. Cottony rot of lemons in California. Fij .—Eureka lemon tree in nurseryaffected with cottony rot. 246 UNIVERSITY OF CALIFORNIA—EXPERIMENT STATION has come, they revive and become active. The sclerotia may then sendout a fresh growth of mycelium, the vegetative stage, which couldeasily infect dead organic matter or the weaker plant growth of weeds. Pig. 7.—Cottony rot affecting the twigs of a Eureka lemon tree, (a) Massesof gum produced by the fungus, (b) Sclerotia of the fungus distinguished fromthe gum globules by more spherical shape, (c) Fibrous condition of infected bark. or cover crops.
. Cottony rot of lemons in California. Fij .—Eureka lemon tree in nurseryaffected with cottony rot. 246 UNIVERSITY OF CALIFORNIA—EXPERIMENT STATION has come, they revive and become active. The sclerotia may then sendout a fresh growth of mycelium, the vegetative stage, which couldeasily infect dead organic matter or the weaker plant growth of weeds. Pig. 7.—Cottony rot affecting the twigs of a Eureka lemon tree, (a) Massesof gum produced by the fungus, (b) Sclerotia of the fungus distinguished fromthe gum globules by more spherical shape, (c) Fibrous condition of infected bark. or cover crops. Here after a time new sclerotia are again formed.(3) From the sclerotia in the soil the spore stage is formed underthe cover crops in the lemon orchards. This last is accomplished bysending out a growth which eventually develops into a small funnel- COTTONY ROT OF LEMONS IN CALIFORNIA 247 shaped, cup-like disk, technically called an apothecium (Fig. 2). Inthe flesh of the apothecia are produced the spores. These are formedin rather long cylindrical sacks or asci (Fig. 3). Hence the spores arecalled ascospores. Both the spores and asci are microscopic. Thespores are easily scattered by the wind. The fungus also has thepower to force out or discharge these spores, and they can often beobserved leaving the apothecium as small clouds of dust.
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