860 EXPERIMENT STATION RECOED. 



of the vine; the second part (pp. 87-417) with studies of the grapevine 

 phylloxera (Phylloxera vastctrix) with observations comparing it with other 

 species. A bibliography of 13 pages follows. 



A second paper, by Anna Foa (pp. I-LXXV), is devoted to the biology of 

 the grapevine phylloxera. 



Natural control of white flies in Florida, A. W. Morrill and E. A. Back 

 ([/. H. Dcpt. A(jr., Bur. Ent. Bid. 102, pp. 78, pis. 9, fig. J),— This is a detailed 

 report of investigations commenced in 190f) and extending over a period of 4 

 years. The subject is taken up under the headings of i^arasitic and predatory 

 enemies of white flies ; snails that feed on sooty mold ; climatic conditions ; un- 

 explained mortality ; dropping from leaves ; mortality due to overcrowding ; 

 effect of curling and dropping of leaves from drought; bacterial diseases; and 

 fungus diseases. 



" No true parasites of these species of white flies are known to exist in this 

 country and their numerous native predatory enemies are usually of no material 

 assistance in their control. Two factors of natural control, overcrowding and 

 unexplained mortality, have heretofore not been recognized or have been con- 

 fused with the results of attempts at artificial control or with the effects of 

 fungus diseases. The 2 factors named are in effect a reaction from excessive 

 infestation. Bacterial diseases of the white flies are at present unknown but 

 it is not improbable that they are the leading cause of mortality so far un- 

 explained. . . . 



"Aside from unexplained mortality, fungus diseases are the most important 

 agents of natural control. The brown fungus (JEgerita wehheri) and the red 

 Aschersonia {Aschersonia alcyrodis) are, in the order named, the most effective 

 parasites of the citrus white fly. The yellow Aschersonia (A. flavo-citrina) is 

 the most effective parasite of the cloudy-winged white fly. The cinnamon 

 fungus {Verticillium hcterocladum) and the Sporotrichum fungus (Sporotri- 

 chum sp.) are of comparatively little importance. The red-headed scale fungus 

 {SphwroiitUhe coccophila) is rarely parasitic upon white flies, while the white 

 fringe fungus ( Microcera sp.) is with little doubt normally saprophytic. The 

 fungus parasites thrive only under suitable weather conditions during a period 

 of about 3 months each year, generally speaking the summer months in the 

 case of the 2 Aschersonias and the fall months in the case of the brown fungus. 

 Their efficacy in destroying white flies under natural conditions is dependent 

 upon the abundance of the insects; a period of excessive abundance always 

 precedes effective temporary control. . . . Under natural conditions, without 

 artificial assistance in spreading, the fungi have ordinarily, in favored locali- 

 ties, controlled the white fly to the extent of about one-third of a complete 

 remedy through a series of years. . . . 



" The authors conclude that there are at present no elements of natural con- 

 trol herein dealt with which can be relied upon to give satisfactory results. 

 Under present conditions it is unquestionably more profitable to depend upon 

 artificial remedies." 



White fly parasites and their attempted introduction into Florida, R. S. 

 W'OGLUM (Ila. Grower, 6 (1912). Xos. 9. p. 3; 10, p. 3). — An address on the 

 attempted introduction of insect enemies of the white fly from India, a brief 

 account of which by L. O. Howard has been previously noted (E. S. R., 25, p. 

 661). 



Some scale insects of Mississippi, with notes on certain species from Texas, 

 G. W. Herrick (Mississippi Sta. Tech. Bui. 2, pp. 3-78, figs. 96).— This bulletin 

 discusses the collection and preservation of scale insects, the literature, and the 

 technique to be made use of in preparing them for study, and gives a list of 40 

 species known to occur in Mississippi, 6 additional from Texas, and 1 from 



