202 



JOURNAL OF ECONOMIC ENTOMOLOGY 



[Vol. 5 



fungicide immensely increased the number of scales present. Hereto- 

 fore there has been no careful quantitative data as to what extent this 

 is true, but during the past summer such experiments were carried 

 on by Professor Fawcett and the results are given in the accompany- 

 ing table. Ten representative oranges and fifty representative leaves 

 were taken from each plot and counts (or estimates in the case of those 

 oranges from the Bordeaux plots) were made of the scales and whitefly 

 on each. The figures in the table are the averages. These trees 

 were sprayed in June, in July, and on August 31. 



TABLE I 



The Bordeaux mixture by killing the parasitic fungi allows the un- 

 hindered multiplication of the scales and gives us some idea as to what 

 they would do were they not naturally held in check by the fungi. 

 The Bordeaux column, then, and not the unsprayed trees should be re- 

 garded as the "check" in considering the efficiency of the fungi. Even 

 then, however, we do not get a true picture of the importance of the 

 fungi as these trees were covered with the fungicide for only a few 

 months, whereas it should have been extended over several years to 

 give us a true check. Also they were surrounded on all sides by 

 fungous-covered trees which reinfected them before the last count. 

 Nevertheless this gives us some idea of the role that these parasitic 

 fungi naturally play in the citrus groves of Florida and demonstrate 

 the truth of the statement of Doctor Berger that "It is the fungi that 

 keep the grower in business." 



Whitefly. The chief fungi concerned in keeping in check Aleurodes 

 citri R & H and A. nuhifera Berger are, in the order of their importance, 

 the Red Aschersonia (A. aleyrodis), the Brown Fungus (Aegeritia 

 webberii), the Cinnamon {Verticillium heterocladum) , the White Fringe 

 {Microcera sp.), and the Yellow Aschersonia {A. flavo-citrina) on 

 Aleurodes nubifera only. The first three and the last attract the larva 

 and pupa, the fourth, all stages. This is also a complete saprophyte, 

 developing in immense numbers on the bodies of insects killed by 

 fumigation. They are all partial saproph^iies since the major part 

 of their development occurs after the insect is dead and they can all 

 be raised on artificial media. 



What was said about the efficiency of the fungi in keeping down the 



