238 PRODUCTIVE FARMING 



numbers of young are produced by a single insect, each one 

 of which in turn begins to produce young in five or six weeks 

 from birth. It is thus seen that where healthy insects of 

 this species are not killed before the warm weather begins, 

 the numbers may be so great by fall as to destroy or seriously 

 threaten the trees of the vicinity. 



These scale insects thrive not only on orchard and nursery 

 fruit trees, but are also found on hedges, some kinds of shade 

 trees, and roadside shrubs. This makes it difficult to totally 

 destroy the pest in any section where it has become firmly 

 established. 



Remedies. As this pest does not eat the tissues of the 

 plant, poisonous sprays are not effective. The covering with 

 which the insect naturally protects itself makes it a very 

 difficult enemy to fight. A few good spray materials have 

 now been found. Soluble oil is on the market under different 

 trade names; in these the oil and water are caused to mix 

 readily by use of certain chemicals. 



Lime-sulfur sprays are very successful in combating the 

 San Jose scale. One application is made in winter or early 

 spring before the buds of the trees begin to swell. Another 

 application is sometimes made in June or July when the 

 young, tender insects are abundant. This summer spray is 

 made very weak to avoid danger to the leaves. 



The early spring spraying and also the summer spraying 

 will be very valuable as a means of combating several dis- 

 eases such as peach scab and apple scab, and brown rot of 

 peaches. Thus the fighting of the San Jose scale is not, in 

 itself, a very serious problem for the fruit grower. 



EXERCISE. Insect Specimens. Let pupils bring to school 

 at any time insects which are injurious to plants in the home 

 garden or elsewhere. The leaflets issued by the Bureau 

 of Entomology at Washington will be helpful in the study 

 of the insects thus collected. 



EXERCISE. Preserving Specimens. Insect specimens 



