34 THE MONTHLY BULLETIN. 



It is stated that owing to the habits of the caterpillars the usual 

 arsenical sprays will probably not be effective. County commissioners 

 are requested to be on the lookout for this pest and fruit growers also 

 will confer a favor on the State Commissioner of Horticulture if they 

 will keep a watch fur this destructive insect. It is possible that it will 

 also attack plum, cherry or almond trees. Specimens of work thought 

 possibly to be that of this insect should be forwarded to the State 

 Insectary. 



The other new pest is a fungous disease of poplars and cottonwoods. 

 known as the European poplar canker. It attacks the twigs, limbs and 

 trunks of practically all the poplars and cottonwoods. The effect of the 

 disease is described as follows: 



"It appears first in the form of cankers or depressed dead areas in the 

 bark, much in the same manner as in case of the blight of chestnut 

 trees which is caused by a distinctly different fungus. Cankers are 

 formed on the point of attack, spread rapidly and often girdle the t\\ igs, 

 limbs or trunk at the point of attack, killing the part above the canker. 

 Trees attacked on the trunk become 'spike-topped. - The death of limbs 

 and twigs gives the trees a ragged appearance which spoils their beauty 

 ami later kills them. This is especially the case with black poplars 

 winch are frequently planted in rows along boulevards and avenues." 



It is said that the disease is even more severe on nursery stock, these 

 being readily attacked by the fungus and ruined within a very short 

 period of time. 



The disease is said to be prevalent in small areas of the following 

 states: New Hampshire, Massachusetts, Rhode Island, Connecticut, New 

 Jersey, Pennsylvania, Delaware, Maryland, Ohio, Nebraska and New 

 .Mexico. 



It would be very desirable to obtain additional information as to 

 whether this disease occurs in California, and owners of diseased poplar 

 and cottonwood trees are requested to notify the Horticultural Com- 

 mission and to send in specimens. — G. H. H. 



Concerning Hippodamia convergens. — For several years now the 

 State Insectary has been shipping out each season an enormous number 

 of the very valuable red ladybird, Hippodamia convergens. These 

 insects congregate for hibernation in large quantities in the mountain 

 canyons which renders their collection a comparatively easy matter. 

 This work has not been developed to the limit, however, for the reason 

 that we have never known just how much good we were accomplishing 

 by this artificial handling. The question has not been investigated, 

 mainly on account of lack of time and assistance. We believe that a 

 thorough study of this ladybird in the mountains, fields and laboratory 

 will enable us to measure in at least an approximate way just what from 

 a practical standpoint is accomplished by the work, so that it may be 

 conducted in a more intelligent manner in the future. We have 

 arranged to take up this study during the coming year, in cooperation 

 with the U. S. Department of Agriculture, and the Bureau of Ento- 

 mology has kindly Incited Mr. W. M. Davidson at the Insectary for the 

 purpose of studying this problem along with others concerning pre- 

 daceous insects. — H. S. S. 



