774 THE MONTHLY BULLETIN. 



The Hop Flea Beetle. 



The hop flea beetle is a small black beetle with a metallic tinge and 

 appears in the spring attacking the hop plants as soon as they appear 

 above ground. Its work is characterized by the skeletonized leaves. 

 On page 231 of "Injurious and Beneficial Insects of California," E. 0. 

 Essig recommends the thorough cleaning of the hop fields and burning 

 the rubbish to destroy the hibernating beetles. 



DISEASES OF PLANTS. 



Pear Blight. 



The work of cutting out portions of the trees infested with pear 

 blight (Bacillus amylovorus) should be continued until all signs of 

 the dread disease have been eliminated from the orchard. As has 

 been stated before, the blight causes the leaves, blossoms and young 

 fruit to wither and turn black on the affected portions whicli do not 

 fall, remaining attached to the twigs during the winter. The disease 

 proceeds downward into the larger branches which are often killed 

 very rapidly. Care must be taken to disinfect the pruning tools with 

 a solution of corrosive sublimate (bichloride of mercury) 1 to 1,000, 

 and to cut below any sign of the affected area at the time when the 

 diseased parts are removed and subsequently burned. 



Stem Rot of Alfalfa. 



According to the CaliforniM Auricn'tural Experiment Station, a stem 

 rot fungus causes considerable damage to alfalfa at times in this State, 

 as well as in other state.s. The fungus appears to be a cosmopolitan 

 species affecting various plants all over the world. They^ describe the 

 characteristic work of this fungus as follows : The stems wilt and die 

 after nearly reacliing maturity. The infestation appears to be scat- 

 tered the attacked stems here and there in the fields are easily con- 

 trasted with the healthv green appearan"e of other stalks. The disea«!e 

 is particularly abundant during the spring when the ground is moist 

 and where the stand of alfalfa is .so thick as to shade the ground. The 

 examination of an affected stem shows a decayed base covered more or 

 less with a white mold. No remedy can be suggested other than the 

 plowing up of badly infested fields, which should be planted to other 

 crops for several years. 



Shot-Hole Fungus of Almond Trees. 



This fungus, as suggested by its name, gives a shot-hole effect to 

 the almond leaves. The young twigs are also sometimes spotted. A 

 strong attack of this disease defoliates the trees early in the season, 

 the crop being badly injured as a result. Control measures consist in 

 sprayinf? with Bordeaux mixture, ,5-5-50 formula in the spring as the 

 buds are opening. 



Shot-Hole and Fruit Spot of Apricot. 

 This disease is also knov:n as the peach blight fungus and causes the 

 spotting of the fruit of the apricot, as well as a shot-hole effect on the 

 leaves and killing of the buds. If the apricot orchardist whose trees 



'Ralph E. Smith and 'Rli^aheth H. Smith. California Plant Diseases. California 

 A»rl. Exp. Sta. Bull. No. 218, 



