177 



were scarcely at all yellowed, but were covered with dead and dry 

 patches or spots, sometimes iucluding almost the entire leaf, which 

 seemed to be not due directly to the extraction of the plant juices by 

 the insects, but rather to the sun-scalding resulting from the collection 

 on the leaves, in large drops or in masses, of the liquid honeydew. This 

 gave an aijpearance which might easily be mistaken for the result 

 of some fungus attack, and in fact Mr. P^mory supposed at first that 

 this was the nature of the trouble, and had had the matter investigated 

 by Mr. Waite, of the Division of Vegetable Pathology. The orchard 

 was for the most part of dwarf trees and was arranged in plots, rather 

 thickly planted, and covering an area of upward of 100 acres. The 

 Psylla was distributed over this entire tract, but was much more abun 

 dant in the plots of older trees. The young orchard, i^erhaps amount- 

 ing to one-third of the entire tract, was in vigorous condition and had 

 not been seriously afiected. The old Duchess orchard seemed to have 

 suffered the most. On these trees the adults were very numerous, 

 frequently L") or 20 resting along the midrib of a single leaf. They 

 were depositing tlieir eggs along the midrib on the upper surface, and 

 also thickly along the seriated margin of the leaf. I saw no eggs in 

 any amount on any other part of the leaf. At the time of my second 

 visit, July 31 to August 3, the eggs were much more numerous and 

 had been frequently deposited in small clusters, 5 to 8 together, along 

 the midrib and at the margin of the leaves. Scarcely any of the 

 eggs at this time had hatched, at least not more than 2 or 3 per cent, 

 and the adults were still almost as numerous as ever and busily ovipos- 

 iting. 



THE PSYLLA IN THE ORCHARD OF C. C. BROWN. 



The presence of this i^est in the orchard of Capt. Emory is not the 

 first instance of its occurrence in Maryland. The pear orchard of Mr. 

 C. V. Brown, of Pomona, Md., about eight miles south of Capt. Emory's 

 place, was also very badly infested, over a limited tract, in the summer 

 of 1891. The insect appeared during that year on pear trees next to 

 and in the vicinity of the house, and its presence was first noticed from 

 the fact that clothing put out to dry near the pear trees was covered 

 with the honeydew secretion. Examination showed that it was con- 

 fined to an area of 3 or 4 acres, which, however, was so thickly infested 

 that the leaves and fruit fell and the trees were so stunted and injured 

 that they have not since been in bearing condition until the present 

 year, when they have set a fairly good crop. Curiously enough, how- 

 ever, in this instance the Psylla disappeared entirely after the first 

 year and has not again put in an appearance in this orchard. I vis- 

 ite<l the orchard on August 1 and examined it very carefully, but failed 

 to find the least trace of the insect. Thorough search in other pear 

 orchards between and in the neighborhood of the two referred to failed 

 to show any indication of the Psylla in any of them. 



