PINE NEEDLE-CAST. 



465 



c. Proteclive Rules. 



i. Careful choice of suitable localities for spruce. 



ii. Carry out early and strong thinnings, especially on 

 trees affected by the disease, and promi)tly remove the latter 

 from the forest. 



*19. Lophodennium Pinastri, Sclirad. 



(Pine Needle-cast.) 



a. D/>scn'/)tioH and Lifc-histnrij. 



On the primordial needles of young Scots pines, solitary 

 brown spots may appear in July or 

 later on in the year, and if the affected 

 needles are examined microscopically, 

 the mycelium of Lophodcrminni (Hys- 

 teriiim) Pinastri, Schrad., will be found 

 in them. Black spermagonia subse- 

 quently appear before winter, but their 

 spores do not germinate, as ascocarps do 

 not develop till the second year after 

 infection. As a rule the diseased pri- 

 mordial needles die in the spring, with- 

 out falhng from the plants, and older 

 needles frequently turn completely brown 

 in March and April and fall off, owing 

 to the formation of cork at their base. 

 This sudden shedding of pine needles is 

 the characteristic of the disease so widely 

 spread in Germany and termed Schiitte, 

 or needle-cast, which may, however, be 

 due to other causes besides the fungus, 

 as explained on p. 685. If, owing to a 

 mild, wet winter and spring, the black 

 sporocarps should burst, which only 

 happens when they are exposed to much moisture, the spores 

 issue from them and infect fresh plants. This, however, 

 frequently happens only after the needles have fallen. Dry 

 summers and cold winters therefore impede the spread of the 

 fungus, which is frequently only saprophytic on old, dying 



F.P. H H 



Fig. 226.— (a) Yearling 

 Scots pine needles 

 attacked by Pine 

 needle -cast, the base 

 green. (/y) Dead two 

 years old needles. Ripe 

 apothecia (x) and empty 

 jytjcnidia (y), in April. 

 After Hartig. 



