212 THE NURSERY-MANUAL 



the spring. Dusting the foliage with sulfur will kill the red- 

 spider. 



PEAR PSYLLA. The pear psylla (Psylla pyricola) is a minute 

 yellowish flat-bodied sucking insect that occasionally attacks 

 the foliage of nursery pear trees early in 

 the season. The psyllas develop into minute 

 cicada-like jumping lice. The young psyllas 

 secrete a sweet sticky honey ~dew in which 

 a peculiar black fungus grows, giving the foli- 

 age a sooty appearance. There may be four 

 broods annually. 



Control. Spray for the adult psyllas, dur- 

 in g warm periods in December or March, with 

 tobacco extract, f of a pint in 100 gallons of 

 water, with 5 pounds fish-oil soap added. Good results have 

 been obtained by making an application of lime-sulfur solution 

 1 to 8 just after the leaf-buds open in the spring. If the psyllas 

 appear on the new foliage, make another treatment with the 

 tobacco and soap solution. 



TARNISHED PLANT-BUG. This sucking bug (Fig. 223) 

 attacks many species of plants. In feeding, it punctures the 

 buds and tender growing tips and sucks the juices. Peach 

 nursery stock is often seriously injured. The bugs kill the 

 tender tips, causing the tree to throw out lateral branches 

 which are in turn similarly injured, causing an overbranched 

 stunted tree. Pear and apple stock are often attacked but 

 seem able to outgrow the injury more easily than peach trees. 

 This insect is of great importance in spreading the fire-blight 

 bacteria in apple, pear and quince trees. The adult tarnished 

 plant-bug is about ^ inch in length and colored a dull yellowish 

 or greenish, mottled with reddish brown. The species is Lygus 

 pratensis. 



