PAW PAW DISEASE

Chris starts with ...
Hi i am having a problem with Paw Paw trees the under side of the leaves have black spots,this bug must suck the sap from the leaves and kills the leaf. I have seen this on other trees around Brisbane through out winter.
Any ideas appriciated.
Chris

mike says...
Hi, I'v planted some pawpaws and papinos and they responded beautifully and started bearing a lot of fruit. ALAS...looked forward so much to enjoy it, but they all go limp and soft as a result of what appears to be stung by a fruitfly?? or something, because white coloured sap seems to be oozing out all over the fruit and this desease?? is spreading to all the trees. Please help!!!What can I do to prevent this?

mike says...
No, I haven't noticed any insects or bugs around.

Sue Southwick says...
My paw-paws are wilting and dieing. When I pull them out there main stem has a soft section that collapses. I can see no sign of any insects. The weather has been very hot, have had trouble giving them enough water, but thought they should have survived on what I gave them. We live in Mackay, Qld.

Brendan says...
Hi Sue,
Sounds like too wet to me too? Paw paws don't like a lot of water.

Next time you plant some, dig in lots of composted cow manure (eg moo poo), some dolomite and gypsum. The secret to growing good paw paws is too much mulch.

After they're growing well, say 6 to 9 months, give them some fertilizer like Dynamic Lifter Plus, and some extra Sulphate of Potash, that will make them fruit.

Wayne says...
Sounds like the dreaded die-back fungus Mike. I would suggest to get rid of the tree altogether, make sure you put it in the bin, not to compost

Robbie says...
I have paw trees growing along side of the house and they have black spots on leaves and new fruit. Have just cut off all old growth/diseased leaves and sprayed young ones with white oil. Hoping if I fertilise and mulch them now this will help them pick-up. I have eaten 1 paw paw from these trees and it was delicious so I don't want to loose them.

Marl says...
Hi Wayne
I have a paw paw tree about 8 months old..it is growing beside a shed...all the leaves are a pale green/yellow and are curling up on the ends (the whole leaf is just about closed from the curling)

I have previously grown a paw paw near the spot the new one is planted - and it grew well but the fruit was always bitter so we removed it.

Hope you can help.
Regards
Marl

Wayne says...
Hi BJ
I watched the show to and was a bit surprised about disposing the old plant into compost

Hi Marl
Sounds like you have what the TV show was about. If it was dieback the top of the tree would be stunted and the leaves small, as if something has compressed the top of the tree.

You could have cured that bitter taste with epsom salts and dolomite I think

francis gomes says...
I have a pawpaw tree it is growing good
it bears fruits to about an inch and half
then falls from the tree.
I am located about a quater mile from the sea.could the location be the problem?

Wayne says...
Hello francis
"it bears fruits to about an inch and half then falls from the tree"

Does the fruit yellow before dropping off? If so it could be a calcium deficiency, try spreading dolomite under the tree.

Hello Rob
Try sulphate of potash and then spray with copper oxichloride and mancozeb combo weekly with a wetting agent.
I would also be inclined to spread some dolomite under the tree.
To give your fruit texture and sweeten it spread some epsom salts around. If your fruit is hard spread a smidgen of borax around

Mulch well under the trees

cheers

amanda says...
Nice post Jantina :) I second that.

amanda says...
Hasn't it been lovely! :) It's great to be able to relax on here again.

Jason says...
Foxberry, these Queenlanders are talking about papaya rather than pawpaw, it's a bit of a problem but they are a strange lot up there :D

Julie says...
Multiguard snail pellets are pretty good at knocking off slaters.

If you have mulch around the tree trunk, remove it - slaters love mulch!

francis,when you have a particular problem, it's worth checking the search box at the top, on the right. There are several threads which deal with slaters. It sort of gets lost in a paw paw thread.

Mike says...
I have long had trouble with fungal diseases in paw paws including the black spot one.Mancozeb mixed with copper oxy helps but not against the rot.I had 1200mm in Feb and they struggled. But my solos and aussie reds are re-suckering.The fruit spotting bugs cause bunchy top and I probably spread diseases.Like many fruit sulphur,K,P Mg and particular microelements can improve fruit taste and disease resistance

Wayne says...
Hello Doris
I think your trees suffer from a major Calcium and Potash deficiency which could have in turn encouraged a fungal disease.

