21 responses
Justin starts with ... I have just noticed that two of my avocado trees (about 4 years old) have lots of branches with splits in them - it's like the outer layer of the branch has split, and all around it is a white powdery substance a bit like chalk dust. Inside the split, the branch has a brown patch. Otherwise the trees have been healthy up until now, and one is just starting to produce fruit. Any idea what this is, how serious it is, and how to treat it? Thanks.
| About the Author Justin Melbourne 20th January 2012 2:47pm #UserID: 2526 Posts: View All Justin's Edible Fruit Trees |
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| About the Author Peter Perth 20th January 2012 11:59pm #UserID: 5034 Posts: |
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Brendan says... Hi Peter & Justin, for what it's worth, I had an avo branch twice as bad as in the photo. I showed it to Jerry Colby-Williams (from ABC Gardening Aus.) when he was in Mackay. He said, 'your tree has a cold.(?) Spray with Fungus Fighter until it clears up.' Fungus Fighter is copper hydroxide. I use copper oxychloride. Try making a paste with either of these and cover the affected area. It should clear it up. If not, cut it off and burn it, or bin it. | About the Author Brendan Mackay, Q 22nd January 2012 9:15am #UserID: 1947 Posts: |
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| About the Author Mike Cairns 22nd January 2012 2:27pm #UserID: 0 Posts: |
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| About the Author Peter Perth 24th January 2012 6:24pm #UserID: 5034 Posts: |
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Brendan says... Have to agree Peter, it would be very interesting under the bark. It looks like either Dothiorella Canker or Phytophthora Stem Canker, mine was the latter I suspect. Because we had a ship-load of rain when my seed-grown 35 year old avocado tree had this, it ended up dying :-(
| About the Author Brendan Mackay, Q 25th January 2012 10:08am #UserID: 1947 Posts: |
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Peter says... Yeah, if we can distinguish between Dothiorella and Phytophthora it would be very good. Both require different treatments. Even Phytophthora is often called a fungus, this is not the case (more related to a group of algae) and will therefore not respond to fungicides. But it will to Phosphite. Application of both at the same time is not recommended. I straight away believe that Mike have seen the same, but it did not cause problems for him - soils in Queensland are in general very suppressive to Phytophthora (if soils are not waterlogged during warm weather). However, the same disease can be more severe in Melbourne soils - they certainly are more in WA compared to Queensland! So still we need to establish if Dothiorella or Phytophthora. | About the Author Peter Perth 25th January 2012 11:08am #UserID: 5034 Posts: |
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Robert says... I have a Haas tree and the leaves are turning brown and crispy I was told that maybe it had to much salt. So I repotted it today and found the soil was very wet. While repotting I tore half the roots getting it out of the plastic pot that it came in. How much did I hurt this tree or do they bounce back. Thanks for any help
| About the Author Robert Corpus Christi Tx 25th January 2012 1:42pm #UserID: 6453 Posts: |
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amanda says... Gee Robert - that doesn't look too good :( One of the Avocado folk here may have some good advice. Dilute Seasol is useful to help with any transplant shock? I wouldn't give it any other fert's just yet - maybe wait till u see some new shoots and then try a little blood and bone. Hopefully it will recover. It might just be a waiting game now. Avocados hate salt - so ask the guys here what they use for fertilising in pots? (ps - have u been overwatering it? It may also have developed a root rot.. :( | About the Author amanda Geraldton, 400km North of Perth 25th January 2012 3:41pm #UserID: 2309 Posts: View All amanda's Edible Fruit Trees |
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Mike says... I didn't want to use the P word.It often manifests as yellowing,loss of turgor and dying of limbs in avos with trunk cankers sometimes forming.In NQ avos in wet areas are pretty prone and it can be an absolute shipfight every wet season.All the same I have seen that condition and just assumed it was not P.The response to fungicide may have been coincidental in cases I've seen. | About the Author Mike Cairns 25th January 2012 7:21pm #UserID: 0 Posts: |
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| About the Author Peter Perth 25th January 2012 7:33pm #UserID: 5034 Posts: |
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Mike says... Peter,by P I mean Phytophthora and avos struggle here every wet season on the coast.The similar problem on my avos which cleared after coppy oxy/mancozeb coincided with the end of the wet season.Perhaps it was phytophthora with different symptoms to that of avo trees that I have seen die of the affliction.If there is any doubt pretty regular phosphite application might be one of the only courses of action. | About the Author Mike Cairns 25th January 2012 8:00pm #UserID: 0 Posts: |
