198 



2 U.S. gals, water, in which 2 oz. laundry or fish-oil soap have been 

 dissolved; or a 10 per cent, kerosene emulsion, made by dissolving 

 I lb. laundry or fish-oil soap in 1 U.S. gal. hot soft water (or water 

 s'oftened with sal soda), adding while still hot 2 U.S. gals, kerosene 

 oil. The mixture should be thoroughly churned for ten minutes 

 and then diluted with 17 U.S. gals, soft water for use. Where the 

 plants are beyond recovery, pure kerosene may be used. 



Davis (J. J.). Cabbage and Radish Root Maggots. — Purdue Univ., 

 Dept. Agric. Extens., Lafayette, Ind., Leaflet no. 123, November 

 1921, 4 pp., 3 figs. [Received 11th February 1922.] 



The life-history and habits of Phorhia brassicae, Bch. (cabbage or 

 radish root maggot) in Indiana [cf. R.A.E., A, iv, 463], together 

 with the experiments with corrosive subhmate undertaken in 1921 

 are described. Of corrosive sublimate | oz. should be dissolved 

 in 1 U.S. pint hot water, and then diluted to 5 U.S. gals. ; this 

 will suffice for two or three hundred plants. Early cabbages should 

 be treated as soon as the eggs are observed, and again twelve days later, 

 pouring about half a teacup at the base of each plant. Late cabbage 

 in seed-beds can be treated in the same way except that the solution 

 should be poured along the rows in a stream. Radishes require about 

 1 gal. to each 35 ft. of row, and one application is usually sufficient 

 if applied after they are above the ground. Dusting with a table- 

 spoonful of 1 oz. corrosive sublimate mixed with 6 lb. hydrated lime 

 or gypsum at the base of each plant is recommended, but should not 

 be used on seed beds, as it may scorch the very small plants. The 

 demonstrations showed that no effective control is apparently possible 

 when the larvae are one-third grown. 



Morrill (A. W.). The Citrus Thrips. — Arizona Univ. Coll. Agric, 

 Tucson, Circ. 23, August 1918, 5 pp., 2 figs. [Received 11th 

 February 1922.] 



Scirtothrips citri, Moul. (citrus thrips) causes characteristic scarring 

 of citrus fruit, which is the most important feature of damage to old, 

 bearing trees. Nursery stock and young planted trees are frequently 

 severely injured by the checking and stunting of their growth. The 

 results of extensive examinations a few years ago in the Salt River 

 Valley of the fruit in different groves before and after picking are 

 recorded. In the field it was found that the injury to navel oranges 

 ranged from none to about 60 per cent, scarred sufficiently to affect 

 the market value. There is not only a reduction in the amount of the 

 fruit that can be sold as first grade, but a reduction in the value 

 of that passed as first. Contrary to general opinion, the pomelo, or 

 grapefruit, is also subject to much damage by this thrips. 



Excessive injury may be prevented by spraying with lime-sulphur. 

 The author secured fully as good results with lime-sulphur 36° Be. 

 diluted at the rate of 1 : 85 parts water as with hme-sulphur (1 : 85) 

 and tobacco extract (40 per cent, nicotine, 1:1,800). For lime- 

 sulphur solution testing 33° (the usual strength of the commercial 

 product), the dilution should be at the rate of 1 :78 parts of water. 

 Four applications in the season are recommended, the first after most 

 of the petals have fallen, the second 10-14 days later, the third 

 3-4 weeks after the second, and the fourth in August or September 

 for the protection of late growths of fohage. This schedule is only 



