Diseases of anthurium Carnation and Rose.Prepared by Varu Gaitonde.

Important Diseases of Anthurium,Carnation

and Rose

Varsha GaitondeSr MScDept.of Genetics and plant breeding.GKVK UAS Bangalore

Diseases of Anthurium

Anthurium Blight

• A bacterial disease.Xanthomonas axonopodis pv. dieffenbachiae

Source-affected plant residues.

Bacterial Wilt Ralstonia solanacearum•Symptoms:

•Leaf yellowing (chlorosis) is usually the first symptom observed. •The disease spreads rapidly throughout the vascular system of the plant, turning veins in the leaves and stems a brown, bronze color .•Bacterial ooze (brown slime) will be present if cuts are made into the stems of highly infected plants. Plants will exhibit wilt symptoms even though adequate soil moisture is available.

Black Nose Disease: Colletotrichum gloeosporioides

• Symptoms: Black nose can cause havoc in cut-flower and potted-plant production. Flowers and flowering potted plants cannot be sold with this condition.

• The first symptoms observed are small, brown to black flecks on the floral spadix (nose) These spots rapidly enlarge, become watery, turn brown to black, and may totally encompass the spadix. The spadix may eventually fall off. Growers may also observe black, spore-containing structures (acervuli) on dead leaves and stems.

• Source-Splashing water,air movement and workers.

Root RotsRhizoctoniaPythiumPhytophthoraSclerotiumFusarium

PythiumPythium,Phytopthora and Rhizoctonia Pythium spp

Root Rots - brown, mushy roots due to too much water. Wilt, yellowing. Abscission of leaves from the base

up. Death of the roots results.

Diseases of Carnation

• Fusarium wilt(Fusarium oxysporum f.sp. dianthi)• In young plants, the first sign of the disease is fading

or graying ,wilting of the leaves and young stems. • It is followed by eventual collapse of the whole

plant. • When older plants are infected, similar symptoms

are produced but the older leaves may show chlorosis followed by an indistinct purple-red discoloration.

• The vascular tissues of infected stems is stained dark brown.

• Mature plants show wilt symptoms over a period of several months before they die and eventually become straw coloured.

Alternaria leaf spot (Alternaria dianthi)

• Symptoms• The blight or rot at leaf

bases and around nodes, which are girdled. Spots on leaves are ashy white.

• The centre of old spots are covered with dark brown to black fungal growth.

• . Branches die-back at the girdled area and black crusts of conidia are formed on the cankers

. Bacterial wilt (Burkholderia caryophylli)

• The upper parts of established plants turn pale and wilt.

• The stem develops elongated discolored stripes and split.

• The roots are rotted partially and the cortical tissues become sticky and shows discoloration.

• The leaves are twisted. The roots remain discolored.

• Source-Infected samples,and weed hosts.

• Carnation vein mottle virus (CVMV)of "colour breaks" and calyx splitting are greater. CVMV is spread from plant to plant by aphids and is found wherever carnations are grown

• Carnation etched ring virus (CERV)• Carnation mottle virus (CarMV)• Carnation latent virus (CLV)

Carnation necrotic fleck virus (CNFV)

Alternaria blight

Alternaria saponariae

= Alternaria dianthi

Alternaria dianthicola

Anther smut Ustilago violacea

Calyx rot Stemphylium botryosum

Pleospora tarda [teleomorph]

Charcoal rot Macrophomina phaseolina

Downy mildew Peronospora dianthicola

Fairy-ring leaf spot Mycosphaerella dianthi

Cladosporium echinulatum [anamorph]

Fusarium bud rot Fusarium tricinctum

Fusarium stem rot Fusarium graminearum

Gibberella zeae [teleomorph]

Diseases of rose

• Powdery Mildew

Sphaerotheca pannosa

Fungal thread on leaf surface

Air borne.

Common in crowded plantings where air circulation is poorThe fungus can over winter on infected canes, and leaves left on the bush.spores move to new growth foliage in spring to begin disease cycle.