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Peter says... Thanks, Mike. Could be that you cleared up only the secondary invaders feeding on the dead tissue caused by Phytophthora (which as a primary invader moves on to more intact tissue) and the end of the wet season was certainly better to get rid of these fungi. Maybe though it was Dothiorella. I was thinking of P. citricola, which has different symptoms to P. cinnamomi and does not necessarily cause tree death. One of the weird things of this forum when it gets to diseases is that the original enquirer disappears, whilst contributors entertain themselves. By the way: thanks Brendan for the pictures. | About the Author Peter Perth 25th January 2012 9:25pm #UserID: 5034 Posts: |
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Mike says... That could be the case Peter and the Phytophthora may have been cleared by subsequent and repeated doses of yates ant-rot.There could be a low level of 'infestation'in many trees waiting for a trigger.In the absence of the original enquirer giving more info. it isn't such a bad thing to speculate and share relevant experiences. | About the Author Mike Cairns 25th January 2012 9:40pm #UserID: 0 Posts: |
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Peter says... Yes, overall a good share of experiences on a daily (daleys) basis... It feels a bit risky sometimes to speculate though, some just wait out there to get you, if you're wrong. For Robert: Amanda summed it up well - and hopefully it was just salt stress. Just keep an eye on it and keep it less exposed to direct full sun while the plant adapts with being transplanted | About the Author Peter Perth 26th January 2012 12:18am #UserID: 5034 Posts: |
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amanda says... Hey Peter..I'm glad u said that - the first thing I always do with a sick plant (if in a pot) is get it out of direct sun (if summer) - stressed plants just don't need the extra stress of even more fert's and hot/direct sun? I would be interested to see if this plant survives actually....(if it were something more robust maybe) do u think Peter? I agree tho - sometimes it just a waiting game. It can be really hard to speculate on just a photo too..so many variables. I am not sure that people should expect definitive advice here, myself. The forum has become a bit of a "problem solver" over the last cupla' years...I am not sure that was it's original intention? I am very loathe to offer advice on mature trees, for eg, myself. I am not a professional by any means (and don't carry indemnity insurance! lol..) | About the Author amanda Geraldton, 400km North of Perth 26th January 2012 12:48am #UserID: 2309 Posts: View All amanda's Edible Fruit Trees |
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Brendan says... Hi Robert, our garden guru here was asked a similar question as yours not long back, here's the Q & A's. Q. Avocado tree lost leaves & was dying but recovered after a few heavy doses of copper oxychloride solution. Now new leaves are beginning to brown & burn at the tips, what could be the problem? A. Apply Claybreaker to the soil, this is a liquid. 250mls to 4.5 litres of water apply three times seven days apart. This will displace any toxins. (She then explained it was growing in sandy soil) So Tom replied: Most likely salt injury, apply Gypsum four clenched handfuls per sq metre around the area, this will be required twice per year. | About the Author Brendan Mackay, Q 26th January 2012 11:40am #UserID: 1947 Posts: |
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Justin says... Here are some more pictures. So far I have treated with Bicarbonate of Soda and Manuka honey - until I can get the chance to get some Copper hydroxide. There has been a little improvement, but not major as you can see. We also had a hailstorm on Christmas day - not sure if the splits were caused by the hailstones and this is an infection of those injuries, or whether the splits were caused by disease.
| About the Author Justin Melbourne 28th January 2012 3:31pm #UserID: 2526 Posts: View All Justin's Edible Fruit Trees |
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| About the Author amanda Geraldton, 400km North of Perth 29th January 2012 12:06am #UserID: 2309 Posts: View All amanda's Edible Fruit Trees |
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| About the Author Peter Perth 29th January 2012 1:18am #UserID: 5034 Posts: |
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amanda says... hey Peter - will the damaged areas just get re-infected though? I was always under the impression that diseased, damaged and dead branches should always be pruned on any trees...? (not disagreeing with u guys - just curious :) (pic 2 looks particularly nasty - will the tree be able to heal a wound like that..?) | About the Author amanda Geraldton, 400km North of Perth 29th January 2012 11:52am #UserID: 2309 Posts: View All amanda's Edible Fruit Trees |
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| About the Author Justin Melbourne 29th January 2012 1:11pm #UserID: 2526 Posts: View All Justin's Edible Fruit Trees |
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