PAPHIOPEDILUMS: Their Diseases and Insect Pests

Orchid Doctor Paph Alliance

by Robert M. [Bert] Hamilton (Compiler)

Originally published in The Orchid Doctor in 1980 and 1988

Posted by Sys Admin over 7 years ago.

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For an up-to-date review with controls, refer to OD83-55
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Paphiopedilums Comments
PAPHIOPEDILUMS: Asexual Propagation Multiplication of explants in vitro produces 200 or more plants in a year from one source; refer to A88-274 0
PAPHIOPEDILUMS: Blooming Frequency Variation Paph. Maudiae blooms freely even on a windowsill; Paph. Claire de Lune blooms regularly but not freely; Paph. harrisianum is unusually free-flowering. A69-524 0
PAPHIOPEDILUMS: Bloom on Short Stems Stem length is affected by light, and strong light tends to produce short stems; heavy shade is conducive to long stems; Paph. Maudiae can produce very long stems. A75-192 0
PAPHIOPEDILUMS: Breeding Its history in Europe with the outstanding hybrids in perspective; an American viewpoint. W9-43;; -49 0
PAPHIOPEDILUMS: Browning of Leaves It starts at the base, is caused by Erwinia cyprepedii for which there is no safe cure; it is not always caused by watering, but stale air conditions can contribute to its development; try drenching with Physan or Benlate and prune away the browned parts. OR82-10I 0
PAPHIOPEDILUMS: Buds, Browning Caused possibly by insufficient reserve food; or, infection by fungus; or, low light intensity and too high temperature at night. A78-698 0
PAPHIOPEDILUMS: Clonal Propagation One application of Benzyladenine (Imgl- IBA) to a flowered division near the base will produce an axillary bud, thus valuable clones can be multiplied more rapidly under simple greenhouse conditions without risk; refer to A77-418 0
PAPHIOPEDILUMS: Colors of Flowers They must be clean, clear, concentrated and contrasted to rate highly; is redder better?; vinicolors; culture and color; light used for evaluation of color; refer to SA87-21 0
PAPHIOPEDILUMS: Cool Growing, and Warm Growing The first have solid green leaves the second have mottled or tessellated leaves; the division is misleading since some "cool" growing plants need 55 deg.F. nights; most others need 65 deg.F. nights; Paph. venustum, tessellated needs cool conditions. A79-892 0
PAPHIOPEDILUMS: Deflasking A new mix for P. rothschildianum seedlings is 35% rockwool, 35% firbark, 10% Styrofoam chips, 10% meranti (Shorea -- not in the R.H.S. Diet, of gardening) sawdust, 10% volcanic pumice; South Africa. A86-583 0
PAPHIOPEDILUMS: Fertilization Schedule Monthly feeding should be enough; if the medium is largely peat moss use 18-18-18 ratio; if bark use 30-10-10, either at the rate of one ounce to 5.5 gallons of water. A&3-1074 0
PAPHIOPEDILUMS: Fertilizing They do well without it for as long as several years then become poor in condition; feed at one-fifth strength high in nitrogen weakly, not weekly; water the day before. OD86-139 0
PAPHIOPEDILUMS: Fertilizing Over-done It causes scorched areas most likely at leaf tips. A78-606; 1/2 tpg. 30-10-10 every 3 weeks, all plants. A80-739It causes slow growth, hard leaves and a yellowish tinge. A78-606 0
PAPHIOPEDILUMS: Flowering of Green-leafed Plants, Induced For two to eight weeks in the fall provide night temparature of 55 60 deg.F., with 77 deg.F. days. A79-894 0
PAPHIOPEDILUMS: Flowering Produced by Shock Treatment Reluctant hybrids require a change in their growth pattern such as by dropping temperature to 40 deg.F. from the normal 55, and withholding water until the compost dries; or, by dividing the plant to one mature growth size. OD72-19 0
PAPHIOPEDILUMS: Flowers, Numbers on a Stem Conditions of culture are the best influences; growers should be happy to see two flowers on a stem; if the first flower is deformed, the solution is to cut it off as soon as the deformity is seen. A71-312 0
PAPHIOPEDILUMS: From High Elevations They are accustomed to pure water and if they are subjected to sodium, regardless of other factors, turn up their toes, especially P.delenatii and P. wardii. OD83- 30 0
