re 3 
Pests and Their Control 
Foliar Nematode 
The spread of this pest has been very rapid in recent 
years owing to the increased trade in chrysanthemums 
and the ease with which the nematode is transported 
in plants and cuttings. Too few growers have become 
familiar with this pest, and consequently 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 due to excessive watering, the spread 
of the pest may be extremely rapid. 
CONTROL. P40 applied at the rate of 3 pounds per 
100 sq. ft. has given good control. Wait 2 to 4 
weeks after benching before applying. It is better 
to apply P40 in 2 applications, I!/. pounds each 
time, 7 to 10 days apart. The latest fide show 
that foliar nematodes can be controlled with Para- 
thion either as an aerosol or liquid spray. Systox 
emulsion applied as soil drench 2-4 weeks after 
planting is effective, 
Diseases and Their Control 
Bacterial Stem Rot 
SYMPTOMS. Cuttings may appear healthy although 
infected, grow well up to 8-12 inches high when the 
stem becomes soft and off-colored, Pith is jelly-like 
or lacking in such stems. Tops of plants then turn 
black, exude drops of liquid, and the stem often 
splits. Develops at high temperatures (75-90 de- 
grees). Often shows up after the plants are pinched. 
CONTROL. Remove and burn immediately all af- 
fected plants. Wash hands thoroughly after handling 
plants. Steam infested soil before replanting. Avoid 
dips for cuttings. 
Collar Rot or Stem Rot 
SYMPTOMS. The area of stem just at the soil level 
will show dark colorings first. The entire stem wil 
be girdled, and eventually the plant will turn yellow 
and die. Usually caused by the common damping- 
off organisms such as Rheccane Fusarium or 
Pythium. More prevalent when temperature 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 cuttings no 
deeper than depth they were in propagating media, 
as too deep planting will hasten development. Have 
soil well prepared, as compact soils will also en- 
courage trouble. 
Mildew 
SYMPTOMS. Whitish powdery growth on upper sur- 
face of leaves. 
CONTROL. Spray at regular weekly intervals with a 
good Wettable Sulfur, 1!/. pounds per 100 gallons 
of water to which a good commercial spreader has 
been added. Spray with Iscothan 4 ounces per 100 
gallons of water plus spreader whenever disease 
appears. 
BIOLOGY OF THE FOLIAR NEMATODE 
Eelworms moving from 
the ground up the out- 
side of the stem and 
leaf-stalks into the 
basal leaves, (Spring) 
Eelworms entering leaf 
through the stomata. 
(Spring-Summer) 
Eelworms feeding and breeding in leaves x 
and migrating upwards from leaf to leaf 
Eelworms overwintering in 
soil, dead leaves and 
(Spring-Autumn) in basal buds. (Winter) 
