300 



leaves. Lead arsenate dust had much the same effect ; ziuc arsenite 

 (2 lb. to 50 U.S. gals, water with 2 lb. stone lime) was less adhesive ; 

 sodium arsenite killed or damaged the plants. A spray of Blackleaf 40 

 (1 pint to 100 U.S. gals, water with 4 lb. soap) killed very young larvae 

 when they were hit by it, but had no effect on older stages. Lead 

 arsenate and lime- sulphur combined cleared the plants for two weeks, 

 after which they became re-infested. A fine spray with an angle 

 nozzle is recommended. 



In Colorado, only one generation in a year is reported. 



Paddock (F. B.). The Turnip Louse.— Texas Agric. Expt. Sta., Austin, 

 Bull. no. 180, October 1915, 77 pp., 5 plates, 10 figs. [Received 

 16th May 1918.] 



Much of the information contained in this bulletin on Aphis j3seudo- 

 hrassicae (turnip aphis) has previously been pubhshed elsewhere [see 

 this Review, Ser. A, iv, p. 187]. 



Paddock (F. B.). The Harlequin Cabbage-Bug. — Texas Agric. Expt, 

 Sta., Austin, Bull. no. 179, October 1915, 9 pp., 1 fig. [Received 

 16th May 1918]. 



Murgantia histrionica, Hahn (harlequin cabbage-bug) is found in 

 almost every field and garden in Texas where cabbages are grown, 

 and it also attacks kale, cauliflower, turnip, radish, mustard, rape, 

 and other plants of the mustard family. Entire fields of cabbage 

 may be destroyed in a few days by a severe infestation. The life- 

 history of M. histrionica is not fully known. Adults hibernate in 

 any sheltered spot in or near the infested fields, though in the warmer 

 sections of the State the insects may be found feeding in the fields 

 during the greater part of the winter. The adults emerge from their 

 winter quarters in old crop or weed rubbish early in the spring, some- 

 times as early as 1st March. The first brood is usually found on 

 wild mustard or closely related plants, and oviposition occurs on these 

 plants about 10 days later. These eggs hatch in 4 to 8 days, the 

 nymphs attacking cabbage as soon as it is available. The nymphs 

 carniot fly and their power of migration is therefore limited. It is 

 probable that in the northern part of the State there are two broods 

 in a year and perhaps a partial third ; in the central sections of the 

 State there are perhaps three full broods and in the northern sections 

 there may be four generations in a year. Adults that do not lay their 

 eggs before 1st September live through the winter and oviposit in 

 the following spring. With the exception of one parasite of the egg, 

 M. histrionica has very few natural enemies. 



Preventive and remedial measures have been previously dealt with 

 [see this Review, Ser. A, v, pp. 388, 529]. Mustard is recommended 

 as the best trap-crop for this bug. 



Merrill (J."H.). Spraying Fruit Trees. — Kansas State Agric. Expt. 

 Sta., Manhattan, Circ. no. 66, April 1918, 8 pp. 



Instructions are given for making lime-sulphur sprays, self-boiled 

 lime-sulphur, dry lime-sulphur, and Bordeaux mixture, with recom- 

 mendations for applying dormant sprays. Spray schedules are given 

 for apple, pear, peach and plum trees in a series of tables. 



