408 THE FUNGUS PESTS OF GARDEN PLANTS 



produced, it is, however, certain and deadly in its effects ; when it 

 is enlarged 300 diameters under the microscope it is seen as 

 at B. The habit resembles that of the Dactylium, but the whole 

 growth, including the spores, is much smaller, and the spores them- 

 selves are pale brown, not pink. 



Up to the present time both fungi have defied all attempts at extir- 

 pation ; they are both parasites, their roots or mycelia grow within 

 the plants attacked, and so are virtually beyond reach. Good venti- 

 lation and hand picking when the diseases are in the earliest states 



may sometimes prevent the en- 

 tire destruction of the Tomato 

 plants, and the dissemination of 

 Sulfosttatite coprique is believed 

 to be useful, but we know of no 

 conclusive experiments. 



Tomatoes are sometimes 



X-300" fe ^ ^> / 



seriously attacked in the roots 

 by eel- worms, which are in every 

 way identical with the eel-worms 

 of the Cucumber disease. And 

 the Potato fungus, Peronospora 

 mfestans, sometimes attacks Tomatoes. 



The black patches often seen on Tomato stems and leaves are not 

 due to the fungus which causes the black spot on the fruit, they 

 appear to be due to some cultural defect, possibly in reference to 

 the root growth, but the eel-worms of the roots are not associated 

 with the black spots on the stems. 



THE 'BLACK-SPOT' DISEASE OF 



TOMATOES 



Diseased fruit, natural size ; the parasitic fungus 

 Cladosporium lycofersici enlarged 300 dia- 

 meters 



