DYING OF YOUNG PINES IN CIRCLES ABOUT ANTHILLS 765 



7. If ants do not carry the fungus, how is it carried? 



8. Is infection merely secondary, following mechanical injury {e.'g.,. 

 by ants) ? 



9. Are trees weakened by the presence of ants {e. g., mechanical 

 injury to the roots, by root injury due to associates of ants (aphids), 

 chemical injury, modification of composition of soil water) ? 



10. If infestation is secondary, what is the primary cause? 



R. Hartig^ notes that it seems unnecessary that there be a mechan- 

 ical injury to the bark of Abies before Phoma abietina Hartig can gain 

 an entrance, that twigs are attacked, and that girdling can occur. Ac- 

 cording to Engler and Prantl,^ there are more than 1,100 species of 

 Phoma (Fr.) Desm (= Clisosporium Bon, Sphceropsis Lev. pr. p., 

 Geridajacta Preuss pr. p., Coniothyrium aut, pr. p., Sporonema pr. p.) ; 

 P. Pini (Desm) Sacc occurs on fallen leaves of Picea excelsa in 

 France ; P. pitya Sacc on Pscudotsuga and Pinus sylvestris and Pinus 

 strobus, Phoma, occurs in general on all parts of the plant except the 

 leaves, but also on the leaves of ConifercE and Cryptogams. Of Pusi- 

 cocciim Corda there are more than 40 species; F. abietinum (Hartig) 

 Prill, and Del. causes the Binschniinmgskrankheit of Abies. F. Pini 

 (Preuss) Sacc occurs on pine bark in Silesia.® Phoma and Fusicoccum 

 are both classed in the same general group :® 



Fungi imperfccti 



Sphceropsidales 



I. Sphcerioidacecc 



I. Hyalosporcs 

 2. Phoma 

 29. Fusicoccum. 



The Fungi imperfecti are spread by exogenously produced spores, 

 Conidia. Underwood^" notes Phoma as saprophytic. 



At Portland ten anthills were observed in the 1908 plantations. Of 

 these, six were surrounded by the blanks, while about the other four 

 all the trees were living. 



The disease as observed here was characterized on the living trees by 

 elliptical reddish sunken areas (sometimes confluent), with a lenticel 

 as center (fig. i). Toward the ground these areas appear to be con- 



'' Loc. cit. 



• Pflanzenfamilien I i**, 1900. 



* Engler and Prantl : Loc. cit. 



" Underwood, L. M. : "Moulds, mildews, and mushrooms." 1899. 



