Phytophthora root rot in avocados

[ericalynne]

I lost two grated young avocados this year to what I think was phytophthora root rot. I set one out last year and it did well, but this spring it never flushed out and the leaves slowly curled up and fell off and the tree is clearly dead at this point. The other one I put out this sprint and it flushed and then slowly died back. I have googled photos and it does look like root rot. Googled information says there is not much to do about root rot in avocados. I have two more trees to put out and don't want to lose them too. Does anyone have any experience with this?

Erica

[Guanabanus]

Be sure to plant avocadoes in a location with good drainage--- non-mucky, non-puddling, porous soil, or on a slope.  Or make a mound to plant on. 

Or, at first sign of root troubles, drench with Alliette.

[Jsvand5]

I have never tried it, but I have read of some people not even digging a hole for avocado's. They just take the tree out of the pot, set it on top of a ground, and then mound soil around it.

[fruitlovers]

I lost two grated young avocados this year to what I think was phytophthora root rot. I set one out last year and it did well, but this spring it never flushed out and the leaves slowly curled up and fell off and the tree is clearly dead at this point. The other one I put out this sprint and it flushed and then slowly died back. I have googled photos and it does look like root rot. Googled information says there is not much to do about root rot in avocados. I have two more trees to put out and don't want to lose them too. Does anyone have any experience with this?

Erica

Hi Erica, i've lost a lot of avo trees to phytophora, but they were all seedlings. Grafted trees should be on a rootstock that is resistant to phytophora. I've never lost a grafted tree yet here. Nurseries pick old trees that survived here long time and graft on seeds from those. So that is only sure fire way to prevent it. Aliette fungucide may kill the fungus when applied, but unless you are willing to reapply repetedly it will definitely come back. Any tree you plant should be in well draining soil. Avos don't like waterlogged soil.

[CTMIAMI]

Erica is there a chance your are using too much fertilizer or the wrong kind? Small trees usually don't die of root rot. Is anyone in your area having the same problem?  Some times too much fertilizer can burn the root system of a tree.

[ericalynne]

Thanks for all the great information. All the soil around here is well-draining, BUT...when we can have a LOT of rain the water table is high and the water can pool in places and perhaps that did it. The trees were in two different locations; I think I will try the highest ground I have and maybe even put it on top and pile the soil around it, as was suggested.

These grafted trees were from ECHO and did fine while in pots. In fact, one did fine all last year. Fertilizer errors are always possible, but I am quite familiar with fungal wilts and am pretty sure that was the problem.

Mainly I wanted to know if the problem was so widespread that growing avocados in south Florida was not possible.

Thank you,
Erica

[Mike T]

Alliete does not have the prevention or apparent curative power of phosphonate.Because it unctions as a tonic it does not adversely impact on soil fauna.Small and large avos and in fact durians are prone to phytopthera.
Excess fertlizer can mirror the symptoms and even trunk cankers,leaf yellowing and branch die back can take place.
 

[samuel]

had heard something about vermicompost as being efficient against phytophtora on durians which i would like to believe...think that was reprted from some experiments in Philippines

then this products with trichoderma fungi that are said to efficient

and for avocado the use of vegetative clonal rootstocks giving tolerance to the resulting tree. Was aiming to get these cultivars but was not able till now... for this grafting season i have only used a black round type of avocado that is considered here to be a good rootstock, tolerant to diseases. I am kind of skeptical with that technique though since each and every seeds of THE avocado tree said to be...have a different genetic potential...

[JF]

the growers here use agi-fos to combat phytophtora. 1 oz/ 3gal.