White powdery stuff on my plants on the stalks and now leaves blemished

[The Hammer2021]

1) White powdery stuff on my outside potted plants, on the stalks and now leaves blemished brownish yellow blotches. What is the best fungicide or pesticide to use?

2) By what name  can I get Liquid  plant food equivalent  to phostegeon in the Europe.  A white powder that can be dissolved in water and applied in liqid form.

 

[Sheryl]

Moved to the general farming forum.

 

 

[The Hammer2021]

Thanks

[drtreelove]

From the description, it sounds like "powdery mildew".  But photos, plant ID, description of growing conditions and management would help with remote diagnosis and treatment recommendations. 

 

An advanced disease condition is difficult to cure, but suppression and preventive management may help to minimize the damage and prevent future infections.   Its best to focus on improvement of growing condtions, soil and water management that builds natural resistance to disease.

 

I would avoid high NPK chemical fertilizer products like Phostrogen liquid plant food and go with a slow release complete organic fertilzer like Organic Totto, and/or worm castings (vermicompost). 

 

Instead of chemical fungicide, I would use Potassium bicarbonate, or a biological fungicide like Trichoderma harzianum or Bacillus subtilis. 

 

POTASSIUM BICARBONATE(FOOD GRADE) for pH buffer and use as Organic fungicide | Lazada PH

 

Powdery Mildew: Symptoms, Treatment and Control | Planet Natural

 

 

 

 

 

 

 

[BritManToo]

3 hours ago, drtreelove said:

From the description, it sounds like "powdery mildew".

 Common on cannabis plants in high humidity.

[drtreelove]

18 hours ago, BritManToo said:

 Common on cannabis plants in high humidity.

Yes, but not necessarily so with best management practices.  Susceptibility is there partially due to genetics; strains are developed for certain desirable traits and disease resistance is not always a priority. 

Resistance to pests and diseases can be enhanced with good soil fertility and water management. 

 

[The Hammer2021]

Thank you for your detailed answers and sorry for the lack of detail and supportive evidence.

It's a single decorative  plant grown outside in shade in a pot. I think that may  be a problem - the shade.

I guess what I want  is a general 'broad spectrum ' all round fungicude/ pesticide systemic or otherwise- I won't be eating or smoking the plant.

I wonder if the source of stock is an issue- from the same nursery I got  plants which  wilted as though over or under watered but this  was not  the  case - I think an infestation of ants had attacked  the roots.

Is that likely  or  possible?

So you might agree I need an all round combination fungicide insecticide combined OR

Should I just throw the plant out and buy a new one?

[VocalNeal]

My wife sprays with washing up liquid mixed in water.

[drtreelove]

On 5/10/2022 at 10:49 AM, The Hammer2021 said:

Thank you for your detailed answers and sorry for the lack of detail and supportive evidence.

It's a single decorative  plant grown outside in shade in a pot. I think that may  be a problem - the shade.

I guess what I want  is a general 'broad spectrum ' all round fungicude/ pesticide systemic or otherwise- I won't be eating or smoking the plant.

I wonder if the source of stock is an issue- from the same nursery I got  plants which  wilted as though over or under watered but this  was not  the  case - I think an infestation of ants had attacked  the roots.

Is that likely  or  possible?

So you might agree I need an all round combination fungicide insecticide combined OR

Should I just throw the plant out and buy a new one?

Yes the shade is a likely factor.  Some plants are more tolerant of shady conditions than others.  So if your plant is sun-loving, and its health and resistance to disease depends on full sunlight and photosynthesis, you may be better off replacing it with a shade tolerant species, or installing artificial lighting. 

 

A broad spectrum fungicide may provide temporary control of a fungal infection, but will not correct the contributing factors that make the plant susceptible to the disease, so the disease will return, or another disease or pest will attack a weakened plant.  

 

There are organisms that can cause root damage, but ants are not likely. Ants may be present, due to favorable habitat for their nesting and nearby food sources, but they will not normally be feeding on the plant tissues. Termites could be an exception, but they feed primarily on wood that is dead already. 

 

Root-rot from soil-borne pathogens (fungi and water-molds) can originate from the original growers practices and potting soil, or from your own management, over-watering or high Nitrogen fertilization. 

 

You could re-pot the plant, with a slightly larger pot and better potting soil. And buy a soil moisture meter to take the guess work out of when and how much to water. But of course this won't correct the shady environment factor. 

