Cycad problem

[fiji jim]

These are our local cycad, C.rumphyii var.seemannii (not sure of spelling).

From pics you can see the leaf damage. We never experienced this until the last couple of years and now it seems impossible to avoid as all plants get the same symptoms. We have applied regular doses of fungicide and systemic insecticide but still we never get rid of this unsightly leaf blotches.

Any remedy would be appreciated.

Jim

[virtualpalm]

Jim, those symptoms look like salt burn. What kind of fertilizer do you use? What is the salinity of the water used to irrigate the plants? Do you add any type of topdress mulch or compost that might be saline?

Jody

[Kris]

Dear Jim

sorry to see those cycads like that...i did have the same problem but in my case i was the catapillers work.but confirm one thing to me dose this happen to the cycas while flushing or this happened to the old leaves.since in my case it was in the flushing stage.and this problem is very common to south asia.

if it happened in the flushing of new leaves stage then contact Jon of eastern nurseries..since he can give you names of the pesticides that has to be sprayed in the flushing period...

since our pesticides names are highly localised,so i cannot help but my problem is solved and iam happy due to jon's help !

thanks & love,

Kris

By the way i had done a entire thread on cycas leaf damage due to catapillers..if you have time kindly search it,since it has lots of stills,and one the cycad that was affected was also the same variety that you have...

[fiji jim]

Thanks for the replies Jody and Kris.

These plants receive the same treatment as all others here and are the only ones that show that symptom.

Recently my workers found a few that had been forgotten for the last couple of years and they were hidden under some overgrown gingers; and they received no water, fert or spray and have the same damage.

Also we have not seen any caterpillar on them.

So it is still a mystery to me.

Jim

[kahili]

Hi Jim-this is one of my favorite cycads, what a bummer for you! I don't know if I can help here, but I have 20 years of commercial growing here in NC and 10 yrs of growing etc in Hawaii-so maybe between us, we can figure it out, if you want. I am pretty familiar with dealing with fungus/insects.

Here are my thoughts:

I googled leaf fungus/cycad and didn't come up with anything. Scale infestations was the most common problem-but you would have seen those. I think any other insect would be visible to your eye, although sometimes a magnifying glass helps.

Instinct tells me that it is a fungus-an airborne one that can spread and thats why the ones hidden in the gingers are showing the same symptoms. I came to this by process of elimination. If it was a soil fungus, I think that you would have started to see some of them dying-esp after a few years-have you? You didn't mention any deaths, so I am assuming not. Also, the ones in the gingers would not have been infected (am guessing they are some distance from the others). If it was high soluble salts burn, the plant would have either died by now or grown out of it. Same with other chemical burns.

I did read one account of a typhoon that was so strong that it burned the foliage of plants far inland with the salt water-does that sound feasible? Most of your foliage is burning/damaged from the tips inward-classic sign of a chemical/salt burn. But looking closely, you can see damaged circles etc closer to the midrib.

So, assuming that it is a airborne fungus, I guess there is no university to send a sample to? I am a big fan of knowing the fungus before I start spraying fungicides, although, as I say-desperation is never pretty! lol I.e-we have all sprayed with educated guesses for fear of it spreading through the crop.

what fungicides have you sprayed on them? How often? Are all these damaged leaves from several years ? Are the new leaves showing these symptoms soon after opening?

Depending on what your answers are-I would be tempted to cut off all of the leaves and dispose of them ( bag them and burn them elsewhere or throw them away) and see what happens to the next flush. These look to be old enough to be established enough to be able to easily recover from taking the leaves off? Sounds drastic, I know, but it may get rid of the spores and these leaves aren't really helping the plant much anymore.

Let me know if anything I said agrees with what you are thinking or whether I missed a piece of info.

