-16- 



a slower growing raspberry plant will often have less disease pro- 

 hlems . 



3. Apply fungicides at the correct intervals. Fungicides 

 (Table 1) are useful in reducing spur blight when applied as pro- 

 tectants during the growing season, and as eradicants on dormant 

 canes . 



During the growing season, use captan or ferbam. Apply the 

 first spray when new canes first appear. Apply subsequent sprays 

 at 14 day intervals, up to 2 weeks before harvest. If rain is 

 particularly heavy, that is, in excess of two inches, it may be 

 necessary to reapply the fungicide before 14 days have elapsed. 

 This treatment usually requires 4 or 5 sprays in a season. The 

 most critical stage is at early bloom. A spray should be scheduled 

 at early bloom for maximum effect. 



At bud swell, and when canes are dormant in late fall, a lime 

 sulfur treatment may be applied. Bordeaux (3-3-50) may be applied 

 when new canes are 8 to 12 inches high. These applications are 

 designed to kill the fungus in bearing canes. 



Future Developments 



Unfortunately, there are no raspberry varieties resistant to 

 spur blight. However, sources of resistance have been found, and 

 resistant varieties are being bred. Resistant varieties should 

 provide the best solution to spur blight problems. 



Table 1. Fungicides for Spur Blight 



Dormant and Early Spring 



Fungicide Amt/100 gal Timing 



Lime sulfur 1 to 4 gal No later than bud break 



or 

 Bordeaux 6 lbs spray lime No later than 12 in. of 



plus growth on new canes 



6 lbs copper sulfate 



Bud Break Through Harvest 



* 



Fungicide Amt/100 gal Timing 



Captan 501 WP 2 lbs At 10-14 day intervals; 



or maintain good coverage 



Ferbam 761 WP 2 lbs especially at early bloom 



Apply approximately 200 gal/acre in mature plantings. In small 

 plantings, spray until plant surfaces are throughly covered. 



