Lily Pads getting brownish/black spots that progress

[MoonShadows]

I bought a lily about 4 weeks ago. After a few days I noticed some of the older pads were getting brownish/black spots which progressed until the whole pad was brownish/black. I figured it was just the older pads, but it is continuing and even some of the newer pads are getting these spots.

I don't think it is lack of food since the nursery put in 3 fertilizer tabs when I bought it. And, it's not water spots burning the pads, either. My comets do not seems interested in the pads at all until they are almost completely brown/black, and then they start munching on them. I've been snipping them off just above the soil level when they get bad, but at this rate the bad ones are showing up faster than the plant produces new ones.

Any ideas?

Here's a pic of how the lily looked a couple of days after I put it in the pond.

Here's what's happening now.

 

[heyatx]

It looks like something is eating the leaves. Maybe snails?? I had the same issue, got assassin snails on ebay and in 3 weeks the little black snails are almost all gone! Flip the leaves over and see what may be munching on them. Good Luck!!

 

[MoonShadows]

@heyatx Not snails...nothing on the back of the leaves.

 

[Meyer Jordan]

Some type of insect damage (caterpillars?). If so, beyond manual removal there is not much that can be done as any insecticide would be toxic to your fish.

 

[MoonShadows]

@Meyer Jordan I haven't seen any caterpillars or any other type of insect on the leaves....front or back.

 

[Meyer Jordan]

Those certainly appear to be insect cut marks on the leaves.
Have you inspected them at night with a flashlight? Many insects are nocturnal.

 

[DutchMuch]

Have you looked closely at the little black spots? It sounds like aphids. If aphids are the problem: A light coating of Pam cooking spray will suffocate the aphids. It's completely harmless to your other pond critters. Spray the waterlilies late in the day (when there's no chance for the sun to burn them) - let it sit 15 min or so and then rinse off with your garden hose.
There will be a bit of an oil slick, but your skimmer will take care of it in a few minutes. It'll dissipate soon enough even if you don't have a skimmer.

Do you have water splashing on the leaves? Water droplets will magnify the sun and burn the leaves with little round holes.

Another possibility is that the plant is suffering a form of root rot. How deep is the top of the pot below the water surface?

Last I would look at nourishment, maybe you are under or over fertilizing the plant. Lilies are very heavy feeders and do best with monthly fertilizing (with an aquatic plant fertilizer tablet). It could also be a combination of factors such as parasites, rot and water quality. Water lilies do not like high pH, (over 9.0 makes some varieties go dormant).

 

[Meyer Jordan]

What size container is it planted in. Three fertilizer spikes seems like maybe too much. Bottom line this plant has become weak, hence the yellowing and insect damage.

 

[MoonShadows]

Those certainly appear to be insect cut marks on the leaves.
Have you inspected them at night with a flashlight? Many insects are nocturnal.

No, I haven't, but I will. Thanks @Meyer Jordan. Additionally, those "cut marks" into the sides of the leaves are where my comets start nibbling at the leaves once they get like that...but it may be insects, too. The comets don't seem to be interested in the healthy leaves. Could the comets be eating the insects?

 

[MoonShadows]

Have you looked closely at the little black spots? It sounds like aphids. If aphids are the problem: A light coating of Pam cooking spray will suffocate the aphids. It's completely harmless to your other pond critters. Spray the waterlilies late in the day (when there's no chance for the sun to burn them) - let it sit 15 min or so and then rinse off with your garden hose.
There will be a bit of an oil slick, but your skimmer will take care of it in a few minutes. It'll dissipate soon enough even if you don't have a skimmer.

Do you have water splashing on the leaves? Water droplets will magnify the sun and burn the leaves with little round holes.

Another possibility is that the plant is suffering a form of root rot. How deep is the top of the pot below the water surface?

Last I would look at nourishment, maybe you are under or over fertilizing the plant. Lilies are very heavy feeders and do best with monthly fertilizing (with an aquatic plant fertilizer tablet). It could also be a combination of factors such as parasites, rot and water quality. Water lilies do not like high pH, (over 9.0 makes some varieties go dormant).

No water splashing on the leaves. I don't see any aphids...unless they are smaller than the typical aphids on regular garden plants. The top of the pot is approximately 8" below the water surface. I bought the lily 4 weeks ago. The nursery woman put 3 Aquascape fertilizer tabs beneath the soil. My pond tends to have a high pH, but I haven't tested it in the past couple of weeks. I will do so tomorrow and report back.

 

[MoonShadows]

What size container is it planted in. Three fertilizer spikes seems like maybe too much. Bottom line this plant has become weak, hence the yellowing and insect damage.

The pot is about 10" wide and 5" deep. It is a dwarf lily (3' spread range).

 

[DutchMuch]

can you cut those damaged lily leaves off, then document if any others get damaged as well?

 

[Meyer Jordan]

No, I haven't, but I will. Thanks @Meyer Jordan. Additionally, those "cut marks" into the sides of the leaves are where my comets start nibbling at the leaves once they get like that...but it may be insects, too. The comets don't seem to be interested in the healthy leaves. Could the comets be eating the insects?

Looks very similar.
Cutworm damage. Nocturnal. Several species of moth.

 

[DutchMuch]

Shoot if that's cutworm damage on the lily its awfully small.
if that's what it is, get it fixed before they reproduce.

 

[MoonShadows]

can you cut those damaged lily leaves off, then document if any others get damaged as well?

I've been cutting off the damaged ones for 3 weeks now.