Black Spot

• One of the most common diseases of roses • Disease cycle typically begins on leaves or canes

infected the previous season • Leaves less than two weeks old are the most

susceptible• Lower areas are more likely to be infected as spores are

splashed up on new foliage during rains or irrigation– will continue up the stem - as disease spreads, leaves go from green to yellow and then drop

Diplocarpon rosae

Downy Mildew• A very serious disease that can affect all

roses!

• May appear only when favorable conditions

of humidity over 85% and temps of 65 - 75°

F

• Under cool and moist spring conditions,

young leaves, stems and flowers may show

purple to red or brown irregular blotches

that tend to follow the leaf veins

• Advanced infections will have yellowing of

leaves

Peronospora sparsa

• Initially spots are small and black - easily confused with blackspot

• Spores believed to be carried by water or rain to new leaves and stems

• As disease progresses, spots become purple to brown and centers turn gray or white with dark margin

• This light-colored center best defines the difference with blackspot

• Can be severe under cool, moist spring conditions

Sphaceloma rosarumAnthracnose

Botrytis Blight

• When the weather is cool and wet, the conditions are right for this fungus

• Most common symptom - young flower buds droop, turn black at the base

• Later produce the cottony grey-black mycelium of the fungus

Botrytis cinerea

Gail Trimble

Rose Canker

• A fungal disease that can affect any part of the plant, but most common on stems and canes

• After a cold wet winter, pruned stems provide wound sites for canker causing fungi

• Canker can also enter thru leaf scars – do NOT tear off leaves during fall pruning!

• The stems will yellow, often have red spots and later become brown or black

Coniothyrium spp

Rust

• A fungal disease common in many areas, easily identified

• Appears on the underside of the foliage as red-orange spots

• Thrives in cool, moist weather• The summer stage is cyclic, and

may repeat every 10 to 14 days in favorable weather

• Fungus overwinters on infected leaves and canes

• Spores are wind borne

• Can defoliate the plant

Phragmidium spp

Bacterial Crown Gall

• Bacterial disease usually seen on bud union, or on the trunk

• Thrives in warm, sunny weather; not active in cold weather

• Cork-like substance that will turn brown and harden as it ages

• Plants will usually be stunted in their growth habits

Agrobacterium tumefaciens

Rose Mosaic

• Probably the most commonly found virus in roses

• Mosaic is primarily transmitted by propagation

• Usually appears in spring as a distortion of growing tips and leaves

• Symptoms include coloration patterns (shown), distorted leaf growth, slow to develop, and fewer quality blooms.

• Transmitted by infected stock,cuttings.

Prunus Necrotic Ringspot Virus

Rose Rosette Disease (RRD)• Exact cause unknown

• The distinctive red stems, misshapen leaves are symptoms

• The main host is R. multiflora

• New growth appears unusually soft and pliable

• RRD is suspected to be carried from plant to plant by mites

• Can be confused with plant damage from chemicals like Roundup®

Basic IDM stretegies pH of the growing media - pH strongly influences the

availability of micronutrients such as iron and manganese and can influence the development of the root system in the growing media. 

Nutrient levels and their balance - These affect the plant tissue content and can trigger toxicity or deficiency symptoms. This tissue is typically more susceptible to attack by pathogens. 

EC (electrical conductivity created by soluble salts) - High EC can damage root hairs creating a wound site for attack by root disease pathogens.

Moisture-holding capacity - Media must hold sufficient available water to prevent desiccation of the roots once the root system becomes pot-bound.

Media texture to allow good drainage - Adequate coarse-fibred peat is required to ensure sufficient aeration when the growing media is at full water holding capacity to prevent water logging and oxygen deprivation of the roots.

• Oxygen content - Adequate media aeration is critical to healthy root growth and nutrient uptake and preventing temporary exposure of roots to anaerobic conditions.

• Media temperature - Roots develop best at temperatures somewhat lower than those required for shoot growth. High media temperature causes significant root death in most crops when media temperatures are above 26-28°C.

Aerial environment characteristics that must be considered include:

• Light levels - Exposure of high light requiring plants to low light levels or heavy shading often triggers soft, weak growth that is more susceptible to leaf rot pathogens.

• Temperature Fluctuation resulys in higher incidence of root and foliar disease problems. For example, crops typically considered cool crops when grown during high temperature periods of the year are usually more susceptible to crown and root rot pathogens.

