36 Station Bulletin 372 



Blueberry Culture 



Plots were started this year in the dry sandy plains at Madison. The 

 area is covered with blueberry bushes and it has responded well to burning. 

 Spring frosts and summer droughts are still to be evaluated as ecological fac- 

 tors. 



The species of blueberry, Vaccinium canadense, predominates the north- 

 ern third of New Hampshire and seems to escape spring frost which may be 

 due to resistance of the plant blossoms to low temperatures or to later blos- 

 soming than the species (Vaccinium angustifolium) found in central New 

 Hampshire. 



Further studies of controlling weeds in blueberry fields led to the use 

 of weed-killing chemicals. Sulfamate used at concentration as dilute as %2 

 pound per gallon was found toxic to the blueberry plant. 



Boron crystals broadcasted at the rate of one pound per 100 square feet 

 killed hardback (Spiraea tomentosa) without injury to blueberry plants. 



2,4-D when diluted with water to 300 ppm of the 2,4-Dichlorophenoxy- 

 acetic acid, killed sweet fern (Comptonia peregrina) without injury to blue- 

 berry plants, but higher concentrations resulted in some injury. There was 

 evidence in a commercial blueberry field treated with a 7-7-7 fertilizer at the 

 rate of 1000 pounds per acre that the blossoms resisted spring frost more 

 than did blueberry blossoms in unfertilized areas. 



W. W. Smith 



Breeding Work and Varietal Tests 



The Van Buren, Fredonia, Kendaia, and Worden grape varieties main- 

 tained their position at the head of the list for varieties adapted to the climate 

 of southern New Hampshire. These varieties are too tender for growing in 

 the north without winter protection. 



An everbearing red raspberry resulting from Taylor seed pollinated 

 with Nectarberry has been introduced. It is a very firm berry which begins 

 ripening its fall crop by August 20. The fall fruiting area is often two feet 

 or more in length hence there is a possibility of a paying crop on new wood. 



Peach seedlings from hybrids made in 1944 by the use of North Cau- 

 casus peach pollen sent in by mail from Beltsville, Maryland, and used on 

 commercial varieties at Durham have made an unusual growth. They have 

 a good crop of fruit set in 1947, which is their third year from seed. One 

 of the seedlings is a cross between Peen-to and the North Caucasus peaches. 

 The characteristic shape of Peen-to predominates. 



Hybrids and back crosses of strawberries involving wild hybrids and 

 late hybrids show promise for high yield, good quality and freedom from 

 disease. 



A. F. Yeager, L. p. Latimer 



Cultural Practices 



Since first applying the mulch treatments it has been found that total 

 yield has been greatest on trees mulched with hay and lowest on unmulched 

 trees. Foliage has been paler green in color on sod and sawdust mulched 

 trees and twig growth has been greatest with hay mulch. In other charac- 