I would suggest spreading plenty of Gypsum and Sulphate of Potash around under the trees, plenty won't hurt

A copper spray such as Copperoxichloride is good for the fungal control, sprayed weekly making sure you use a wetting agent. Without the wetting agent it will not work successfully.

I have always used the copper spray with success but, of late, I have been trying Eco-fungicide with Eco-oil as the wetting agent but can't really compare the difference yet. The downside of the copper spray is that it kills flowers such as Mangoes etc if used before they set fruit.

Some of the other guys might help out here with advice on the Eco-fungicide or suggest an alternative

A pink solution of Condy's Crystals [Potassium permanganate] sprayed on the fruit also won't hurt. You can get that from a chemist

Wayne says...
It won't do it any harm Doris but is it necessary if the Lemonade tree is doing OK. Do you know what killed the Orange tree

Wayne says...
Proven remedies are always worth a try Kert, calcium on Pawpaws is essential and gypsum is the best product I know for the job as it doesn't raise the ph level of the soil.

Mike says...
Healthy soil with humus,live soil organisms,colloids and good structure gets all the nutrients to plants better than just having the perfect nutrient blend from fertilisers.Disease resistance is related to this and pesticides can reduce soil health by affecting soil organisms.
Bisexuals often have a ratio of 60 to 20 to 20 of bisexual to female to male offspring

Mike says...
People keep asking the same questions and I have a short memory Wayne and I never cut and paste.

Peter says...
Hi all,
such a trouble in this forum whenever someone seeks help with a sick plant!
From my perspective there is nothing wrong with general statements and will help the person who asks about a problem with their plant. Mike has nice insights about fundamental biological laws, whereas Wayne shares his knowledge from a plant nutrition view. All very valid and helps the person in panic(?) to understand what could be the cause(s) of the problem. Most would probably hope for quick personal advise rather then searching the forum or other sources for someone with a similar problem.

kertt says...
Wayne have you blasphemed my name again? Am I to not respond? Heck no!
Prithee ,that you should avail yourself of the proferred knowledge --- gypsum is useful as a soil conditioner ONLY if there is a sodic clay (look it up if you cannot understand) Potassium deficiency does not occur on clays and is rarely a problem. May I humbly suggest you not respond to things unless you have a genuine insight ,not just a general nostrum.

kert says...
Oh, i do like to delete you sng. Back to the cancer lab! . Who knows what you're on the cusp of discovering!.

amanda says...
This is a very user friendly link on clay soils (it's not technical and it's a small download..) It's great for an intro:

http://www.abc.net.au/gardening/stories/s1676965.htm

Gypsum is not just a 'clay breaker' - it can also used to manage sodicity too (in sandy soils as well). It's a valuable source of soluble sulphur also. It's big advantage is that it doesn't mess with pH. Yes - it can upset relations with other elements - but so can dolomite. There is also the magnesium:calcium ratio to consider here. I will see if I can find a user-friendly link regarding that... Speedy would be able to explain in a flash! Where are u Speedy!? :)
But that's why getting a laboratory soil test done is so incredibly worthwhile when u are starting out - it takes away all this guess work ;-)

When in doubt - use lots, and lots of compost - it's hard to fail with a well made compost, in the interim.

(EDIT: it's easier to explain the calcium:magnesium ratio I think!? It is commonly believed/observed that when a clay soil has more magnesium added to it - it increases it's compaction and 'sealing' qualities (ie: it crusts over) and collapses the clay structure (likely leads to increased slaking too, I guess) But - it has also been 'observed' that this is more likely to occur with an increase in pH also...Dolomite will alkalinise the pH (and add magnesium too) Gypsum does not do this. It's a safer bet in neutral to alkaline soils AND when you do not know the results of the lab testing.