• Air movement - powdery mildew and botrytis. Open doors causing drafts and fluctuating leaf and air temperature or horizontal air fans (HAF) foliar diseases.

• Relative humidity (RH) - Fluctuating RH with high RH at night (above 90%) increases the incidence of foliar diseases.

• Air quality - Chronic low level air pollution often associated with ethylene-like hydrocarbons can trigger premature senescence of older leaves whose tissue is more prone to opportunistic fungi like Botryis.

Cultural Practices

• Symptom recognition• Sanitation and Roguing• Use footbaths between greenhouse compartments,

• Rogue the plants,and dispose properly. Dedicate wheelbarrows or soil carts used to discard diseased material strictly for disposal purposes.

• pathogen exclusion, construction of traps, pruning, and burning of diseased plants or leaves in a safe location

• Carefully check both the foliage and roots for disease.

Maintain proper drainage to eliminate puddles and wet surfaces, as these provide ideal breeding sites for fungus gnats and shoreflies. diseases such as Pythium and Fusarium.

Keep the greenhouse free of weeds that may harbour diseases. For rose, steam soil before planting winter crops to minimize the carryover of root and crown rot pathogens

Avoid extremes, as much as possible, for the crops. For example, the combination of high temperature and over-fertilization promotes Fusarium crown and root rot in cyclamen, while the combination of high temperature and high RH is favourable to Rhizoctonia attacking cuttings during or just after propagation. Also avoid low temperatures to prevent outbreaks of Pythium in warm-temperature crops.

Monitoring•reviewing crops for plant growth regulator (PGR) application or for irrigation.•monitoring or applying a fungicide:datecompartment or section in the greenhousecrop species and cultivarstage of plant development diseases present or suspectedcontrol action (pesticide used, rate, area treated, time taken, etc.)greenhouse environmental conditions (temperature, RH, light levels, shading used).

• Biosecurity• Biosecurity is a process to protect a geographic area or individual facility

from pests and diseases. It includes reducing the risk of the introduction of new pests and diseases and eradicating or effectively managing the spread of those that have already arrived.

• Disinfectants• Agribrom - used to control microbial slimes in greenhouse evaporative

cooling systems and to control algae and microbial slimes in irrigation systems.

• A 0.5-1% final solution of sodium hypochlorite bleach -Used when there is a severe disease out break.Used as a disinfectant.

• Horti-Klor - a chlorinated cleaner or detergent that can be used initially to remove algae and plant residue from packing equipment, planting lines, plug trays and coolers. Follow manufacturer's directions.

• Other compounds like Quaternary ammonium chloride, ZeroTol,Virkon ,Floralife D.C.D,KleenGrow,Strip-It etc.

Biological control

• Rootshield is registered as a bio-fungicide for suppressionof Fusarium, Pythium and Rhizoctonia on all ornamental crops.

• Actinovate SP is registered as a contact biological fungicide for PM and Botrytis.

• Regalia Maxx supress PMs. Cyclone, suppress powdery mildew and blackspot on

greenhouse roses when applied as a foliar spray. 

Chemical control• Apply chlorothalonil, propiconazole, fludioxonil,

copper hydroxide, iprodione, mancozeb, or mancozeb + thiophanate methyl to control leaf spots.

• Apply chlorothalonil, cupric hydroxide, iprodione, mancozeb, or fludioxonil for Blight.

• Plant in pasteurized, raised beds. Apply thiophanate methyl, PCNB or iprodione as a soil drench for soil borne diseases.Polyethylene film for 30 days for wilt.(1mm)

• Apply chlorothalonil, propiconazole, myclobutanil, ziram, mancozeb + thiophanate methyl, triadimefon, or triforine for rust.

Resistant varieries

• Rose-PM- • Charisma ,Pascali Rose ,Parade Chicago Peace, Prominent

Sarabande ,Europeana Pink Peace, Saratoga ,Margarita etc.

• Black spot-Angel Face, Ivory Fashion, Proud Land, Carrousel, Miss All-American Beauty, Queen Elizabeth .

Thank You

Questions?