Delphinium black blotch – reduces vigour of affected plants

Delphiniums are striking border plants but can be attacked by black blotch, an unsightly disease that can affect all aerial parts of the plant. 

delphinium black blotch
delphinium black blotch

What is delphinium black blotch?

Black blotch is a bacterial disease that can affect Delphinium species and monkshood. It is not fatal, but reduces the quality and vigour of affected plants. Wet summer weather favours disease development.

Symptoms of delphinium black blotch?

delphinium black blotch
delphinium black blotch

You may see the following symptoms:

  • Rounded to irregular brown-black blotches, sometimes quite shiny, develop on leaf surfaces (particularly the upper surface)
  • The blotches may enlarge or merge together to affect a large surface area, in which case the leaf may turn brown and shrivel
  • Leaf stalks, stems and flowers may also be affected
  • Heavily infected plants are stunted and lack vigour

Control delphinium black blotch?

delphinium black blotch
delphinium black blotch

Non-chemical control

  • Dispose of affected plants as soon as symptoms are seen
  • Do not save seed from affected plants
  • If replacing diseased plants with new stock, plant on a fresh site
  • Do not purchase plants with any signs of leaf blotching

Chemical control

  • There are no fungicides available for the treatment of black blotch

Biology

The bacterium Pseudomonas syringae exists as a number of different strains, known as pathovars and abbreviated to ‘pv’. Most of these strains, including P. syringae pv. delphinii, have a restricted host range.

Black blotch of Delphinium has not been studied extensively, but it is thought that the bacterium can overwinter on old plant debris in the soil. Bacteria are then splashed up by rain to affect the current season’s foliage through the air pores (stomata) on the lower leaf surface. Prolonged spells of wet weather will allow further spread of the disease over the plant.

To prevent this disease, people can use the following products:

ONE CLEAR 50WG ATT – BLACK BLOTCH IN DELPHINIUM

ONE CLEAR 50WG
ONE CLEAR 50WG

INGREDIENTS OF ONE CLEAR 50WG

Azoxystrobin 20% w/w

Cymoxanil 30% w/w

USES OF ONE CLEAR 50WG

ONE CLEAR 50WG
ONE CLEAR 50WG

One Clear 50WG is a strong systemic and systemic fungicide, effective in preventing and treating many different types of harmful fungi, has a wide spectrum of action and is widely used in many climates and many types of crops.

The active ingredient has been registered worldwide to prevent diseases such as: Stem cracking, root rot, fruit rot caused by Phytopthora, canker, downy mildew, powdery mildew, etc.

With the characteristics of rapid penetration and strong systemic action, the drug is highly effective in preventing diseases, protecting crops comprehensively.

INSTRUCTIONS FOR USING ONE CLEAR 50WG

ONE CLEAR 50WG
ONE CLEAR 50WG

Registered product: Powdery mildew/rose

Dosage: 0.5 kg/ha. Spray when the disease first appears, the disease rate is about 5-6%.

Drum spraying: Mix 100gr for 200 liters of water.

Machine spraying: Mix 15 – 20gr for 25 liters of water.

Airplane spraying: Mix 100gr/5 hectares.

Amount of water sprayed: 500 – 600 In/ha.

Distance between outbreaks: 7 days.

#ONECLEAR #blackblotch #Powdery mildew

GOOD LUCK

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