[drtreelove]

On 5/10/2022 at 11:06 AM, VocalNeal said:

My wife sprays with washing up liquid mixed in water.

This is a good suggestion.  Insecticidal soap can be a useful, organic-program-compatible pesticide, but is not appropriate for all pest and disease conditions.  And it will not correct the underlying factors that weaken the plant and make it susceptible to the pest or disease. Don't use just any soap or detergent to make the insecticical soap solution, as some ingredients are phyto-toxic.  

 

The vinegar version may be useful for the powdery mildew if that's what it is. Vinegar should be used according to directions only, because concentrated solutions are toxic to plant foliage. 

 

Homemade Insecticidal Soap Recipe

The simplest insecticidal soap is nothing more than a 2% soap solution. To make this at home, you will need:

• Sprayer: Any clean spray bottle or garden sprayer will work fine for spraying insecticidal soap. Make sure the sprayer or bottle hasn’t been used for herbicides.
• Pure Soap: Use a pure liquid soap, such as Castile, or all-natural soap. The active ingredient in insecticidal soap comes from the fatty acids in animal fat or vegetable oil, so it’s important to use the real thing. Don’t use detergents (which aren’t actually soaps), dish soaps, or any products with degreasers, skin moisturizers, or synthetic chemicals. Dr. Bronner’s Pure Castile Soap is usually pretty easy to find in stores, or check your local natural-foods store for other options.
• Pure Water: Tap water is fine for making insecticidal soap. If you have hard water, you may want to use bottled water to prevent soap scum from building up on your plants.

To make homemade 2% insecticidal soap, mix together:

• 5 tablespoons soap to 1 gallon of water     OR
• 1 heavy tablespoon soap to 1 quart of water

Homemade Insecticidal Soap Recipe Variations

Like any other home remedy, there are as many variations on this recipe as there are gardeners! You can also try:

• Diluted Solution: If the spray causes damage or burns your plant foliage, cut the amount of soap in half and try a 1% solution. This is the concentration usually found in commercial sprays. The lighter solution might be less effective but is gentler on plants.
• Cooking Oil: To help the solution stick a little longer, add two tablespoons of light cooking oil (such as corn, canola, olive, or safflower) per gallon of water to the mix.
• Vinegar: To make a spray that also targets powdery mildew, add a teaspoon of cider vinegar per gallon of water to the mix.
• Garlic or Pepper: To help repel chewing insects, add a teaspoon of ground red pepper and/or garlic per gallon of water to the mix.
• Bar Soap: For a less-exact recipe, drop a bar of pure soap (such as organic bar soap or Ivory) into a gallon of water and leave it overnight. Remove the bar and shake well before spraying.

[actonion]

I had the same problem....  i read on Google  to mix a bit of vinegar  with dish washing liquid soap in a spray bottle  give it a good spray  and leave it a couple of days   removing the damaged leaves, since i did that several months ago  the  bush in question  has never suffered since

[The Hammer2021]

4 hours ago, drtreelove said:

Yes the shade is a likely factor.  Some plants are more tolerant of shady conditions than others.  So if your plant is sun-loving, and its health and resistance to disease depends on full sunlight and photosynthesis, you may be better off replacing it with a shade tolerant species, or installing artificial lighting. 

 

A broad spectrum fungicide may provide temporary control of a fungal infection, but will not correct the contributing factors that make the plant susceptible to the disease, so the disease will return, or another disease or pest will attack a weakened plant.  

 

There are organisms that can cause root damage, but ants are not likely. Ants may be present, due to favorable habitat for their nesting and nearby food sources, but they will not normally be feeding on the plant tissues. Termites could be an exception, but they feed primarily on wood that is dead already. 

 

Root-rot from soil-borne pathogens (fungi and water-molds) can originate from the original growers practices and potting soil, or from your own management, over-watering or high Nitrogen fertilization. 

 

You could re-pot the plant, with a slightly larger pot and better potting soil. And buy a soil moisture meter to take the guess work out of when and how much to water. But of course this won't correct the shady environment factor. 

'Root-rot from soil-borne pathogens (fungi and water-molds) can originate from the original growers practices and potting soil, '

I think this  might be the  cause. Thanks for your  input

[The Hammer2021]

4 hours ago, actonion said:

I had the same problem....  i read on Google  to mix a bit of vinegar  with dish washing liquid soap in a spray bottle  give it a good spray  and leave it a couple of days   removing the damaged leaves, since i did that several months ago  the  bush in question  has never suffered since

Tx