June '22 scientific notes 247 



Nicodust composed of lime treated with 5% of the 40% Nicotine sulphate is 

 proving very efficient in controlling young caterpillars, such as the leaf -rollers, tent- 

 caterpillars and cankerworms, but must be used before the worms are half-grown. 



E. O. EssiG 



The Foot Louse of Sheep. Linognathus pedalis Osborn, has been taken in the 

 Sacramento Valley, California, a number of times during the past year and seems to 

 be on the increase. 



E. R. DE Ong 



Arsenate of Lead Spray for Plum Curculio Kills Grasshoppers. The large winged 

 AmencanLocnst, Schistocer a americana Scud., has been very numerous in the peach 

 belt of Georgia during the latter part of April, and considerable damage has been 

 done by the feeding of this insect on small green peaches. In many orchards fruit 

 on every tree could be found damaged by the feeding of this locust. In one orchard 

 the damage was so severe that poisoned bran bait had to be resorted to. Most of the 

 feeding was observed just prior to the third arsenate of lead treatment for the cur- 

 culio. Observations made four days after the lead arsenate had been applied at the 

 rate of four pounds of the powder to the two hundred gallon tank for the curculio 

 showed that the treatment was also effective against these locusts. Many dead 

 ones were found on the ground, and appendages of some that had been partially 

 destroyed by ants were also observed. There was hardly a live locust to be found 

 in these orchards after the arsenate of lead had been used. 



Oliver I. Snapf, Entomologist, 



U. S. Bureau of Entomology, 



Fort Valley, Georgia 



Mosaic and Curly Leaf Diseases of Sugar Beets. — In the September number of 

 Phytopathology, pages 349-365, W. W. Robbins published an article entitled, 

 "Mosaic Disease of Sugar Beets." A summary of his article follows: "1. Mosiac 

 of sugar beet has become increasingly prevalent the last few years in steckling and 

 seed beet fields of northern Colorado and western Nebraska. It also occurs in 

 commercial beet fields near possible source of infection. 2. Mosiac of sugar beet is 

 distinct from curly -top of sugar beet. 3. The principal symptom is mottling of the 

 leaves, which may or may not be associated with their malformation. 4. Aphids 

 carry the infectious principle. 5. Under greenhouse conditions, an incubation 

 period on seed beets of approximately 24 days has been established; on seedling 

 plants from 12-18 days. Thus far, evidence of seed transmission is lacking. 7. 

 The virus retains its vitality in the steckling throughout the silo period. This is 

 the only means of wintering -over thus far known." 



In California, P. A. Boncquet described in Phytopathology VII, No. 4, pages 

 269-289, two types of diseases; namely, mottled leaf and black edge or black tip 

 of sugar beets. These two types of diseases are symptoms and malformations of 

 sugar beet mosaic, according to Robbins description and illustrations. 



Evidence to support Robbin's view that sugar beet mosaic is distinct from curly 

 leaf may be worthy of mention. Successive generations of non-infective beet leaf- 

 hoppers {Eutettix tenella Baker) have been bred on mottled leaf, and black edge or 

 black tip beets, and the hoppers were then transferred to healthy beets but not a 

 single case of curly leaf developed. On the other hand, when infective leafhoppers 

 were allowed to feed on mottled leaf and black edge or black tip beets, typical curly 

 leaf symptoms appeared. It is evident, furthermore, that Eutettix tenella is not 

 able to transmit mosiac of sugar beets. 



Henry H. P. Severin, Ph.D. 

 California Agricultural Experiment Station 



