1892.] PUBLIC DOCUMENT — No. 33. 233 



Dr. J. B. Paige of the Agricultural College, specimens of 

 trout eggs attacked by fungous filaments. These filaments 

 were not in the fruiting stage ; but when dead flies were 

 thrown into the water containing the eggs, they were 

 promptly attacked by similar filaments, which soon developed 

 both non-gexual and sexual reproductive organs, from which 

 the fungus was readily determined as Achhja racemosa Hild. 

 I am informed by H. E. Maynard, Esq., of Northampton, 

 that the eggs suffer most when first placed in the hatching 

 trays. It is generally believed that only dead eggs are 

 attacked ; yet the fact, which is commonly observed, that, 

 if the eggs are not removed from the trays as fast as they 

 die, the fungus will extend to all the eggs, shows plainly 

 that this cannot be the case. If it were able to attack only 

 dead eggs, the fungus could not be a source of harm, and its 

 presence in the trays could not endanger living eggs. It 

 does not, as far as I can learn, attack the young fiy after 

 hatching. 



The only efiective means of preventing the spread of this 

 affection lies in the frequent removal of all dead eggs from 

 the hatching trays. 



Rust of Poplars. — The European black poplar [Populus 

 nigra L.) has been considerably planted on the grounds of 

 the Agricultural College and elsewhere in Amherst. 



The trees are attacked annually in September by the 

 poplar rust {Melampsora populina (Jacq.) Lev.), and 

 during the past two seasons the attacks have been very 

 severe. The disease first shows itself in the yellowing of the 

 lower leaves, due partly to the fading of their natural color 

 in consequence of the presence of the parasite, and partly to 

 the development on their lower sides of the abundant deep- 

 yellow summer-spore masses of the rust. There now follows 

 a definite upward progress of the disease, and when the 

 middle part of the tree is reached, the lower leaves are 

 falling in great numbers and the lower limbs soon become 

 stripped of foliage. This results in two to three weeks after 

 the first appearance of the disease. By the time they fall 

 the leaves have become brown in color, from the further 

 degeneration of their pigment and the replacement of the 

 summer spores by the brown crusts of compacted winter 



