325 



plant-eating caterpillars, but is also poisonous to cattle. Copper aceto- 

 arsenite (Paris green) is prepared by dissolving 4 lb. of white arsenic 

 in 5 galls, water and mixing with 5 lb. verdigris in 5 galls, water. The 

 mixture is boiled for an hour and a little acetic acid added. The spray 

 is made of 1 gal. of this solution to 150-200 gals, water to which has 

 been added 2 or 3 lb. lime. This compound is not satisfactory as a 

 dusting powder. The spray fluid has to be stirred continually and 

 has the further disadvantage of usually containing some soluble 

 arsenic and copper both of which scorch the leaves. It is effective 

 against all biting insects, but as it is fatal to man and cattle, cannot 

 be used upon fodder, fruit or vegetables. Copper arsenite (Scheele's 

 green) is applicable to the same conditions as Paris green and is equally 

 efficacious. Lead arsenate is more satisfactory in that it has no 

 scorching action on the leaves and is very adhesive. It is obtained 

 commercially in the form of paste ; Ih lb. of paste to 60-100 gals, 

 water, with 5 to 10 lb. slaked lime forms a suitable mixture. Lead 

 arsenate is less poisonous to man and cattle than Paris green. At the 

 rate of 1 lb. to 100 gals, water with 3 to 5 lb. lime and 5 lb. low-grade 

 sugar, it is effective as an insect poison and is comparatively safe for 

 cattle. A spray containing 1 lb. arsenate in 60 gals, water is most 

 often used ; if the foliage is thick and leathery, the strength should be 

 increased to 1 lb. in 25-30 gals. For skipper caterpillars on coconuts 

 and bananas, a wash containing 1| lb. paste to 60 gals, water with 

 the addition of 5 to 10 lb. lime per 100 gals, is recommended. 



Watson (J. R.). Report of Entomologist. — Rept. Florida Univ. Agric. 

 Exp. Sta., 30th June 1913, GcmiesvUle, June 1914, pp. liv Ixxi, 

 4 figs. [Received 15th March 1915.] 



Spraying experiments with Microcera against white-fly were carried 

 out from January 1912, for a whole year. The spores obtained from 

 cultures on sweet potatoes were sprayed on to the young trees, and 

 whole twigs were dipped into water containing the spores. Except 

 in unfavourable weather — i.e., in dry periods — spraying with a 

 suspension of Microcera spores caused a marked rise in the natural 

 mortality of the larvae, though the effect was only temporary . Microcera 

 is less virulent than either Aschersonia or Aegerita, but acts more 

 (|uickly ; therefore, in spraying with either of the latter it is advisable 

 to add Microcera and cultivations of Microcera on potato are to be 

 preferred to larvae as a medium. A detailed account of the whitefiy 

 in citrus groves and the effect of spraying on them is given. Aleurodes 

 howardi (woolly whitefly) was discovered in Arcadia, in December 1912, 

 and from this point has spread rapidly eastward as far as Orlando. 

 The rate of increase, however, is very variable in different districts. 

 Honeydew is secreted more abundantly by this species than by A . citri, 

 but the ordinary sooty mould does not develop so well in this case. 

 Other fungi — e.g., Cladosporinm thrive rapidly. The adults are more 

 sluggish than those of A. citri, but are more liable to be carried long 

 distances on the clothing of travellers. The life-history is not fully 

 known ; in Lakeland and Tampa adults were numerous on 14th May ; 

 a week later most of them had disappeared, though some were still 

 seen by the middle of June. The food preferences for different varieticB 

 of citTUs are the reverse of those of A. citri, in which grape-fruit is the 



