62 



THE AMERICAN ENTOMOLOGIST. 



through the animal and vegetable king- 

 doms — whether the subject be a man, horse, 

 sturdy oak, or delicate strawberry plant. 

 Not that all diseases are due to loss of 

 vigor through starvation and neglect ; but 

 that a large number of them are, is well 

 known. 



The experience of the grape-grower of 

 France with the Phylloxera is one of the 

 most remarkable instances on record of 

 the success of what may be termed the 

 " resistant methods " of combating insect 

 enemies. After having searched in vain 

 for many years to find some practical 

 method of destroying this pest. Prof. Riley 

 in his remarkable investigations in this 

 country discovered that some of our native 

 American varieties were capable of resist- 

 ing it, i. e. of growing vigorously notwith- 

 standing the presence of the lice upon 

 their roots. This discovery opened a way 

 out of the difficulty, and the French are 

 successfully availing themselves of it by 

 using our resisting species as stock for 

 their more susceptible kinds. The Grape 

 Phylloxera is more or less abundant in all 

 of our vineyards, but owing to the rapid 

 and vigorous growth of most of our native 

 varieties it does comparatively little harm. 



But we have many kinds of insects that 

 attack our small fruits that cannot be con- 

 trolled upon this resistant system, and we 

 are compelled to combat them in a more di- 

 rect and vigorous way^ and among the first 

 to which I would call your attention are 

 those 



AFFECTING THE BLACKBERRY. 



Some ten years ago, the cultivators of 

 the Blackberry in various parts of New 

 Jersey noticed that the ends of the young 

 growing canes in summer would occasion- 

 ally curl, twist about, and often assume a 

 singular, fasciated form, resulting in an en- 

 tire check to their growth. The leaves on 

 these infested shoots did not die and fall 

 off, but merely curled up, sometimes as- 

 suming a deeper green than the healthy 

 leaves on the same stalk. At the approach 

 of winter the infested leaves remained firmly 

 attached to the diseased stems, and all 

 through the cold weather and far into 



the spring, these leaf-laden and diseased 

 stems were a conspicuous object in many 

 of the blackberry plantations of this State. 



If the infested shoots are examined 

 in summer, thousands of minute insects 

 of a pale yellow color and covered with a 

 powdery exudation will be found sucking 

 the juices of the succulent stems and leaves, 

 causing the crimping, curling, and twisting 

 of these parts as described. 



This parasite resembles somewhat an 

 ordinary green-fly {Aphis) or plant-louse, 

 but according to the observations of Prof. 

 Riley it belongs to the closely allied Flea- 

 lice family {Psyllidd), distinguished from 



[Fig. 17.] 



PsYLLA TRIPUNCTATA — hair line showing nat. size (after 

 Riley). 



the plant-lice by a different veining of the 

 wings, and by the antennae being knobbed at 

 the tip, like those of the butterfly, the knob 

 usually terminating in two bristles. These 

 insects jump as briskly as a flea, from which 

 characteristic they derive their scientific 

 name. The particular species in question 

 was called by Prof. Riley the " Bramble 

 Flea-louse [Psylla rubi*)" in the American 

 Entomologist (Vol. I, p. 225). It has in- 

 creased very rapidly during the past half 

 dozen years or more, and unless fruit- 

 growers make a more vigorous fight than 

 they yet have done, it will soon get the 

 mastery of most blackberry plantations. 

 The only practical method as yet discov- 

 ered for checking the ravages of this in- 

 sect, is, to cut off the ends of the infested 

 canes and burn them. This operation 

 should always be performed either in the 

 morning, or during cool wet weather, else 

 many of the insects will escape, and at all 

 times the severed shoots should be im- 



* It cannot be distinguished from Psylla tripunctata Fitch 

 (Catalogue of Homoptera, etc.), and, what is most singular, 

 the same species is very common on Pine trees all over the 

 eastern part of the continent, from Florida to Canada. — Ed. 



