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Pests and Their (Control 
FOLIAR NEMATODE 
The spread of this pest has been very rapid in recent years owing to the increased trade in chrysan- 
themums, and the ease with which the nematode is transported in plants and cuttings. Too few 
growers have become familiar with this pest and co nsequently no effort has been put forth to control it. 
SYMPTOMS. The leaves attacked become blotched, turn at first greenish-yellow, then brownish, later 
gray and finally black until the entire leaf dies and hangs down on the stem. Under conditions 
of high humidity, both in the open during a wet season and under glass owing to excessive water- 
ing, the spread of the pest may be extremely rapid. 
CONTROL. Sodium Selenate applied in liquid form to the soil at the rate of 4 gram per square 
foot of bed area will give good control. Dissolve 1 pound of sodium selenate into 4'/2 gallons 
of water, then take one quart of this stock solution and add to 25 gallons of water and this 
should be applied on 100 square feet of bench surface. One pound of sodium selenate will 
treat 1800 square feet. The safest method is to make 2 applications at the /e gram rate a week 
or so apart. P40 applied at the rate of 3 pounds per 100 square feet has given good control. 
Wait 2 to 4 weeks after benching before applying. It is better to apply P40 in 2 applications, 
1/2 pounds each time, 7 to 10 days apart. The latest findings show that foliar nematodes can 
be controlled with Parathion either as an aerosol or liquid spray. 
Diseases and Their Control 
COLLAR ROT or STEM ROT 
SYMPTOMS. The area of stem just at the soil level will show dark colorings first. The entire stem 
will be girdled and eventually the plant will turn yellow and die. Usually caused by the common 
damping off organisms such as Rhiztonia, Fusarium or Pythium. More prevalent when tempera- 
ture and humidity are high. 
CONTROL. Do not plant cuttings that have been affected with damping off. Remove all affected 
plants when noticed. Do not keep the soil too moist. Run a lower humidity if possible. Plant cut- 
tings no deeper than depth they were in propagating media as too deep planting will hasten de- 
velopment. Have soil well prepared as compact soils will also encourage trouble. 
MILDEW 
SYMPTOMS. Whitish powdery growth on upper surface of leaves. 
CONTROL. Spray at regular weekly intervals with a good Wettable Sulfur, | lb. per 100 gallons of 
water to which a good commercial spreader has been added. Parzate, | ounce to 4 gallons of 
water is effective. 
BIOLOGY OF THE FOLIAR NEMATODE 
Eelworms becoming Eelworms entering leaf Eelworms feeding and breeding in leaves Eelworms overwintering in 
active and commencing through the stomata. and migrating upwards from leaf to leaf. soil, dead leaves and 
their migration from (Spring-Summer) (Spring-Autumn) in basal buds. 
the ground up the out- (Winter) 
side of the stem and 
leaf-stalks into the 
basal leaves. 
(Spring) 
