Page ?(5 



BETTER FRUIT 



February 



PEAR TREE SLUG 

 a, Adult fly; b. Larva or slug, with slimy covering 

 removed: c. Same, in natural condition; d, Leaves 

 showing slugs and their injuries. 



Pears are subject to two serious dis- 

 eases in this state, the most important 

 being pear blight, which also attacks 

 apples, quinces, loquats and other wild 

 forms of the pome family, as the Cali- 

 fornia holly. The method of treatment 

 has been so widely discussed within the 

 past years that every grower is more 

 or less familiar with it. It should be 

 understood that the various patent rem- 

 edies for pear blight are fakes. The 

 origination of these patent remedies has 

 kept pace with the invasion of pear 

 blight as it has gradually swept across 

 the United States from East to West, 

 and each new pear blight territory has 

 its promoters of supposed remedies to 

 be put in holes bored in the trunks of 

 trees or poured around the roots. The 

 only solution of the difficulty for the 

 susceptible varieties is to follow the 

 recommendations already given, for the 

 hundred years and more that pear blight 

 has been known in New York state has 



given time for a careful investigation of 

 all possible remedies. 



Pear scab, in most sections, is con- 

 trolled by two sprayings with bordeaux 

 at the time the cluster buds are opening, 

 and another after the fruit sets, as re- 

 commended in one of the state experi- 

 ment station bulletins. There are locali- 

 ties and seasons in which later sprayings 

 will no doubt be required. 



The cherry has its troubles in the way 

 of sunburn and die-back. Sunburn some- 

 times does considerable damage on 

 young trees, and can undoubtedly be 

 prevented to a large extent by thorough 

 whitewashing of the trunks and lower 

 parts of the framework limbs. Many 

 opinions could be offered concerning the 

 die-back, but definite information is still 

 lacking. 



Finally, we may consider the apple. 

 Pear blight afifects it seriously in some 

 sections, and the treatment is along the 

 same line as that applied to pears. Apple 

 scab is not as common in California as 

 one might expect from the climatic con- 

 ditions of some of the apple sections, and 



Figure 1, Brown mile; 2. Red spider; 3, 4, 5 and 

 fi, LarvEc, pupa, adult and egg of Scymnus punc- 

 tum. Figure 1 enlarged. 66 times; 2, 1.33 times; 

 3. 4, a and 6, 30 times. Original. Miss M. A. 

 Palmer, delineator. Colorado Experiment Station. 



WOOLLY APHIS, ROOT FORM 

 a, Small root showing swellings caused by the 

 lice; b, Wingless louse, showing woolly secretion; 

 c, Winged louse. (After Saunders.) 



its control is relatively easy. Spraying 

 with bordeaux or lime-sulphur at the 

 time the leaf buds are opening, and, pos- 

 sibly, one or two later applications of 

 bordeaux, depending on the weather 

 conditions, will control this trouble. In 

 this locality, as well as other coast sec- 

 tions, bordeaux should be used with cau- 

 tion, for the fogs and humidity are apt 

 to cause bordeaux injury to the fruit as 

 well as the foliage. 



The malady known in this section as 

 "sappy bark disease" is still an unsettled 

 problem, both as to its cause and means 

 of control. 



At present the most serious pest with 

 which the apple growers of Pajaro Val- 

 ley have to contend is the apple powdery 

 mildew. It is relatively quite common 

 throughout the state — in fact throughout 

 the arid West — but does most damage 

 along the coast. 



It usually occurs on the lower side of 

 the leaf and has a white powdery 

 appearance, as the name would indicate. 

 Even a small infection is sufficient to 

 stunt the growth and cause a crinkling 

 of that particular portion of the leaf, and 

 when several infections become estab- 

 lished at once on a young growing leaf 

 the result is an almost immediate check- 

 ing of growth and the stunted leaf 

 becomes very much crinkled. The cur- 

 rent year's twigs are also very suscep- 

 tible to infection, becoming entirely cov- 

 ered with the white powdery growth. 

 As a terminal bud is expanding the 

 emerging leaves may become infected on 



SCURVY BARK LOUSE 

 a, Twig showing scales of female louse; b, Twig 

 showing scales of male louse; c, Scale of female, 

 greatly enlarged; d, Scale of male, greatly enlarged. 



both the upper and lower surfaces as 

 rapidly as they appear, and in the end 

 the bud itself may be killed, leaving only 

 a rosette of tiny leaves, which soon dry 

 up. In that case the terminal growth of 

 the tree is practically nil. The white 

 powdery substance characterizing the 

 mildew consists of myriads of spores, 

 which are easily blown about the orchard, 

 and during the foggy nights they ger- 

 minate and start new infections. The 

 lower surface of the leaf is more sus- 

 ceptible to infection than the upper, 

 hence it is usually on the lower side that 

 the mildew occurs. Obviously with this 

 stunted foliage the tree is not capable of 

 producing nourishment for all the growth 

 to which it is entitled; and no doubt, too, 

 the effect is frequently felt on the setting 

 of next year's fruit buds. It appears 

 that the mildew has a toxic or poisonous 

 effect upon the tree, which seems to 

 make it more susceptible to further infec- 

 tion as well as stunting the growth. 

 The white powdery spores appearing 

 during the summer are relatively short- 

 lived. The natural provision which the 

 fungus has for bridging over from one 

 season to another is by means of more 

 resistant resting spores than are pro- 



FALL WEB WORM 



a and b, Caterpillars; c, Chrysalis; d, Moth. 



