21 l-r.\(,i I'AKASITIC UPON ALEYRODES CITRI. 



cose agar were poured. A moistened needle was drawn over the upright 

 brush of conidiophores and washed into a little bouillon in a test-tube. In- 

 oculations were made from this with a platinum loop, nine loops being 

 transferred to A, and nine from A to B. 



On November 20 (8 days), 120 pure white mycelia appeared in A and 4 

 in 1>. :> to 4 mm. in diameter, with reddish brown center and a brush of up- 

 ward growing white conidiophores. On December 5 (23 days), the mycelia 

 in B were 25 mm. in diameter and reddish brown. On December 12 (32 

 days), the mycelia in B were 30 to 35 mm., and cinnamon-colored almost 

 to the edges. By this time a pustule was formed composed of closely inter- 

 woven hyphae and closely resembling the pustules upon larvae of Ale\rodes 

 citri (Plate V, Fig. 34)." 



The fungus was transferred to test-tubes of sterilized Irish potato, 

 sweet potato, rice, white cornmeal, stems of canna and of caladium, and 

 bread ; on all of which the fungus grew to some extent. It grew best, how- 

 ever, on sweet potato and bread, over the entire surface of which it formed 

 a felted cinnamon-colored stroma (Plate V, Figs, 32, 33). On rice the 

 color was that of ocher, and on caladium stems it was brick-red. On the 

 other media the color was nearly that of the growth on 5 per cent, glucose 

 agar. 



The growth on sweet potato plugs was recorded as follows : On Novem- 

 ber 22. 1 !><<;, conidia from cultures made November 12, were rubbed on the 

 surface of the potato. On December 5 (13 days), a brown colored growth 

 had formed over the surface of potato. By December 12 (20 days), the 

 entire surface was yellowish brown. On January 15, 1907 (39 days), the 

 entire surface was covered over with a thick cinnamon-colored mat of 

 fungus. 



(.KR MI. NATION OF CONIDIA. 



Conidia were placed in distilled water in hanging drops. It was found 

 that they germinated much more rapidly than did the conidia of Ascher- 

 sonia. In distilled water, in 24 hours, conidia had just begun to elongate; 

 in 18 hours a few spores were found with short hyphal tubes. In bouillon, 

 in 24 hours a slight germination took place, the hyphal tubes becoming as 

 long as the spore: in :> days, the hyphae were 120 to 200 microns long and 

 1 to \ l /2 microns wide, and branched once or twice. 



In ~> per cent, glucose, in 24 hours, the tube had extended one to two 

 times the length of the spore, and in three days, the growth had proceeded 

 farther than those in distilled water. 



When germinating, the spores first swelled, elongated, and then sent out 

 a hyphal tube from one or both ends. 



IM IATION OF LARVAE OF ALEYRODES CITRI. 



( )n December (\, llinii. small badly infested orange trees which had pre- 

 viously been in the greenhouse, were covered wiih large belljars. Conidia 

 from a petri dish culture poured Xovember 12, I'.MM; \->\ days old), were 

 shaken up in sterile water, and this was spraved on to the plants with a 

 small atomizer. In :>:> days several leaves were found with stromata in a 

 spore-bearing condition, identical with those from which the culture had 

 originally been obtained. These had evidently developed sooner than 35 

 lays, and had been overlooked. Thev became powdery in appearance and 

 in all particulars were like the natural pustules. 



