LEAF DIE-BACK: Glomerella cincta

Ailments Orchid Doctor

by Robert M. [Bert] Hamilton (Compiler)

Originally published in The Orchid Doctor in 1980 and 1988

Posted by Sys Admin almost 8 years ago.

Article Blog   Article Index

Fungus starts at the leaf tip and spreads fully towards the base; areas turn brown, later dry out; cut it out; treat with Tersan. N318

Share on Social Media:  
Log in to Add a Comment

More The Orchid Doctor Articles under the Heading Leaf Ailments

Leaf Ailments Comments
LEAF CRINKLING: On Dendrobiums Caused by inadequate watering. A79-784 0
LEAF DIE-BACK: Fungus Disease Spreads slowly from the tip through the leaf unless cut off; Glomerella cincta infects the tip and spreads backwards with a marked line between good and diseased tissue; control with Benlate. A73-811; it is caused by a water mold Pythium splendens; cut it off and use a fungicide. S204 0
LEAF FALL: As An Indicator It is no cause for concern as most plants shed leaves sooner or later in the natural course of events. A84-584It is usually natural; leaves fall from bulbs three or four years old; may be a cultural fault such as under- or over-watering; check the roots -- if they are brown, soggy, decayed it means over-watering; if white and dry, under-watering; no great problem. 0D66-316 0
LEAF NECROSIS: Cymbidium Mosaic Virus The initial infection is conspicuous; kills some leaves, afterwards milder symptoms show; plant becomes a reservoir of infection; brown sunken pits on underside of leaves; black and chlorotic alternate streaks,or rings of dead tissue appear on the underside; some length-wise stripes of white or gray; roughness. N323 0
LEAF NECROSIS: Severe It is caused by Cymbidium necrotic ringspot virus; deadly but rare; new and old growths are killed; destroy plant. N323 see also Necrotic spots 0
LEAF ROLLERS: Characteristics and Controls The larvae of Tortricid moths can be destructive; they tie leaves together and feed on terminal growths and bore into the buds and shoots; caterpillars are yellowish or greenish, 1/2 inch long, they wriggle violently when disturbed; spray with Zectran or Sevin. RMH 0
LEAF ROT: Erwinia and Sp. of Pseudomonas Stimulated by warm, damp weather; areas are yellowish or brownish and watery; the bacteria spread quickly; cut off whole leaf; soak the plant in Anti-Damp or Natriphene. A73-815 0
LEAF SPOTS: Anthracnose Is a Common Cause Small spots occasionally run together; tissue between becomes tan and papery; fruiting bodies show as black dots sometimes as rings; sometimes caused by Circospora sp. (see Leaf-spot) with brown sunken spots or streaks; for all kinds cut off affected leaves; spray with Captan, Physan 20 or Benlate. A73-811 0
LEAF TIP BLACKENING: On Main Leaflet of Cattleyas Caused by Phytophora or Pythium diseases; best controlled by Truban (ethazole) at 1 tpg.; avoid syringing with water at adverse times. A79-1112 0
LEAF TIP BURN: Cercospora odontoglossi A fungus attacks cattleya seedlings and others; tiny raised spots dark brown in color under the leaves spread to the whole leaf; resembles spider mite injury; best control with benomyl 50% at 1 ttpg. three times fortnightly plus a wetting agent; or Ferbam, Daconil 2887, Zineb, Captan, twice a month. B22; BU25 0
LEAF TIP BURN: Cercospora peristeriae Yellowish to pale brown, oval to elongate spots appear on the under surfaces; move to the top; spray with benomyl 50WP, at 1 tpg. fortnightly to check infection. B20; BU20 0
LEAF TIP BURN: Cercospora Sp. Several fungi attack specifically cattleyas, vandaceous types, oncidiums, cymbidiums, odontoglossums; spray preferably with benomyl 50WP at 1 ttpg. fortnightly, or use ferbam or zineb; use a wetting agent. BU26+They first appear as yellowish spots; then sunken and dark; or, small brown spots which darken and become depressed or, as brown streaks; in all cases they enlarge and kill tissue; dip or soak in fungicide, such as Captan,Ferbam, Zineb, Benlate. N318 0
LEAF TIP BURN: Diplodia laeliocattleyae Sometimes found on cattleyas in Florida; small, yellow areas on top or bottom of leaf turn brown and become black, greasy areas; fruiting structures develop on older leaves; destroy all leaves; treat as for wound-infecting parasites and spray with fungicide. B27; BU35 0
LEAF TIP BURN: Fungus Invasion of Leaf Cut out the diseased parts before treating with AntiDamp or Tersan; frequently seen on cymbidiums with pendant leaf-tips which hold drops of water which attract Botrytis; use Benlate. A73-811 0
LEAF TIP BURN: Phyllostictina pyrjformis Leaf-spotting fungus infrequent in Florida and not destructive but makes plants unsightly; tiny, slightly yellow spot, sunken, becomes larger, tan to dark brown; red to purple-black margin; round singly, irregular when coalesced,on pseudobulb oval; about 1/4 inch; spray with common fungicide such as benomyl. B25+ 0
LEAF TIP BURN: Septoria selenophomoides Fungus found on many imported genera; tiny sunken yellow lesions on top or bottom surface; enlarge and become dark brown or black; spots sometimes coalesce; on older plants and fallen leaves fruiting bodies become a source of infection to other plants; destroy all fallen leaves; spray with benomyl three times fortnightly, or Daconil 2787, or ferbam; spray especially a month before regular leaf fall on dendrobiums. B24+; BU-30+ 0
LEAF TIP DIE-BACK: Cause It is caused by high soluble salt content in the water, or by fertilizer salts not flushed out. A70-55; A78-13 0
LEAF TIP DIE-BACK: Disorder of Cattleya Types Newly matured leaves show darkening of veins very close to the tip, later developing into dark, sunken spots which spread to cover three-quarters of the leaf tip ; most active in summer; many theories advanced; the conclusion: calcium deficiency. A73-227+ 0
LEAF-TIP NECROSIS: Causes It is a nutritional and compost problem and is not caused by fungal attacks as is commonly supposed; an unhealthy root system is likely at the base of it. AU84-199; it can be caused by a mix which stays too wet, or, a deficiency of magnesium and/or iron; or, possibly a buildup of sodium or sulfur. AU84-204 0

