66 REPORT OF SCHIMMEL § Co. OCTOBER 1915. 
The disease is known as “canker lemon spot”, ,,leaf spot”, “wither tip”, or “anthrac- 
nose”. Another danger for lemon trees is Cladosporium citri, B. et F., called “lemon 
scab”. It roughens the leaves by raised corky growths on the upper surface. When 
the fruit is attacked its market value is lowered. Capnodium citricolum, M’Alpine 
_ (Perisporiaceae), covers leaves, stems and fruits with a sooty mould. It grows on the 
honey dew exuded by insects, the best remedy being to destroy the insects by spraying. 
The “lemon fruit rot” is due to various Penicilliwm species, especially P. italicwm, 
Wehmer, and P. glaucwm, Link. (Aspergillaceae). But these are saprophytic, and the 
fruit rarely rots, unless the spores get into it where the skin or cuticle has been 
broken by careless handling. 
The “brown fruit rot”, caused by Pithyacistis citrophora, R. E. Smith, has brought 
about severe losses in California. It first appears as a brownish or purplish dis- 
colouration of the rind and is characterized by a peculiar odour, which attracts small 
flies; it spreads readily from fruit to fruit. Remedies suggested are formalin, sbi 
F raiaripasiate or copper sulphate. 
The causes of the disease called “dieback”, characterized by the dying-back of the 
leaf tips, rusty spots on the leaves and twigs, the formation of gum and the falling 
of the small fruit, is not known as yet exactly. It has been suggested that Agaricus 
citrt and A. hesperidum have some connection with the formation of the gum, these 
fungi being saprophytic on decaying roots. 
Polyporus obliquus and P. fumosus have been found to attack the roots through 
wounds, and kill the trees in from three to five years. These fungi and also Rhizoctonia 
violacea are said to be destructive in Malta to citrus trees grown in clay soil on low 
ground. In order to sterilize soil containing Rhizoctonia, carbolic acid is recommended. 
A disease known as the “black rot” has been reported from South Africa, due to 
Diplodia natalensis, appearing first as a translucency of the rind at the stalk end of 
the fruit, the tissue rapidly softening and becoming brown, and the colour spreading 
over the whole fruit, which becomes ultimately black, with a shrivelled surface. 
Phytophthora Syringae, Kleb. (Peronosporaceae) lives aS a parasite on lilac and 
destroys its buds and twigs. Phyllosticta Syringae, Westend. (Sphaerioidaceae), likewise 
becomes injurious on lilac. 
Mignonette has to suffer from Cercospora Resedae, Fuck. (Dematiaceae), the leaves 
showing brown spots. Spraying with dilute Bordeaux mixture, as soon as the disease 
is noticed, is recommended. . 
Narcissus leaves are attacked by Puccinia Schroeteri. The bulbs of non-odorous. 
narcissus species show to a serious extent a disease caused by Fusarium bulbigenum, 
Cooke et Mass. (Tuberculariaceae), the presence of which is first indicated by small 
yellowish spots on the leaves. The mycelium of the fungus passes down the tissue 
of the leaf into the basal portion from which the scales arise, and the whole of the 
scales are attacked. The bulbs then become attacked by saprophytic fungi, such as 
Penicillium. 
Two fungus diseases have been reported as attacking the nutmeg tree. One attacking 
the bark has been named Eutypa erumpens, Massee (Valsaceae), and has occurred in 
Barbados, Grenada and Trinidad. The other, Corticiwm javanicum, Zimm., has been 
reported from Java. It attacks the roots. 
The ‘gum disease’, “mal di gomma”, of the orange tree is perhaps due to 
Fusarium limonis, Briozi, or Agaricus citri, but it may be that it is due to bacteria. 
Cladosporium herbarum, Lk., var. citricolum, Lk., affects the bark of the tree as well as 
the rind of the orange. It has been identified with the conidial form of Sphaerella 
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