(I mentioned Speedy cos he actually has this type of clay soil :)

And - to be honest - I am still trying to get my head around this one too....the calcium is good for clay soils - up to a point. After that it does just what Mike mentions. I find iron is the first stop on my radar when I have "over done it" (I use gypsum to assist with my big salinity problem...but I have sand - so a bit different...it flushes brilliantly so any negative effects are very transient)
That is my rudimentary knowledge so far... (I'd go for the compost as my first remedy in clay soils to be honest)

Mike says...
Mulch and fertlise with DL and BB I mean.

amanda says...
SG - I pH test everything I import. Sand is more forgiving (I find) and you can get away with a bit more.
What Mike should have done is pumped his clay with organic matter instead of chemical fert's.
Organic matter "opens" clay the same way as gypsum - but without the "chemical side effects" It is the panacea of all soil types - in varying degrees - but clay takes it in vast quantities - better than any other soil type.
Chemical fert's should only ever be a mere tweak in good clay soils with ample organics. Just my opinion tho...sand is vastly different.
The best organic matter is aerobic (hot) compost - always. From a tumbler or a turned heap - whatever - it rules (depending on the ingredients)

Brendan says...
Not a great fan of dynamic lifter fert Mike, not enough P & K for me, and too much N. Best organic fert IMHO is Terra Foska Complete TE, the TE stands for trace elements.
Another good one is Super Growth, it too has trace elements :-)

amanda says...
Seamungus is really nice stuff (a little more expensive) I can't remember it smelling too bad...but it was awhile agao now...

Brendan says...
BJ, there was one called No-Pong from big W, don't know if it's still available tho?

Mike, hard to beat Super Growth for price. A very good fertilizer too.

Brendan says...
Hi amanda,
Super Growth organic fertilizer is made by Katek, don't know where?
It's $32 here for a 35kg bag, stinks a bit but works well, it's slow release.
Yes, like you, I tweak Super Growth with extra P & K for certain trees/plants. Eg, garlic 'should' be fertilized with an NPK fert of 5:10:10 :-) (tomatoes like that brew too).

Forgot to mention, Katek also make a 50/50 fert (synthetic & organic), with an NPK 8:2:6, plus trace elements, it's called Super Grass, but can be used on the veggie garden/trees etc.

Brendan says...
Hi amanda & Mike,
Have a look at: www.katekfertilizers.com.au

Looks like it's made in Gympie Q.

(see, they do spell fertilizer with a 'Z' :-)

Mike says...
Maybe the English and Australians defied convention and changed it to an 's'and it became the norm.I have seen very old English and Australian references that use an 's'.

Brendan says...
Not bad SG! :-)

Steven says...
Hi Pam, it sounds like youve got a fungal infection on your tree, i think ive got the same problem on my papaya trees. The best way to get rid of it would be with a copper fungicide. cut off the worst leaves and spray the whole tree. do this several times over say a month or two and it should pick up.

If you want something kinder, try making a solution of 1 liter of water, two teaspoons of sodium bicarbonate a drop of vegetable oil and dishwashing detergent (im not sure why you need that) the sodium bicarbonate is also a fungicide but its much weaker. however it should do the trick.

Let us know how it goes.

Amateur says...
I recommend Googling 'sulphur deficiency' and researching the importance of sulphur to plants (and humans).

Nick says...
My pawpaw trees seem to have some form of mosiac type disease. The leaves open and then very quickly they seem to develop a colour change and the tips get curly...the plants are not robust and healthy, any suggestions, I have looked for parasites but cannot find any, tried copper based fungicides with no success. We live on the Moreton Bay Islands and we also have citrus trees nearby as well as grapes. Any suggestions?????? Nick

Gordon says...
probably needs a good fertaliser

Cahbundy says...
Hi,
I purchased two papayas over a month ago, and one is growing new leaves which are deformed and curly. The other one is growing normally. Both have received identical care and have been potted up and fertilized regularly with seasol. I have a suspicion that this is a virus, but could someone please advise me what to do to save the healthy one? Thanks in anticipation.

southside says...
my paw paws are close to citrus. they grow wonderfully to a point then seem to go mouldy on the outside, turning black with some white chrystally things on them

Linda says...
Rather late :( but perhaps this will help someone else.... You have pawpaw black spot - it's a fungus.
https://www.abc.net.au/gardening/how-to/pawpaw-protection/10397432