522 



Wilson (H. F.)- Common Insecticides ; their practical Value. — 



Wisconsm Univ. Agric. Eayt. Sta., Madison, Bull. 303. June 1919, 

 15 pp., 4 figs. 



Recent experiments carried out to ascertain the relative value of 

 various insecticides as such, and not as a control of any particular pest, 

 were made on the Colorado potato beetle [Leptinotarsa decemlinecda], 

 sawfly larvae on willows and blister beetles. Both under field and 

 laboratory conditions potato plants were chiefly used, as they are the 

 main crop in Wisconsin. 



Magnesium arsenate is mentioned as a new insecticide, but was not 

 included in these tests. 



Paris green apparently kills quickest, but it also has a tendency to 

 injure foliage and to settle quickly, and its adhesive qualities are not as 

 good as those of other insecticides. The amount recommmended is 

 1| to 2 lb. to 50 U.S. gals, of water. 



Hydrogen lead arsenate is the most desirable poison, as although it 

 does not kill quite as quickly as Paris green, it adheres and spreads 

 well on plants, causing practically no injury to the foliage. Basic 

 lead arsenate is the safer form to use on tender plants in certain 

 climates, but it is undesirable as a spray against insects that are not 

 quickly affected by poison. From 2 to 2i lb. of powder to 50 U.S. gals, 

 of water or Bordeaux mixture is recommended against L. decemlineata. 

 For codling moth [Cydia poDiooiella] and leaf-feeding insects 1 lb. to 

 the same amount of water may be used ; this proportion with the 

 addition of 1 lb. of laundry soap to increase its adhesiveness may also 

 be used against cabbage caterpillars and other chewing insects. 



Although zinc arsenite has a toxic power nearly equal to Paris green 

 it cannot be used for fruit trees owing to the damage caused to foliage, 

 but it is an efficient spray for L. decemlineafa. Used at a strength of 

 2 lb. of powder to 50 U.S. gals, of water or Bordeaux mixture 

 apparently no injury is caused to potato plants. 



Calcium arsenate remains in suspension nearly as well as hydrogen 

 lead arsenate and adheres equally well under favourable conditions. 

 In certain forms its killing power is also nearly as good as that of lead 

 arsenate and it may be used with safety if hydrated or unslaked lime 

 is added in equal amounts. These experiments also included the testing 

 of several proprietary insecticides and these are classified according 

 to their efficiency. 



Gentner (L. Ct.). Control the Cabbage Worm. — Wisconsin Agric. 

 Expt. Sta., Madison, Circ. 115, May 1919, 4 pp., 3 figs. [Received 

 9th October 1919.] 



The use of lead arsenate and calcium arsenate sprays against the 

 cabbage butterfly [Pieris rapae] is advocated [see this Review, Ser. A, 

 vi, p. 201]. When used in the form of a dust these poisons may be 

 diluted with from 5 to 10 parts by weight of air-slaked lime. 



Hinds (W. E.). Cotton Worm Control. — Alabama Agric. Expt. Sta., 

 Auburn, Circ. 42, August 1919, pp. 63-67, 2 plates. 



Attention is drawn to a probable outbreak of the cotton worm 

 [Alabatna argillacea] on cotton in Alabama during 1919. The remedial 

 measures advocated are the use of calcium arsenate and lead arsenate 