PAPHIOPEDILUMS: Getting Them to Grow On repotting, the roots cannot take water until a new tip grows, which can only be initiated by high moisture content around, not in, the pot, so wrap a root- less plant in foam rubber and stick it in a wide-necked bottle wrapped in foil or painted black, fill the bottle with dilute water fertilizer solution. OD81-186; Dutch expertise: OA88-8 0
PAPHIOPEDILUMS: Growing Under Lamps Success, with control of heat, light, ventilation, humidity, medium, potting, watering, fertilizing, insect and pest controls, benches, buying plants; for details refer to OD86-99 0
PAPHIOPEDILUMS: Growth, Gnarled It is caused by low atmospheric humidity. A77-798 0
PAPHIOPEDILUMS: Hard, Strap-leaved Types Patience is necessary to get these to flower, including: P.bodegonii, haynaldianum, rothschild- ianum, parishii, lowii, philippinense, etc.; most of which produce good root systems; they like 55 dF night temperature and hot days. OD82-45 0
PAPHIOPEDILUMS: Hybridizer's Nightmare Problems include sparseness of seed, incompatible crosses, sterile off-spring, dissimilarity among siblings, few good breeders (plants not people), and the diff- iculty of obtaining them for breeding. SA87-8 0
PAPHIOPEDILUMS: Hybrids with Phragmipediums Are they possible? -- although some attempts have been made, there are few flowers; for the history, cytological studies, chromosome counts, etc., refer to A85-6x 0
PAPHIOPEDILUMS: Leaf Growth Between the first of June and the end of December a required complement of leaves must be produced in order to mature the plant for flowering; fertilize at half strength three out of four waterings. A71-309+ 0
PAPHIOPEDILUMS: Leaf Loss Bottom leaves go yellow and fall off because of poor water quality, or too much light, or incorrect feeding, perhaps a lack of magnesium, or even not enough water. OA80-80 0
PAPHIOPEDILUMS: Leaf-tip Browning, or Die-back It is caused by over-feeding; transpiration in the leaves provides a surplus of chemical feed in the cells which clog the circulatory system. A71-311 0
PAPHIOPEDILUMS: Leaf-tip Die-back Is caused by too much fertilizer, or a calcium deficiency, or drying-out of the plant, especially during days of high temperatures. A83-1156 0
PAPHIOPEDILUMS: Light Control Response for December-february Flowering There is no response; they respond only to temperature control. A65-152 0
PAPHIOPEDILUMS: Light Requirements Light as for cattleyas produce better results, harder growth but shorter stems; for longer stems, shade them before flowering to about 800 -- 1,000fc. F74-68They need year round 7500 Lux; a clear summer day on the 40th north latitude is 75,000 Lux; a dark December day provides 750 Lux; 14 hours at 7500 Lux provides about 100,000 Lux-hours; hard-leaved types need 25% more than that. OD81-186 0
PAPHIOPEDILUMS: Limestone Requirements Plants which grow on limestone cliff faces, or terrestrials and epiphytes in limestone areas: Paph. bellatullum, chamberlainianum, concolor, curtisii, delenatii, exul, fairieanum, glaucophyllum, godefroyae, haynaldianum, hirsutissimum, hookerae, insigne, laurenceanum, niveum, philippinense, sanderanum, spicerianum, storei and tonsum. A75-125Roots of plants in nature grow, not on limestone, but on neutral vegetative compost; lime or limestone is very effective in culture of Paph. bellatulum, concolor, delenatii, niveum, etc. OD73-135; discussion, refer to OD70-133 0
PAPHIOPEDILUMS: Limestone Requirements for Malaysian Types Use pulverized limestone, or ordinary agricultural limestone, at one level teaspoon to a four-inch pot; best to mix it with the medium before potting, but it can be added after potting. A66-494; A67-139 0
PAPHIOPEDILUMS: Minimum Optimums For plain leaved: 50 deg.F. to 55 deg.F. at night; relative humidity 60%; 800fc. winter and 1,000 to l,500fc. summer; mottled leaved: 60 deg.F. at night; 60 to 70% relative humidity; 800fc. in winter and 1,500fc. summer. AU71-135 0
PAPHIOPEDILUMS (MOTTLED LEAVES): Problem Plants How to grow them: they need heavy shade, especially around early springtime; high temperatures can check their growth; lots of air movement is necessaary all year round and yet high humidity must be maintained also; damping down twice a day is recommended in summer; water as soon as the mix dries; use a high nitrate feed in spring and a potash feed in summer, fall and winter; the type includes Paph. argus, Paph. appletonianum, Paph. barbatum, Paph. callosum, Paph. ciliolare, Paph. purpuratum . OR&1-62 0
