234 AGRICULTURE ON THE PACIFIC SLOPE 



take them out and put them aside ; do any of these de- . 

 velop rot? Can you destroy the spores by boiling the \ 

 water as well as by adding formalin ? Place some sound 

 lemons in a box, and lay an infected lemon on top of 

 them. Does it infect any of the lemons except those it 

 actually touches? This shows how important it is to 

 sort out all infected lemons when packing the boxes. 



Brown rot of stone fruits. This attacks apricots, plums, 

 and peaches, causing the young fruit to turn brown and later 

 on to shrivel and dry up on the tree. The fruit is then cov- 

 ered with a coat of the mold. It may be checked by spray- 

 ing with Bordeaux mixture. (Oregon Experiment Station, 

 Bulletin 57; Washington, 83.) 



Potato and tomato blight. The fungus causing thes(L 

 diseases does not merely attack the surface, but penetrates 

 into the plant. It causes the dreaded potato blight of the 

 East and Europe, and has caused some trouble in this part 

 of the country. It sometimes attacks tomatoes during wet 

 weather, and is then called winter blight. It is important 

 to know that it is different from the summer blight of the 

 tomato (page 246), which is not affected by spraying. 



Thft wjnf.Ar t?1if>j]+ appears as dark spots on the leave^, 

 stems, and fruit. Soon the whole vine becomes black and 

 dead, with green spots remaining here and there, exactly 

 as though the field had been struck by frost. The best 

 remedy is spraying with Bordeaux mixture. (California 

 Experiment Station, Bulletin 175; Washington, 46, 83; 

 Wyoming, 71.) 



A similar fungus, the downy mildew, has caused severe 

 loss on the onion seed farms during wet weather. 



Damping off. Whenever young plants grow closely 



