SCl.EROTINIA WITH BOTRYTIS-CONIDIA. 



269 



Sclerotia, along with Botrytis-conidia,, have been found fre- 

 quently on diseased geraniums. 



During the summer of 1894 a withering of twigs of Prunus 

 triloba occurred in several gardens at Munich (Fig. 141). A 

 mycelium was found in the bark, leaf-petioles, and young 

 ovaries, while Botrytis-coxAdxa, were 

 developed on the dead parts. 

 With these I successfully infected 

 young needles and twigs of spruce. 

 Sclerotia were also formed on plum- 

 gelatine in fourteen days. The 

 parasite in this case had killed old 

 twigs of Prunus, and also infected 

 twigs of Conifers. 



Botrytis Douglasii is a parasite 

 which 1 studied some time ago on 

 account of its presence along with 

 a disease on the Douglas fir (Pseu- 

 dotsuga Douglasii)?' I have since 

 had reason to believe that it is 

 allied to some form of selerotium 

 like that just considered, and my 

 view is supported by Behrens.^ 

 The disease as seen in various 

 parts of Germany is characterized 

 by withering, curling-up, and death 

 of young shoots towards the sum- 

 mits of young seedlings, and on the 

 lower twigs of older trees up to 

 about five feet above the ground. 

 In autumn, black sclerotia about 

 the size of pin heads, break through 

 the epidermis under the old bud- 

 scales, at the base of dead shoots, 

 and on the needles. In addition to these, smaller masses of 

 tangled hyphae are also formed. When sclerotia are placed 

 in a moist chamber, tufts of erect conidiophores arise, and 

 branch, forming numerous whorls of conidiophores, from which 



^ V. Tubeuf, Beitrage %. Kenntniss d. Baumkrankheiten, Berlin, 188S. 

 "Behrens, Zeitsch. f. Pflanztnkrankheiten, 1895. 



Fig. W!..— Botrytis 



lii on the 

 The young shoots and 

 apex of last year's shoot are dead. 

 (After Tubeuf.) 



Douglas Fir. 



