A FEW ORCHARD PLANT RICE 5 
Slick the sap of plants, is beneath the head and does not show in the . 
figure. 
Each species of plant louse has its special food-plant or plants 
upon which it feeds. Some species are very restricted in food, 
having but one, or at most a very few closely allied plants, to live 
upon, while other species have a few preferred plants but also at¬ 
tack others in smaller numbers, and under certain conditions may 
adopt a very wide range of plants, especially in the spring, when 
nearly all growth is tender and succulent, and again in the fall 
after the preferred food plants may have ripened or have been 
killed by frosts. 
Perhaps one of the most important things to be known, from 
an economic standpoint, is that very many plant lice have a reg¬ 
ular alternation, or change, of food plants. Such lice usually mi¬ 
grate upon certain trees or other woody plants in the fall, upon 
which eggs are deposited to remain over winter and hatch in the 
spring to start the next year’s broods. These spring forms, after 
going through one or more generations, acquire wings and go, 
either Avholly or in part, to their summer food-plants, which are 
usually plants that will die down in the fall. 
But it is a condition that we face. The lice are in our 
orchards. How can we recognize them? What are their habits? 
How can we prevent their injuries to the fruit crops? These are 
the questions we shall specially attempt to answer, for the fruit 
growers. 
APPLE PLANT LICE 
THE WOOLY APPLE APHIS 
{Schizoneura lanigera Hausm.). 
Plate I, Figs. 9, 10, ii, and Plate III, Figs. 3, 4. 
If Colorado orchardists should vote their opinion as to what 
ought to be called the worst orchard pest in the state, it is very 
doubtful whether the codling moth, or the woolly aphis, would 
carrv off the honors. 
m/ 
Most plant lice are leaf feeders, but this one confines its at¬ 
tacks to the tender bark, and it is not particular whether it is the 
bark of the trunk, limbs or roots, if it is only tender enough to 
enable the louse to insert its beak. When very abundant the lice 
sometimes attack the stems of the leaves and fruit. 
PAST HISTORY. 
No one seems to have determined with much certainty the na¬ 
tive home of this insect. In fact, it may be said to be a louse 
without a country, as it is everywhere disowned. The earliest 
references to it that we have found dates back to 1787, when it was 
