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View Full Version : Leaves drying, strange discoloration, possible spider mites


MentalFloss
07-01-2019, 08:28 AM
Hello everyone,

I am new to this forum and a noob in gardening overall, but I took the time to try and research my plant's problem, tried different things but no luck.

I have 2 banana plants, 1year old, in different pots and different locations in my appartment. I live near the sea and frequently there is a breeze. During the last 2 months they are on 2 different balconies and before that they were inside. I live in Northern Greece, and our current climate is very hot and humid, with frequent short downpours and highest temp around 35-40 celsius.

The plant which I am showing you was doing very well while inside, but a week before I took them outside I found some spider mites, they looked like tetranychus, with fine webbing all over the leaves and little white-yellowish insects. The other plant was affected as well, but now it's doing just fine after treatment. What I initially did was:
1. Washed both plants thoroughly
2. Cut almost dead/ affected leaves
3. Sprayed with a solution containing green olive oil soap, garlic and alcohol. I have used this before on other cases and it was recommended to me by a proffessional, as a means to avoid chemical pesticides.

The first plant recovered. The plant in question is steadily declining. I can't find any signs of spider mites anymore, but the leaves are drying out. This is the picture on the 21st of June: (Sorry, the forum gallery keeps rotating the picture)
http://www.bananas.org/gallery/watermark.php?file=64824&size=1 (http://www.bananas.org/gallery/showphoto.php?photo=64824&ppuser=30275)

After this, I tried different things. I tried resprayingit with the mixture, I tried not watering ituntil the soil was dry for more than 2-3 inches deep, then I tried fertilizing it + iron, now I am watering it normally. I cut all dying leaves except one, because I think that if I cut it then the plant won't be able to photosynthetize. There is a new leaf growing, but realy slow. I can't see any signs of tetranychus. Today's picture is this:

http://www.bananas.org/gallery/watermark.php?file=64826&size=1 (http://www.bananas.org/gallery/showphoto.php?photo=64826&ppuser=30275)
http://www.bananas.org/gallery/watermark.php?file=64828&size=1 (http://www.bananas.org/gallery/showphoto.php?photo=64828&ppuser=30275)
http://www.bananas.org/gallery/watermark.php?file=64827&size=1 (http://www.bananas.org/gallery/showphoto.php?photo=64827&ppuser=30275)
http://www.bananas.org/gallery/watermark.php?file=64825&size=1 (http://www.bananas.org/gallery/showphoto.php?photo=64825&ppuser=30275)

Your expertise would be gladly appreciated.

Thank you :nanadrink:

edwmax
07-01-2019, 10:33 AM
Likely root rot has already set in. ... But the only way to verify this is to repot the plant and inspect the corm for signs of rot. Which are soft brown/back areas & black roots. A healthy corm and roots are white. ... Also the rot could be caused by insect or other damage and passably internal to the corm ( very bad if so). It is really hard to get a plant over this, but can be done.



To clean remove any soft black areas on the corm and all black roots. Rinse the corm in bleach water to kill any rot fungus (4 or 5 minutes). The fungus will actually draw water from the corm & pstem so we need to kill it. ... Then repot the corm in course sand ( not play sand). Use pool filter sand. Do not water until you see new growth. The dry sand will help to keep any remaining fungus from growing and kill it. ... It any green leaf is remaining, mist it a couple of times per day but no water to the sand.


Be patient, the plant will take a while to recover; 1 to 2 months for new growth.




Now get a long stem moisture meter to check the moist of the potting soil deep in the pot and at the bottom. Soggy poting mix here will start a fungus which will get to the corm. ... I see your pots have a saucer so I assume the pots will drain. If when watering the water doesn't start draining within 15 to 30 seconds or so, the potting mix is to Denise and have too much peat; add more perlite! And do not let the pot drain holes sit in the water.


Now ... Go buy another Nana plant. We've all killed/murdered our first nana plants.

MentalFloss
07-01-2019, 12:45 PM
Thanks for the quick and comprehensive reply!

Buying a new one is no option, the sentimental value is quite big, since I bought the plant from a plantation on the opposie side of Greece, in Crete.

So, I'll try to save it. Just some clarifications:

1. Bleach / water ratio?
2. Alternative to pool filter sand? Would any type of coarse sand do? Would larger stones such as pumice stone do?
3. Watering: I have an automatic dripper system and it never waters the plant that much. So, the water is never enough so as to drain. It gets about 500-700ml / day in this period and the soil is never dry but never soggy . Should I switch to manual watering? Take into consideration that it is very hot during this period.
4. Soil Ph / humidity. Optimal values?

Thank you very much

edwmax
07-01-2019, 02:53 PM
Thanks for the quick and comprehensive reply!

Buying a new one is no option, the sentimental value is quite big, since I bought the plant from a plantation on the opposie side of Greece, in Crete.

So, I'll try to save it. Just some clarifications:

1. Bleach / water ratio? ... about 1/4 cup per gal (3.7 L) Much stronger than general kitchen sanitation. I have poured it on the corm straight from the jug which has a concentration of 5% to 8% for household bleach.


....

2. Alternative to pool filter sand? Would any type of coarse sand do? Would larger stones such as pumice stone do?
Your local building supply should have a course general purpose sand and pool filter sand. The fine sand closes the open pores up enough to be able to hold water within the space. Generally play sand and beach sand is to fine. The sand needs to allow most of the water to drain out.


....

3. Watering: I have an automatic dripper system and it never waters the plant that much. So, the water is never enough so as to drain. It gets about 500-700ml / day in this period and the soil is never dry but never soggy . Should I switch to manual watering? Take into consideration that it is very hot during this period. ...


Now I'm more sure this is a large part of the problem. ... Bananas need FRESH water and do not tolerate stagnate/stale water. The pot need to flush out residual fertilizer salts and other bad stuff. I'm fairly certain you will find the bottom 1/2 of the pot soggy while the top is dry. This infected the roots and the roots carried the infection to the corm. ... A potting soil mix with 50% to 75% perlite and no compost; should be ok for bananas. Watch the peat and compost as they will hold water like a sponge.





....

4. Soil Ph / humidity. Optimal values? Ph.... between 5.8 to6.8 with 6.2 or 6.3 better.


humidity ... Bananas are tropical plants with a high humidity requirement. The humidity of home/Apart is generally too low due to the AC and will dry out bananas. Outside humidity is better than inside but still low. Misting the leaves 2 or 3 Xs a day will help. Raising the pot drain holes above the water in a saucer and allow the water to evaporate for humidity will help. ... Banana leaves are big for a reason. They can take in morning dew and light rains while their roots are competing for any water in the soil. So for this reason foliar feeding fertilizer and misting is great for bananas and a BIG help when the roots are impaired & damaged. Further on hot days the 'in-ground'-banana plants by transpiration can easily deplete the water in their root zone thus daily watering to replace the water in the root zone is needed.



Container bananas need less fertilizer and water than in-ground bananas. Watch the leaves they will tell you when water is needed. Check out the forum wiki for fertilizer & watering info.




Good luck with your plant. I hope you can at least get a pup or two from the corm.