390 



STATE BOARD OF AGRICULTURE. 



A very common affection of the foliage of blackberry, dewberry and raspberry 

 is the spotting due to a minute parasitic fungus called leaf-spot. The disease 

 gives rise to numerous purplish spots which later become lighter in the center 

 In which several small black pimples appear. These little pimples are hollow 

 bodies which give off spores through a minute opening in the apex. The spores 

 are slender curved bodies without color and are scattered by rain and wind. 



While the leaf-spot fungus is often abundant it seems to do but little damage 

 especially on plants that are sprayed and cultivated. 



STRAWBERRY DISEASES. 



I.EAK-SPOT DISEASE OF Sm.UVnERRY. 



(Sphaerella fragariae (Tul ) Sacc.) 



-^V-v^ 



Fig. 40. — a, A leaf of strawberry affected with leaf bliKht; b, spore bearing tuft of mycelium 

 bursting through the epidermis of the leaf; c, summer spores arising from apex of a resting 

 spore case; d, summer spores (conidia), one germinating; e, .section of a spore pustule 

 (spermogonium), produced in summer; f, section of resting or winter spore case (perithec- 

 ium). found in tissues of old diseased leaves which liavc lain on the ground over winter; 

 g, a spore sac (ascuS), containing eiglit two celled winter spores; h, a winter .spore (asco- 

 epore), very highly magnified. (Original.) 