Terry

[eastern.nurseries]

Jim, Your problem would appear to be a Lepidoptera and resulting Colletotrichum infection. The egg lay occurs as soon as the plants start to flush, then after a couple of days the larvae hatches, burrows into the leaf and starts to feed, the dead tissue then plays host to the fungus. For further clarification of this problem I highly recommend you join Pestnet. org

Thank you to Kris, I'm pleased to be of some help

[fiji jim]

Thank you all for your concern and ideas regarding this unsightly problem.

I do not believe that salt burn is the problem as no other plants have these symptoms and we have other more sensitive than these cycads. Also I have seen these cycads growing on the most exposed harsh coastal cliffs here with no sign of this damage.

To date we have tried various chemicals to eradicate the problem.

Fungicides used have been ordinary copper spray made from a powder copper sulphate and Dithane M-45 that is 80%w/w Mancozeb and at other times Sundomil which is 640gm/Kg Mancozeb and 80gm/Kg Metalxy. These were applied at two week intervals along with either of these insecticides. Attack which is 47.5gm/lit Pirimiphos-methyl and 25g/lit permethrin or Suncloprid 20SL which has Imidacloprid 20%w/v as an active ingredient.

These are the only available types here that do not cost a fortune.

So today we went the whole way and cut off all the leaves and burnt them and will now see if it reoccurs. Also I will look at Pestnet.org

Fortunately we had sold off about half of the ones we had in stock at the beginning of the year and they were looking OK compared to the ones remaining even though they were located next to each other. Also I believe that the problem has accelerated lately.

If anybody has any more ideas they are welcomed.

[kahili]

So, if eastern nurseries is correct, then you have a moth/worm problem that carries the Colletotrichum gleosporioides that is the causal agent for anthracnose (leaf fungus). That seems fairly easy to take care of.

The Attack should have taken care of moths/butterfly larva. Orthene is also a great insecticide for worms and very cheap. Can you get Orthene, Jim? Acephate is the active ingredient. I would definitely use a surfactant with either and spray the new leaves as they open-once a week for a while ( keeping an eye out for the larva). I think maybe the key is when you sprayed the Attack-the larva could have already hatched and the fungus was in play by then. i would also alternate the two sprays.

Also, for the anthracnose-for me, with annuals, its a very easy fungus to get rid of-esp if you catch it in the beginning stages. It does spread fast and easily from plant to plant as it is a airborne spore. Mancozeb is a good choice, but I think Daconil, although older, is still my first choice for anthracnose and its another that is pretty cheap, although the price has almost doubled. Again-I would use a surfactant with both of these. I would also spray once a week for this fungus-alternating fungicides.

This is from my experience with annuals as the host plant. Cycads may require another fungicide to be effective for anthracnose-but if I were you and this comes up again-I would use the Daconil. I think you did the right thing cutting off the leaves-the anthracnose was too prevelant.

I hope this helps and that the problem is gone now-let me know if you have problems with getting chemicals there. Maybe we can ship them from the states-don't know the regulations for it.

[fiji jim]

Thank you Terry and Jon.

I will see what other chemicals are available and what are the import regulations.

Previously the only import I made was neem oil.

Any experience with neem on this problem. I will try it on one of the cycads that is growing a fair distance from the others and only mildly infested.

Also thanks Kris for alerting these knowledgeable guys of my problem.

Jim

[kahili]

I have never used Neem as a fungicide-and don't think that I would, although I know that some say that it is a fungicide. I think that the anthracnose (assuming that it is that-only a pathology test would say for sure) is more of an issue for you now than the larva. The only way to tell if a fungicide works would be to see if the new leaves are affected-and that takes time with a cycad? How often do these cycads flush for you? the old leaves are going to stay the way they look now. that is kind of frustrating-waiting like you will have to.

I do use Neem some for an insectide-mostly for mites, mealy bugs and whiteflies (mostly to smother the eggs for whiteflies). It may work for the moth larva-if they still are around. Being in the tropics-they may not have a season (and assuming that this is how you are getting the anthracnose-not doubting anyone per say-I just like pathology tests when possible before i start using my chemical arsenal) It would be nice to find out what moth it is also. I just reread what Kris wrote-maybe Kris mentioned the moth that laid the larva in his thread. For me anyway-when I see certain moths around, and they are ones that lay eggs in the particular crop that I am growing, I know to start spraying before I even see any damage.

