CHRYSANTHEMUM 
CUTTING § 

Parathion 
Parathion, as an insecticide, was discovered by chemists and entomologists of the |. G. Farben 
Corp. in Germany during the war, as a result of preparing and testing over 300 phosphorus com- 
pounds, following earlier work on phosphorus-fluorine compounds for war gases. 
This new insecticide shows promise of being the most important material yet discovered for green- 
house pest control. Parathion remains effective for a week or more both as a contact and stomach 
poison. This continued killing effect is very important in giving better control of many pests with 
fewer applications. . 
Parathion aerosol is very effective against many of the pests attacking chrysanthemums and it is 
safe on all varieties listed in this manual. If moisture is present on the foliage or bloom, a burn 
is certain. Parathion aerosol will give control of red spiders, mites, black aphids, green aphids, the straw 
colored aphids, thrips, greenhouse leaf tyers, mealy bugs and the leaf miners. 
The Parathion aerosol is applied in the same manner as the HEPT aerosol, through an applicator 
consisting of a flexible hose, brass rod and oil burner nozzle, directing the aerosol mist into the 
air above the plants. A gas mask and protective clothing should be used when applying this in- 
secticide. | 
Greatest effectiveness is obtained with temperatures of 75°F or above at the time of application 
and with vents kept closed for four hours, although excellent kills have been secured at temperatures 
as low as 65° and with vents closed for only two hours. Dr. Blauvelt, Cornell University, reports that 
parathion aerosol was applied with safety to many commerical greenhouse crops. 
Parathion Spray 
To use Parathion as a spray use the 15% wettable powder at the rate of | pound per 100 gallons of 
water. This form of Parathion is just as effective on the same pests as the Parathion aerosol. Even 
more care should be followed in using Parathion as a spray. Be careful to cover all skin, especially 
hands and always have mask on when spraying. Sprays are useful for cleaning up spot infestation 
or on crops out of doors. 
CULTURED STOCK 
Through the development of science your chrysanthemum cuttings have all been grown from stock 
that has been cultured to determine the presence or absence of the fungus that causes Verticillium 
Wilt or more commonly referred to as Seidewitz Disease. The culturing of cutting is to place bits 
of the stem of a cutting into the gelatine-like agar medium which is used for growing fungi. If the 
tissue is not infected, no growth of Verticillium develops. As each cutting is cultured it is placed in 
sterile propagating benches spaced six inches each way. After 10 days of incubating the agar plates 
one can determine if the wilt organism is present in the tissue. All the cuttings that show the pres- 
ence of Verticillium are discarded and only those that show a negative reading are saved and grown 
into stock plants. This clean stock must be grown under sterile conditions at all times as cuttings can 
be easily contaminated when planted into soil that has the Verticillium organism present. 
Verticillium wilt is one of the worst diseases of the chrysanthemum. If you obtain cuttings propagated 
from cultured stock and provided you grow your plants in clean soil this disaase should not be of 
any trouble to you. 
Popcorn—Early White Pompon 
with Proper Dress for Applying 
31 

