INSECTS AND DISEASES. 317 



where they have less nourishment, are left from four to five inches 

 long. 



" Understanding this mode of pruning, nothing is easier than to 

 form pyramidal pear trees of the most perfect symmetry and beauty 

 of form. But in order to have the branches regularly produced 

 from the ground to the summit, you must plant a tree which is only 

 a couple of feet high, so that you can form the first tier of branches 

 quite near the ground, by cutting back the leader at the very outset ; 

 for if the tree is once allowed to form a clean body or stem, of course 

 it is impossible afterwards to give it the requisite shape and fullness 

 of branches at the bottom." 



All this our readers will understand relates more especially to 

 the art of pruning, as adapted to high or garden culture. Standard 

 trees in the orchard require only the same or similar pruning to that 

 pursued in the Apple ; very few trees, in fact, requiring aught but a 

 thinning out of branches, or rather a preventing, while young, of the 

 branches becoming too thick. 



Insects and Diseases. The Scolytus pyri is an insect described by 

 Harris. This is by some counted as the cause of a species of blight. 

 Its presence has, however, been rarely met with, and doubts arise 

 among many cultivators whether it is as prevalent, and the cause of 

 as much destruction, as reported. 



The Bupestris divaracata, and perhaps some allied species, is found 

 in the larvae state under the bark, on the bodies of both the Pear and 

 Apple ; and what is often taken for sun-blight, is the effect of this 

 insect. The bark appears blackened on the body of the tree, on the 

 South or Southwest side. Cutting it away carefully, and destroying 

 the larvae in months of July to September, and washing the body first 

 with lye-water, or strong soap-suds, and covering it with a coating of 

 gum shellac, dissolved in alcohol, is the remedy. 



The slug Selandria cerasi appears on the leaf of both Cherry and 

 Pear in June, July, and August. It is about half an inch long, of a 

 dull, greenish brown, slimy, shining, offensive appearance. It is 

 easily destroyed, if taken in time, by scattering ashes or even dirt 

 over the leaves early in morning, or while the dew is on, following 

 up the application some four or five days. The frozen-sap blight, 

 etc., often so destructive to trees in the West, we have remarked on 

 in previous pages, and refer thereto. 



Bark Lice, or Scale insects, are often found upon the Pear, as well 

 as the Apple. See " Apple Insects," for remedies. 



" The Psylla, or jumping louse, is probably identical with the same 

 species that infests the Pear tree in Europe. In some of its forms it 



