688 



attacked. This scale is free from effective parasites or predaceous 

 enemies, but can be controlled by fumigation between 15th July and 

 15th August, and Saissetia oleae (black scale) between 1st August 

 and 1st January. 



Weldon (G. p.). Potatoes as a Trap-Crop for Wireworms. — Mfhly. 



Bull. State Commiss. Hortic, Sacramento, Cal., iv, no. 8, August 



1915, p. 374. 

 A crop of beans at Davis, California was saved from the attacks of 

 wireworms by the use of small pieces of potato placed between the 

 rows, while a patch of about 30 acres, which remained untreated, was 

 entirely destroyed. Though this method is only in the experimental 

 stage, it seems to possess great possibilities. 



Weldon (G. P.). White Fly at Marysville,— M^^??/. Bull State Commiss. 

 Hortic, Sacramento, Cal., iv, no. 8, August 1915, pp. 386-388, 1 fig. 



Since the discovery of Aleurodes (Dialeurodes) citri (whitefly) at 

 Marysville in 1907, inspections made each season have revealed its 

 presence, but not generally to a serious extent. Efforts at complete 

 eradication have been unsuccessful. In order to test certain oil sprays 

 under California conditions, an experiment was conducted at Marysville 

 on 7th December 1914. An examination made on 19th January 1915 

 showed that all strengths of miscible oil and distillate emulsion had 

 been satisfactory. Further experiments were performed on 15th 

 February ; miscible oil no. 1 was used at 6 per cent, strength, with 

 the addition of 2 quarts of liquid whale-oil soap to 200 gals, of spray. 

 A pressure of from 180 to 200 lb. was used. Kesults showed that 

 98^^ per cent, of larvae and pupae were killed. In the preliminary 

 work there was apparently no scorching of foliage at the maximum 

 strength of 10 per cent. The later spraying with 6 per cent, miscible 

 oil, performed just before the time of flowering, resulted in almost 

 total defoliation and more or less severe injury, especially if carried 

 out on a hot day. Spraying performed in cool, cloudy weather did 

 little if any harm to trees, though it caused some foliage to drop. 

 Later in the season, as the new foliage appeared, AjjJiis gossypii became 

 very abundant and was the cause of an additional set-back to the trees. 

 Spraying should therefore be done in winter or early spring. 



Crvwford (D. L.). Potato Curly Leaf.— M//??y. Bull. State Commiss. 

 Hortic, Sacramento, Cal, iv. no. 8, August 1915, pp. 389-391, 2 figs. 



Potato plants in the San Gabiiel region are attacked by Euthrips 

 occidentalis, with considerable injury to the leaves and crop. Curling 

 of the leaves results when the expanding buds or very young leaves 

 are attacked; older leaves only become spotted. Injury by 

 E. occidentalis is invariably followed by infestation by a fungus, 

 Macrosporium- solani. The dwarfing of the plants is often very 

 severe. The yield of tubers is seriousiy reduced, averaging one-fifth 

 to one third of the normal crop. In addition to potato, many 

 garden flowers, as well as oranges and lemons, are attacked. The 

 incubation period of the egg is less than a week. The larvae mature 

 in a week after hatching. The adult lives for several davs after 



