40 MASS. EXPERIMENT STATION BULLETIN 388 



Ferrous Sulfate. Dry ferrous su'fate, 40 pounds per square rod used early in 

 June, killed 90 percent of long-leaved asters {Aster spectahilis and A. Novi- 

 Belgii). The same treatment applied in July, when the asters were a foot high, 

 killed only 25 percent. 



Spike rush {Eleocharis tenuis) was controlled well with ferrous sulfate broad- 

 casted at the rate cf 40 pounds per square rod, June applications giving nearly 

 complete kills while those made in July and August were less effective. Two 

 competent growers reported the treatment as 95-100 percent effective when 

 used in May. 



Ferrous sulfate must be brushed off the cranberry vines when it is used in 

 broadcast applications of 30 or more pounds per square rod. 



Kerosene. Repeated experiments with kerosene showed the least injury to 

 cranberry vines when it was applied before 10 a. m. or after 5 p. m. in June, 

 July, and August. Mid-day applications, even with the air temperature below 

 80° F., injured cranberry tips and runners considerably. Recent tests of kerosene 

 spraying in the early morning when the vines and weeds are wet with dew showed 

 no injury to the cranberry vines, while the weeds seem.ed as sensitive to the 

 kerosene as when sprayed under dry conditions. 



Water white kerosene, 600 gallons per acre, gave 100 percent kill of loosestrife 

 {Lysimachia terrestris) when applied before this weed was 5 inches high. The 

 same kill was obtained later by mowing the taller loosestrife plants before spray- 

 ing with kerosene. 



Borax. Commercial borax, applied in July, 100 pounds per acre, killed Joe- 

 Pye weed {Eupatorium purpureum) with little or no injury to cranberry vines. 

 Heavier applications injured the vines. 



Root Grub Flooding and Bog Weeds. Nine bogs flooded from mid-May to mid- 

 July to kill grubs were examined in early September and late October to learn the 

 effect of this flood on bog weeds. It had prevented no annual weeds from growing 

 on the bogs but had shortened the season of several species so that they had 

 failed to flower; others, like summer grass {Panicum verrucosiim) and ragweed 

 {Ambrosia artemisiifolia) , had not attained normal growth but had flowered and 

 seeded profusely; the trailing bramble {Ruhus hispidus), rice cut-grass {Leersia), 

 and wild bean {Apios tuberosa) had been reduced 90 percent; and the coarse 

 bramble {Rubus sp.) and Jtinciis rushes had been killed entirely. Half the loose- 

 strife {Lysimachia) and three fourths of the hair-cap moss {Polytrickum) had been 

 killed where the water was over 18 inches deep, but these weeds had not been 

 reduced much where the water was shallow. As many as 28 other species of 

 perennial weeds grew more or less normally after the flooding. 



COOPERATIVE CRANBERRY INVESTIGATIONS 



Conducted by the Bureau of Plant Industry, United States Department of Agri- 

 culture, in cooperation with the Massachusetts Agricultural Experiment Station 



H. F. Bergman, Senior Pathologist, Division of Fruit and Vegetable 

 Crops and Diseases, in Charge 



Development of Strains of Cranberry Resistant to False Blossom. (H. F. 



Bergman.) Nearly 1800 hybrid cranberry seedlings in pots were brought to 

 East Wareham from Beltsville, Maryland, early in June 1941. This lot is part of 

 the seedlings obtained from crosses made at East Wareham in 1938. They were 

 set out temporarily on the State Bog and are to be transferred in 1942 to an 

 area of new bog provided by the A. D. Makepeace Company of Wareham, Mass- 



