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I bought this Schefflera three weeks ago. I changed its pot from the plastic tub it came in to a ceramic one. Last week, one branch died completely; all the leaves withered. I thought I might be overwatering, so I cut back. Now the other two branches have begun to have leaf issues similar to the dead one (the white spots are dust from the store where I bought it).

Should I continue to not water this guy, or should I look for some other cause?

Leaf example

  • Does the ceramic pot have drainage holes? – Bamboo Aug 31 '13 at 10:29
  • Yes, one in the middle about 1.5cm in diameter – Josh Guffin Aug 31 '13 at 12:35
  • 1
    If you only bought this plant in the last month, I'd take it back from whence it came and ask for my money back or a replacement. If you've had it in a pot with a hole and its not been sitting in water in a tray or something, then likely this is a problem the plant had in the first place. – Bamboo Aug 31 '13 at 13:03
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The white spots are not powdery mildew. They are a mixture of pesticide residue and hard water stains from overhead watering in the grower's greenhouse. Powdery mildew is usually "fuzzy" and residue is flat on the leaf.

Either way wiping the leaves with a cloth is sufficient as a first stage. If it is powdery mildew it will return, residue will not.

The necrotic (dead) spots on the leaves are typical of root rot but can also happen if the plant has other types of fungus/virus/bacterial infection.

Given that you have repotted it the best solution is:

  • wipe off the residue and see if it returns
  • place the plant in high light
  • remove all dead leaves and stems from the soil at the base of plant
  • when the top inch of the soil has dried, apply water until it comes out the base of the pot
  • do not let it sit in water

If the plant continues to deteriorate you should return it to the store as it may have been sold to you with a fungus/virus/bacteria. A healthy plant under good conditions can outgrow minor issues.

3

Just a note on the "dust". Dust will easily wash away with water. The appearance and damage to the leaves and stems makes me think it might be powdery mildew, a fungal disease that appears as a white powdery coating on the leaves.

My experience and reading on powdery mildew is that much of it can be just washed off the plant if caught early. Once the spores attach themselves to the leaves you need something else that will help. I've found that neem oil is effective against powdery mildew and posted some more information on my site.

Another option is a diluted milk spray (1 part milk 9 parts water). I've used this as well and it does a pretty good job against powdery mildew but seems to be best to use on a regular basis before the you see signs of the disease. It's been something I've used and looked into over the years and have published some more info regarding what makes milk a good fungicide on my blog.

Lots of people have seen positive effects of using diluted milk as a foliar spray to control disease. See Tomatoes Like Milk. In recent years there have been a number of studies regarding milk and plant pathogens to figure out how milk helps. It was first thought to be that the calcium strengthened the immune system in plants but now it looks like it's the probiotics in milk that are the key. Various bacteria that have been identified in milk are effective against a wide range of plant pathogens including powdery mildew.

  • Thanks for the suggestion; the dust does come off easily, it's just that there are (were) too many leaves to wipe them individually. I have never seen the white clusters from your first link, only the diffuse covering as in the OP. – Josh Guffin Aug 31 '13 at 12:45
  • @JoshGuffin Powdery mildew doesn't always form clusters. Try it. If I'm wrong you wind up with a cleaner plant. If I'm right you have a cleaner, healthier plant and a little less milk. :) – OrganicLawnDIY Aug 31 '13 at 13:05
  • Research suggests it's the milk proteins that eradicate the fungus. Strong light transforms the proteins into superoxides, and peroxides. The leaf waxy coating protects the plant from the milk. Since milk powder also works, that rules out probiotic organisms as the mechanism. – Graham Chiu Mar 16 '16 at 18:41
  • If there are too many leaves for individual treatment, a spray with a hose, or a few minutes in the shower will usually work to eliminate dust and powders. – Wayfaring Stranger Mar 17 '16 at 14:06

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