PAPHIOPEDILUMS: On Limes Tone Warm water in nature does not di ssolve the rock but cold water will and the plants will deteriorate in even the best conditions in cultivation. OD83-30 0
PAPHIOPEDILUMS: Palco Wool as Medium They grow poorly in shredded redwood bark, possibly because it is too acid. OD68-9 0
PAPHIOPEDILUMS: Ph of Potting Mix PH is checked every six weeks and when it is under 6.0, too low, plants are watered with dilute dolomite. A75-711 0
PAPHIOPEDILUMS: Pollination Column and anthers, location = for an illustration, refer to A57-247Select two plants for hybridization; either remove the pouch of the pod plant, or with a razor slice off the rear of the pouch; uncover the stigmatic surface; with a pointed match or toothpick remove the pollen from the pollen parent carefully from the column behind the staminode; then apply the pollen to the stigmatic surface found between two pollens; pray. OR78-317 0
PAPHIOPEDILUMS: Pollinization The stigma and how to find it: it is a foot-like structure suspended by the column; it hangs down into the pouch; the under surface receives the pollen. A78-309 0
PAPHIOPEDILUMS: Pots and Their Influence on Growth Growing them in clear plastic pots produced an improvement in growth almost unbelievable; in dark plastic pots the plants were sick; in clay many grew well. A69-573+ 0
PAPHIOPEDILUMS: Potting Mixes Eleven formulas as used by leading commercial firms, with ingredients and measurements, and additives; reprint of 1975 data; refer to OA81-82 0
PAPHIOPEDILUMS: Potting Techniques Pot firmly without crushing the roots; to examine root development strike the rim of the pot on the bench, examine the roots without disturbing the compost, then replace; new roots show at the side of the pot-ball. A76-507 0
PAPHIOPEDILUMS: Problems and Pests Repot ting, propagation, mealybug control, bacterial rot, flower-blight, genetic confusion, leaf-tip die-back, necrosis,etc.; refer to A82-1157 0
PAPHIOPEDILUMS: Problem Taxonomy A new revision or two of the genus have shown the divergent views of the splitters, Dr.Fowley, for instance as compared with the lumpers, Dr. Cribb, for example; a brief review of the problems and conflicts; refer to OA83-112 0
PAPHIOPEDILUMS: Propagation by Mericloning Has not yet been successful because shoot apices have a low survival rate in tissue culture, survivors produce a single plantlet, without proliferation. AU83-20 0
PAPHIOPEDILUMS: Recovery Treatment for Troublesome Plants They were set back because they were potted in live sphagnum moss which has a pH of about 4.5 to 5.0, which is too acid for many paph. species; but in spite of this, when they were watered with rain water or distilled water only they made remarkable recovery and continued growth A78-827 0
PAPHIOPEDILUMS: Repotting Caused previous success -- turn to failure; roots were not produced: barely possible the plants needed lime; safely add 1/2 cup of pulverized limestone per cu.ft. of mix. A68-617 0
PAPHIOPEDILUMS: Repotting Frequency Required Every two to three years; salt deposits can be controlled by adequate watering; clay and plastic pots do not differ much in salt accumulation. A70-798 0
PAPHIOPEDILUMS: Repotting Time Repot during the period of most active growth usually late spring or early fall, they will grow and flower much better. OA81-183 0
PAPHIOPEDILUMS: Roots Are Phototropic Growing in white plastic pots roots mass on the side of the pot facing the sun. OD70-136 0
PAPHIOPEDILUMS: Roots Lost on Purchased Plants As the roots were lost six to 12 months after the purchase it must have been due to excess fertilization or salts in the water supply, with periodic drying. A76-611 0
PAPHIOPEDILUMS: Rots That Attack Them They are highly susceptible to Brown rot, caused by Erwinia bacteria; cut away the lesion and treat the cleared spot with Natriphene. Ca81(2)-29 0
PAPHIOPEDILUMS: Shading Required in New Jersey About 75 or 80% shade is required in summer. A74-708 0
