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ORCHID DISEASES AND 
INSECTS 
DISEASES—Almost the only disease 
attacking orchids in the small collection 
is Black Rot. This is usually caused by 
too much water or too much humidity. 
The symptoms are soft black, dead 
areas in the leaf or bulb—often edged 
with yellow. This disease on plants 
that are kept wet at night or in a too 
humid house spreads rapidly. There is 
no cure—that is, you cannot bring the 
dead areas back to life. It can usually 
be arrested by cutting out, with a sharp 
clean knife, the affected areas. Be sure 
to cut back far enough from the dead 
or discolored area to be in clean healthy 
tissue. Then dust the cut area with 
powdered sulphur and keep the plant 
and the rest of the collection drier than 
normal for the next several weeks. 
INSECTS AND ANIMAL PESTS—Only 
three or four insect or animal pests of 
orchids are not controlled by Fenorco 
spray containing DDT. These are mice, 
mites, including red spiders, springtails 
and snails (or slugs). For mice, traps 
or baits containing Warfarin are prob- 
ably best. Mites (microscopic generally 
brown or red spider-like insects that 
turn leaves of Dendrobiums, Cyriped- 
iums, Cymbidiums, etc.) grayish, are best 
controlled by Dimite, or by washing in 
soap suds, or by dusting with sulphur. 
Springtails (the small soft-bodied some- 
times jumping insects occasionally seen 
on the osmunda or pots) are easily killed 
by dusting the pot and osmunda with 
10% Chlordane powder. 
Snails and slugs are probably the worst 
of the above. The only control we know 
for them is dusting or spraying or bait- 
ing for them with Metaldehyde. Com- 
plete control can be obtained by a couple 
of sprayings or dustings with a 50% 
Metaldehyde wettable powder. This is 
made by rubbing equal parts Metalde- 
hyde and Calcium Sulphate through a 
fine screen and then mixing it in your 
sprayer at the rate of 2 pounds to 12% 
gallons of water. Keep rapidly agitated 
while spraying—spray plants, benches, 
floors, and walls. Metaldehyde is a very 
potent stomach poison for all warm 
blooded animals, including humans, and 
must be very carefully handled. Metal- 
dehyde is obtainable from Niocet Chem- 
ical Division, U. S. Vanadium Corp., 
Niagara Falls, N. Y. 
The worst insects that affect orchids 
including ants, scale, cockroaches, sow- 
bugs, thrips, and mealy bugs are easily 
kept in check by monthly spraying or 
dipping with Fenorco Plant Spray con- 
taining DDT at the rate of 48 or 50 
parts water to one part Fenorco. 
The orchid grower with a few plants 
may disregard all of the above and keep 
his plants clean by regular washing with 
an old toothbrush with Ivory soap and 
water. 
The Anatomy of Orchid 
Plants 
Orchid plants are commonly divided 
into two groups as to their method of 
growth: Those that grow in the ground 
(terrestrials), and those that grow in 
elevated positions on trees and rock cliffs, 
etc. (epiphytes). Each of these groups 
is further divided into two types as to 
the structure of the plants. 
Orchid plants that grow with a cen- 
tral stem which grows straight up and 
lengthens indefinitely season after season 
are called monopodials. These mono- 
podial orchids have leaves that are car- 
ried alternately on the central stem and 
bloom stems come out of the central 
stem between the leaf and the stem. 
Most of these types also put out aerial 
roots where leaf and stem meet. 
Orchid plants that grow. with a creep- 
ing stem from which many bulbs or 
stems grow upright and which puts out 
new growth periodically, usually on a 
seasonal basis, are called sympodials. 
The creeping stem or rhizome (as it is 
correctly named) can branch and grow 
in several directions. This type of plant 
grows new bulbs or stems, blooms on 
them, then grows a new set and blooms 
on these. The rhizome advances period- 
ically in a lateral fashion as each new 
growth is made. 
Thus with the two main groups, 
epiphytes and terrestrials, and their two 
sub-types, monopodials and sympodials, 
we have four basic types of orchid plant 
growth. These are: Sympodial epiphy- 
tes, monopodial epiphytes, sympodial ter- 
restrials, and monopodial terrestrials. 
Examples of all four of these types are 
quite common in orchid collections but 
most of the commonly grown orchids are 
sympodial epiphytes. 
The drawings in this folder are of a 
sympodial epiphyte orchid. The rhizome 
is the stem that creeps along the sur- 
face of the osmunda (black fern root 
fiber) in the pot. Note that this rhizome 
can branch as shown in drawing No. 2. 
The bulbs, or pseudo bulbs as they are 
correctly called, grow up from this 
rhizome. The leaf (or leaves depending 
on type of orchid) grows out at the top 
of the bulb. These leaves usually will 
live and last for several years but some 
types of orchids are deciduous and drop 
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MOSQUITO CONTROL 
Several years ago we accidently found 
that our Fenorco Plant Spray contain- 
ing DDT is a very potent means of con- 
trolling mosquitoes. Sometimes here in 
South Florida we have mosquitoes float- 
ing in on the Southwest wind from the 
Everglades literally by the millions, At 
such times it is very difficult to work 
or to play outdoors. About three years 
ago we found that there were no mos- 
quitoes in our lathhouses even though 
a few feet away in the Jungle there 
were millions of them. Now we spray 
not only our orchid plants but the paths 
in our Jungle, around the office, pack- 
ing and potting sheds, etc., and we can 
completely control mosquitoes at all 
times. 
Our Fenorco Plant Spray not only 
kills the insects but it acts as a re- 
pellent and though the insects are only 
a few feet away they do not come where 
it has been sprayed. 
It is not effective at night if you have 
lights. Apparently the insects are at- 
tracted more by light than by blood. 
The spray is best applied with a power 
sprayer, and grass, bushes, buildings, 
etc., where the insects might hide should 
be covered thoroughly with it. A spray- 
ing usually controls mosquitoes for about 
10 days. 
POTTING 
There are three rules of potting: 
1. The plant must be securely held in 
the pot.—It must not wiggle or move 
when the pot is moved, the leaves touched 
or the plant watered. If the plant 
moves, the very tender little root tips 
are injured and quit growing. Firmness 
in potting is accomplished by prying the 
osmunda into the pot until no more can 
be added. Most professional potters 
pound the last few pieces into place, 
using a great deal of strength. 
2. The plant must drain easily and 
quickly—When water is poured on the 
top of the osmunda in the pot, it should 
run through immediately. 
3. Don’t overpot. Try to allow room 
for about two to three years’ growth 
only. There is no use giving more than 
this amount of room. The osmunda won’t 
last over two to three years in any case, 
FENORCO PLANT SPRAY 
Containing DDT 
The Best All-round Spray For 
Most Orchid Insect Pests 
One Einteekostpald == 
One Quart, Postpaid... 
One Gallon, Postpaid 
FENNELL ORCHID COMPANY, 
HOMESTEAD, 
FLORIDA 
