliminating the second brood. Flooding for much 

 longer periods is not advocated because of possible injury to flower buds. 

 Delay of the flooding to insure completion of the hatch generally allows too 

 many of the first worms to pupate and develop a second brood. 



DUSTING 



Dusting with 50 pounds of clear pyrethrum dust (0.9 percent pyrethrins or 

 better in killing power) to the acre is a very effective control for the worms of 

 either brood. They can be treated as well and much more cheaply with 50 

 pounds of 5 percent DDT dust to the acre. These dusts may be applied when- 

 ever the worms seem too abundant. 



SPRAYING 



The following is an excellent spray for either brood: 7 pounds of derris 

 (4 or 5 percent rotenone) powder and 2 pounds of soap in 100 gallons of water, 

 400 gallons to the acre. Cheaper, and equally effective, 2 pounds of 50 percent 

 wettable DDT in 100 gallons of water, 400 gallons to the acre, is advocated. 



Pyrethrum soap makes an excellent spray for the first brood, but it tends 

 to stunt the small cranberries that are usually present when the second brood of 

 worms appear. 



The second brood must be treated as soon as hatching is general, usually five 

 or six days after the first worms appear, for the following reasons: (1) Because 

 of its partial suppression, this brood is usually well bunched in hatching: (2) 

 the worms are killed most easily when small; (3) if treatment is delayed, the 

 worms may injure the tips so that they will not bud well for the next year; 

 and (4) the worms that enter berries are not easily reached with a spray or dust. 



Fig. X. Remains of a Black-Headed Fireworm, 



Killed by Fungus, on the Under Side of a 



Cranberry Leaf. 



[10] 