New Topics

  1. James W McCully asked question How to read archived articles ? in category General Discussion
  2. David George asked question recently purchased orchid - what to expect in category General Discussion
  3. Danielle Carbonneau asked question phalaenopsis, dendrochum and Odontoglossum in category Phalaenopsis
  4. Nicholas Filannino asked question Phalaenopsis William Kistler? in category General Discussion
  5. Mark Farran asked question How to open and read articles listed in category General Discussion
Ask a Question

Start a Topic

New Comments

  1. Louis Wilson commented on member plant E. alata f. alba by Louis Wilson
  2. Julie Ellner commented on member plant Phal. amabilis var. formosanum by Vickie Seibert
  3. Julie Ellner commented on member plant Rlc. Green Dragoon 'Mendenhall' by Jeanne Uzar Hudson
  4. Danielle Carbonneau commented on member plant Ons. Catatante 'Los Roble' by Henry Shaw
  5. Barry J Silver commented on orchid Lyon. SunCoast Pink Passion
  6. Carol Holdren commented on topic "Phalaenopsis William Kistler?" by Nicholas Filannino
  7. Carol Holdren commented on orchid Colm. Eric Gabriel Heines
  8. Carol Holdren commented on topic "Cattleya little susie" by Juliann Eckhard
  9. Carol Holdren commented on member plant Bc. Morning Glory by Chris Siolo
  10. R .Benson commented on member plant Kir. New Hybrid (Fred Clarke) SVO9831 by R .Benson
  11. Carol Holdren commented on topic "Blooming Stenglottis Venus “jamboree “" by John Urey
  12. Jeanne Uzar Hudson commented on member plant Lc. Canhamiana var. coerulea 'Cobalt' by Jeanne Uzar Hudson
  13. Jeanne Uzar Hudson commented on member plant Sns. gemmata by Jeanne Uzar Hudson
  14. Stefan Neher commented on topic "Orchid roots .com site?" by Mary Lane
  15. Kevin Barry commented on member plant Bul. Tammie Sue Pernas by Tony Pernas
  16. Linda Hartman commented on member plant Ctt. Final Blue by Linda Hartman
  17. Kevin Bergeson commented on member plant Paph. rothschildianum by Kevin Bergeson
  18. Carol Holdren commented on topic "recently purchased orchid shows unstoppable roots " by David George
  19. Michael Makio commented on orchid V. Beatrice Makio
  20. Carol Holdren commented on topic "shorter stem with less vigorous blooms" by katherine mott