Bor ER .-GA RIN AAT OCNSSe- EF OUR 1943— GlgGel 
TREATMENT OF INSECTS AND DISEASES (Continued) 
bark is seen to be yellowish or reddish brown extending up and down following the sap channel. 
If the branch is removed before the disease has progressed into the stem, the plant may possibly 
be saved. Later the brown color expands into the inner tissue of the stem and into the outer bark 
from the conductive tissue. When the stem is invaded, the branches on the infected side die, and 
ultimately the entire plant succumbs. The inside tissue of an invaded stem is dry and ‘of a dull 
brown color, similar in appearance to dead timber. As the infection is usually aerial, soil sterilization 
is of little value, and there is no known spray which will prevent or cure it. Sterilizing benches, 
flats, soil and sand are sanitary methods which are helpful, but do not expect to control Fusarium 
Branch Rot in this manner. Warm, moist conditions are favorable for the growth of the disease. 
Avoid excessive and overhead watering and injuries to plants. Provide plenty of air, and run houses 
cool. Discard those varieties that are particularly susceptible. 
ALTERNARIA BLIGHT § (Alternaria dianthi) 
This disease is known as spot, blight or branch rot. Purple spots appear on leaves and 
flower parts, later browning and blighting the parts. Under moist conditions the blighted parts 
become overgrown with blackish or sooty masses of fungus. After benching, the fungus causes 
a prevalent branch rot centering at the nodes. Here the fungus causes dark colored spots or cankers 
which partially or completely girdle the branch. Ultimately the rot progresses deeper into the 
tissue, and the portion of the branch above wilts. The color of the invaded tissue is dark brown, 
almost black, and the color may extend from the bark to the wood. The discoloration extends 
inward from the outside, and does not follow the conductive tissue as does Fusarium. Infection 
takes place without the plant having first been injured, and almost always occurs in the field. Before 
branches wilt, the leaves are streaked or marked with whitish or light green areas. Certain varieties 
are more susceptible to the disease than others. Inside culture will usually eliminate Alternaria. 
Spraying with Bordeaux weekly from the time that plants go to the field until they are benched will 
form a chemical barrier between the plant and the fungus which is very effective. Alternaria is 
not carried in the cuttings, and any variety is likely to be attacked. 
BACTERIAL LEAF SPOT (Phytomonas Woodsit) 
This disease is so rare in many sections that growers are likely to confuse it with alternaria 
blight or fairy ring, and therein lies its greatest danger. It is a foliage disease caused by a bacteria 
or microbe which progresses from the lower leaves upward, attacking the stem and bud only in 
very severe cases. If not checked, the plant becomes defoliated and will die. In any case, the 
plants will be checked and production arrested. The disease occurs only in the presence of injuries, 
but spiders, thrips, aphids, etc., will provide sufficient injury for the bacteria to gain entrance. It 
is, therefore, of vital importance that plants be kept free of insects. The development of the disease 
is slow at temperatures of 60 degrees or less, and very rapid at higher temperatures. The trouble 
is first indicated by the presence of small, oval spots of pale brown color. These spots are usually 
sunken, and soon become yellow with a dark green or purple margin. These spots may include 
the entire breadth of the Jeaf, and where spots are numerous, they have a tendency to grow 
together. Several spots ultimately cause the death of the leaf, in which case the leaf turns a yellow 
straw color, withers and dies, the spots retain a rusty brown color. Greenhouses should be kept 
cool, dry and well ventilated. There must be no overhead watering of any kind. Fortunately the 
disease may be cured or prevented by use of a spray consisting of 3 pounds of zinc sulfate, ly, 
‘pounds alum, 4 pounds hydrated lime, and a good spreader to 50 gallons of water. Dusting with 
fine sulphur is a further precaution which may be taken. 
RUST icge: (Uromyces caryophyllinus) 
Sulphur is the most effective preventative and cure for rust. Use a fine dusting sulphur, and 
apply it with a good blower. Use it on young plants as soon as the first trace of rust appears, and 
apply on bright, warm, days. Sulphur may safely be used once a week or oftener. In light soils 
it may cause a slight acid reaction, but this is easily overcome. In the field where dusting is imprac- 
tical, lime-sulfur may be sprayed. Bordeaux or other copper sprays have very little effect on rust. 
The disease is so easily prevented or cleaned up that there is no excuse for a grower permitting his 
plants to become damaged by it. Keep plants dry, provide plenty of air, and run houses cool. 
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