l88 Diseases of Greenhouse Crops 



spores within the affected tissue of the leaf or tuber. 

 However, Clinton succeeded in developing what ap- 

 peared to be oospores of the fungus in pure culture 

 on oat agar. The oogonia appear as swollen terminal 

 heads, cut off from the main thread by a cross wall. 

 The antheridium resembles that of P. phaseoU. Ma- 

 ture oospores have a medium thick, smooth, hyaline 

 wall. How the oospores germinate is unknown. 



Control. Late blight of tomatoes may be con- 

 trolled by spraying. The best results are obtained 

 by using 5-5-50 Bordeaux. 



Buckeye Rot 



Caused by Phytophthora terrestria Sherb. 



Buckeye rot is a disease which attacks the fruit. 

 The trouble seems to be new and has been recently 

 described by Sherbakoff.* So far as is known, the 

 disease has appeared only in Florida. 



Symptoms. The disease, as the name indicates, 

 appears as pale to dark greenish-brown zonate spots 

 on the fruit. The rot is hard and somewhat dry 

 when the fruit is green, but becomes softer as the 

 tomato ripens. It usually begins at a point where 

 the fruit touches the ground, which is most com- 

 monly at the blossom end, and might be mistaken 

 for blossom end rot were it not for the characteristic 

 zonations. 



The Organism. The mycelium is at first continu- 

 ous, then septate. Conidia germinate by means of 



* Shetbakoff, C. D., Fhytopath, 7:119-129, 1917. 