Generally-when moths lay eggs on a plant-the larva will start to eat that plant for a period of time. Did you ever see any signs of leaves being eaten?

Kris-it still helps if you look at your label of the chemical/pesticide of what you used and say it here-I think that if one knows the active ingredient that you can google it and find it under a brand name that it is sold in other countries. You and Jon both have more experience with this particular fungus/insect problem on cycads and that will help Jim more than the little that I did. I do love trying to solve these problems (esp when I am not the one having them!). They are like puzzles, and you have to get the pieces (info on fert/PH/ weather/watering etc) and see what makes the most sense. I also always learn from them.

[Kris]

I will see what other chemicals are available and what are the import regulations.

Previously the only import I made was neem oil.

Any experience with neem on this problem. I will try it on one of the cycads that is growing a fair distance from the others and only mildly infested.

Also thanks Kris for alerting these knowledgeable guys of my problem.

Jim

Dear Jim

you are always welcome !

Here are few intreasting links to organic fertilizers & pesticides made in south india.i have tried some they all work but are slow release type..

Link !

Kris-it still helps if you look at your label of the chemical/pesticide of what you used and say it here-I think that if one knows the active ingredient that you can google it and find it under a brand name that it is sold in other countries. You and Jon both have more experience with this particular fungus/insect problem on cycads and that will help Jim more than the little that I did. I do love trying to solve these problems (esp when I am not the one having them!). They are like puzzles, and you have to get the pieces (info on fert/PH/ weather/watering etc) and see what makes the most sense. I also always learn from them.

Dear Kahili

I will do so as soon as possible,they are all chenical based pesticides...and they are so powerful that if you do not where eye protection and mask,the vapours keep irriating the eyes & nose !

And i used just 2 drops of that using a ink filler,per liter of water and sprayed using a hand held sprayer,sprayed along the direction of the air flow(Breeze)over the leaf area only and not on the root or soil region if done so that could burn the entire plant.

One is called Roger And the other is Malathion but what its composition is i need some time.but are indeed very effective till the next flush.And yes,i use neem composite too,every 6 to 8 months.it keeps off ants from our pots & ground.

Love,

Kris

[eastern.nurseries]

Jim, Some points to consider. Cycads flush quickly, usually within 4-6 weeks they have produced a lot of new growth. The lepidoptera that predate cycads are many and varied, some are activate at night, some during the day and some all the time. The time from egg lay to hatching can be as short as 3-4 days at your temperatures. The insecticides you are using all require ingestion by the pest to kill it, so it has to feed on the cycad to take in the poison and once it feeds the fungal infection can start. An ovacide will prevent eggs from hatching but must be applied every 3-4 days.

[fiji jim]

Thanks again all,

Now our cycads are the C. skinhead variety but not as bad looking as before.

All affected foliage was removed and burnt and before the burning I found some small eggs and grubs on them.

So we will be vigilant and consistent with our treatments and try some different things and alternate sprays and see what will work best and report that when some regrowth occurs.

This is usually our difficult time of year with pests as plants become stressed with the lack of rain and battering tradewinds.

Later,

Jim

[fiji jim]

Hi All

It has been about 12 weeks now since these cycads were stripped of all foliage.

We stuck to the program and sprayed every week and no sign of damage now.

[fiji jim]

They are looking perfect here about 4-6 weeks since flushing.

Beautiful

[eastern.nurseries]

The effort has been well worth it, excellent result.

[fiji jim]

thanks for your help jon

[kahili]

They look great, Jim! What a beautiful plant. Removing the leaves worked out well in the long run. How long do you think you will have to keep spraying them? I think I would stop spraying one of them and see what happens. It could be that the problem is gone.