SUMMARY. 37 



SUMMARY. 



1. Entomogenous species of fungi representing many different genera 

 have been described in the past hundred or more years. 



2. These have not, until recent times, been studied from an economic 

 standpoint. The greatest success in the use of fungi to combat insect 

 pests seems to have been attained in Florida, where proper conditions of 

 temperature and moisture are present. 



3. Aleyrodes citri R. & H., known since 1885 as a pest to citrus trees in 

 Florida, has spread to many citrus districts since that time, doing much 

 damage chiefly by creating conditions favorable to the growth of Meliola. 



4. A study of the fungi parasitic upon Aleyrodes citri shows that there 

 are at least six species, five of which have been grown upon culture media 

 in the laboratory. 



5. Aschersonia ale\rodis Webber is the most widely distributed fungus 

 parasite of Aleyrodes citri. It is easily isolated and grown in pure cultures 

 in 5 to 10 per cent, glucose agar medium, maturing a stroma in 30 to 40 

 days. 



6. Healthy larvae of Aleyrodes citri may be infected from cultures of 

 this fungus by spraying a mixture of conidia in water on trees infested with 

 Aleyrodes citri. 



7. Aschersonia flai'o-citrina P. Henn., which was recently found in 

 eastern Florida, is also an important parasite of Aleyrodes citri. Its growth 

 on culture media is the same as that of A. aleyrodis. 



8. Conidia of both of the Aschersonias germinated best in a 5 to 10 per 

 cent, solution of glucose in water. Percentages of sugar above or below 

 this retarded germination. Conidia from stromata dried in the laboratory 

 for more than 28 days failed to germinate. 



9. Verticillinni heterocladnni Penz. has been recently shown to occur 

 parasitically upon Aleyrodes citri. It has also been observed on a number 

 of other insects. Cultures and inoculation experiments show that this 

 fungus is distinct from the "Brown fungus", which it somewhat resembles in 

 general appearance, and with which it is frequently found associated. 



10. The growth of this fungus in cultures is much more rapid than that 

 of the two species of Aschersonia described. 



11. Sphaerostilbe coccophila, known since 1848, is world-wide in dis- 

 tribution, and has been reported on no less than fifteen species of scale 

 insects, in addition to being found on Aleyrodes citri. 



12. Sphaerostilbe coccophila has been used in Florida as an effective 

 parasite in controlling the San Jose scale and other scale insects. In more 

 northern States it has not proved to be effective. It is possibly a weak 

 parasite of Aleyrodes citri. 



13. Microcera sp., recently discovered, has been found in a number of 

 places in Florida attacking larvae of Aleyrodes citri. Abundant cultures of 



