22 NATURAL CONTEOL OF WHITE FLIES IN FLORIDA. 



hyphse or mycelium. This circle becomes opaque and whitish, 

 presenting a very characteristic appearance. Shortly after this 

 the hyphae burst out around the edge of the larva, forming a dense 

 marginal fringe. This may form all around the larva at about the 

 same time, or may develop at one portion of the margin sooner than 

 at the others. The body of the larva at this time is plainly visible, 

 but it is opaque and yellowish throughout. Death usually ensues, 

 it is believed, before the hyphse burst out. The fungus does not 

 spread over the leaf to any great extent, but grows upward in a mass, 

 gradually spreading over the larva. It is not uncommon to find the 

 perithecia, with their bright coral-red masses of sporules, formed in a 

 circle around the edge of the larva while it is yet visible. As the 

 Aschersonia develops, the hyphee spread over the larva, forming a 

 dense, compact stroma, which ultimately entirely envelops the 

 larva. The stroma in this stage is thin and disklike, the fructifica- 

 tions being usually borne in a circle near the edge. The hymenium 

 at this time is spread out on the surface of the stroma, or but slightly 

 sunken, the sporules projecting in a conical coral-red or rufous mass. 

 As the fungus develops the stroma becomes thickened and hemi- 

 spherical and the hymenium gradually becomes immersed. The 

 hyphae which make up the main mass of the stroma are from 3.5 to 

 7.5 micromillimeters in diameter. Within the body of the insect 

 and near the perithecia they are somewhat smaller. 



Data collected in connection with experimental work in the field 

 have shown that well-developed pustules can mature within 15 days 

 after artificial spreading of the infection. Ten shoots on the outside 

 of a tree which were sprayed on June 25, 1909, had developed by 

 July 10 numerous well-developed pustules (red Aschersonia). Check 

 shoots produced no fungus growth. The range in temperature 

 during this period was from 70° to 95° F. (average daily mean, 80.5° 

 F.) and frequent showers fell. Fungus introduced by spraying on 

 July 27, 1907, had produced pustules by August 17, or 21 days later. 

 During this period the temperature ranged from 70° to 98° F. 

 (average daily mean for period 80.8° F.), with numerous showers. 

 In both of these instances no earlier examinations were made. In 

 another instance a larva of A. dtri, noted to have died on October 15, 

 1908, began to develop a whitish appearance on October 23, or 8 

 days later, and while the fungous growth was daily observed the 

 characteristic reddish color of the spore masses of red Aschersonia 

 did not appear until November 4, or 12 days after the fungus first 

 began to be visible to the eye and 20 days after the larva was recorded 

 as having died. During the 20-day period the temperature ranged 

 from 45° to 85° F. (with an average daily mean of 70.4° F.) and there 

 was no rain. The average daily mean humidity for the three periods 

 was 92.3, 89, and 90 per cent, respectively. 