PAPHIOPEDILUMS: Staking of Flowers Usually done to present the flower in an upright position; in nature, the dorsal sepal prevents rain from filling the pouch so the pollinator will not drown; as the bud opens, tilt the pot forward 30% for a week after the flower opens, then stake it upright. A71-314 0
PAPHIOPEDILUMS: Stem Length It is controllable in many plants; short stems may be caused by too low night temperatures during the flowering season or too high light intensity; 60 deg.F. and reasonable shade give good stem length. A71-311+ 0
PAPHIOPEDILUMS: Stems Are Too Short They are grown under too much light. A76-206 0
PAPHIOPEDILUMS: Strap-leaved Kinds Long-petailed species and hybrids present problems of flowering successfully; for cultural advice refer to OA&5-172 0
PAPHIOPEDILUMS: Temperature Requirements in a Nutshell Cool: P. insigne, fairrieanum, and druryi ; Moderately cool: exul, gratrixianum, hi rsutis s imum, villosum, spicerianum, venusturn; Moderately warm: the multiflowered kinds such as phiiippinensis, bodegonii parishii, haynaldianum, etc.; and Warm: stonei, rothschildianumJ praestans, lowii, etc.; for full list refer to OD81-188 0
PAPHIOPEDILUMS: Temperatures to Set Bulbs The time of year to set low temperatures varies with the species; some need 55 deg.F. nights for two to three weeks beginning in March; December and January types need 55 deg.F. for two to three weeks in July to early August. A77-798 0
PAPHIOPEDILUMS: To Force Blooming In the home, place the plants on an unhealed windowsill in December or January for a month and do not water . OIE87Jan-3 0
PAPHIOPEDILUMS: To Show Flowers Off to Advantage Let the flower open for ten days before tying it upright to a stake. Ca8lMar-9 0
PAPHIOPEDILUMS: Under Lights No tight rules apply, let the temperature range be whatever seems reasonably normal but raise the lamps if it reaches the high eighties and add more air circulation; humidity is reasonably good in a closed off room summer and winter; try to use rainwater on both seedlings in plastic pots and matures in clay pots; after some trials GroLux "Wide Spectrum" tubes are preferred because they are dependable and comparatively cheap, but they should be replaced every 18 months; keep them lit 13 hours daily; fertilize with 20-20-20 at half strength monthly and always water the day before; refer to OD82-147The cool-growing types like fir bark with lots of perlite, charcoal and oak leaf mold; keep light s on 12 hours daily and keep the fans running on watering days; dry air can cause fungus problems; fertilize with 30-10-10 in summer outside and alternate with fish emulsion. OIE85Sept-ll 0
PAPHIOPEDILUMS: Vinicolor Types A proposed horticultural term "vinicolor" to be applicable to only a restricted number; definition given. A85-1428 0
PAPHIOPEDILUMS: Warm Growing Species Grown with Phalaenopsis They both enjoy good phalaenopsis cultural conditions. A83-1156 0
PAPHIOPEDILUMS: Warmth Required For all hybrids and most species the night minimum temperature should be 64.4 dF to 71.6 dF (18 to 22 dC) and 86 dF to 95 dF (30 to 35 dC) during the day maximum; low temperatures retard growth and shorten the stems. OD8I-186 0
PAPHIOPEDILUMS: Water in Pouches To drain them, pierce the bottom of the slipper with a needle; place powdered fungicide inside the slipper; use cotton covered toothpicks to mop it up. ODA69-112 0
PAPHIOPEDILUMS: Water Is Their Basic Need Rod McLellan grew 15 plants for five years in a tray of water one inch deep, and had flowers just as prolific as from plants watered several times a week. OD69-307 0
PAPHIOPEDILUMS: Water Needed Leaves may be yellowish-green, stunted, and may be flaccid because of too little water. A78-606 0
PAPHIOPEDILUMS: Weak Flower Stems P. bellatulum and concolor characteristically have weak stems. A88-34 0
PAPHIOPEDILUMS: Yellowing of Leaves Caused by a deficiency of magnesium, especially among hybrids, it can be cured by watering witti Epsom Salts (Magnesium Sulphate), at the rate of one heaping teaspoon in a cup of warm water which is then added to a gallon of water which is applied to the plantpot once a month. OR85-5 5 0

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