Grapefruit: scale recovery, white bugs, soil fuzz

Discussion in 'Citrus' started by bunni, Dec 8, 2006.

  1. bunni

    bunni Member

    Messages:
    12
    Likes Received:
    0
    Location:
    bc canada
    I've been entrusted with the care of my husband's grapefruit. It's about 5 years old, 1 metre tall. Last year some of the leaves started to yellow, and we noticed it had scale. I pruned a little, and have been spray treating with neem oil every week or two. The scale no longer seems noticeable (haven't found any insects for the last month or so). I'm in the Vancouver area, and the tree normally lives on my north-facing balcony, but I brought it in a couple of weeks ago, during the freeze. The leaves are still quite yellow (I was told that yellow leaves were a symptom of scale), and I noticed tiny (less than 1 mm) little white bugs in the soil. There is also white fuzz (mold?) on the top of the soil. It had its last shower (left it under a running shower for 30 min) about 1 month ago. What do I do about the yellow leaves? Are the little white bugs something to worry about? And about the soil mold (the latter I scraped off)? Also, how do I get it to grow bushy? While flowers would be nice, I'd rather a bushy houseplant.
     
  2. skeeterbug

    skeeterbug Active Member

    Messages:
    826
    Likes Received:
    10
    Location:
    Pensacola, USA
    Pictures of the leaves would help, but without seeing them, yellow leaves suggest a variety of problems. Low nitrogen, iron or various other deficiencies as well as old age can cause yellowing. The pattern of the yellowing however can be useful for diagnosing deficiencies.

    Here is a website that list symptoms of deficiencies. http://edis.ifas.ufl.edu/CH142

    As for the soil problems, what kind of soil are you using? The bugs may be fungus gnats --they like moist soil.

    Skeet
     
  3. bunni

    bunni Member

    Messages:
    12
    Likes Received:
    0
    Location:
    bc canada
    I've attached three photos. One of the tree itself, and two of the leaves - the better and worse leaves.

    As for the soil - I repotted once, and added some all-purpose potting soil from Home Depot.

    Thanks.
     

    Attached Files:

  4. Newt

    Newt Well-Known Member 10 Years

    Messages:
    1,274
    Likes Received:
    2
    Location:
    Maryland USA zone 7
    Bunni, I can't quite tell from the first picture, but the pot it's in looks a bit small. Being rootbound could cause yellow leaves.

    If you are seeing bugs in the soil I suspect you see fungal gnat larvae which could mean overwatering. Either the fungal gnats or the overwatering could also cause yellowing. It truly sounds like it's been overwatered, especially since you had mold on top of the potting soil. Leaving it in the running shower for 30 minutes is way too long. You should water to the top of the pot, let the water run through to the saucer and dump any water after 10 minutes.

    For fungal gnats take a look here.
    http://www.ipm.ucdavis.edu/PMG/r280300811.html

    This is what the larvae look like.
    http://images.google.com/images?svn...0&ct=result&cd=1&q=fungus+gnat+larvae&spell=1

    Btw, it will never be bushy. Grapefruit grows into a tree.

    Newt
     
  5. bunni

    bunni Member

    Messages:
    12
    Likes Received:
    0
    Location:
    bc canada
    Thanks. My shower trick was just to mimic rain (and get dirt off the leaves), I'll definitely let it water out. I just thought it might grow bushier since someone on this forum had a picture of a grapefruit that was quite full. I've since noticed mold growing on the top of all my houseplants. Even the ones that are bone-dry.
     
  6. Newt

    Newt Well-Known Member 10 Years

    Messages:
    1,274
    Likes Received:
    2
    Location:
    Maryland USA zone 7
    Bunni, are you sure it's mold and not residual salts from synthetic fertilizers? If you have continually kept the soil a bit too moist then it could be mold, which would still be there when the soil dries.

    Newt
     
  7. bunni

    bunni Member

    Messages:
    12
    Likes Received:
    0
    Location:
    bc canada
    It could be salt. I haven't added any fertilizers myself, but the growth on the top of the soil did not occur until we moved a couple of months ago. The new place is a little cooler, so the soil takes longer to dry out, but all the plants are on windowsills above baseboard heaters, which ought to help them dry (except they are by windows, which keep them cool).
     
  8. bunni

    bunni Member

    Messages:
    12
    Likes Received:
    0
    Location:
    bc canada
    Nope, I'm not sure it's not salt. But, I've not added fertilizer, and the fuzzies didn't start till we moved. The growth looks fuzzy, and not crystalline.
     
  9. skeeterbug

    skeeterbug Active Member

    Messages:
    826
    Likes Received:
    10
    Location:
    Pensacola, USA
    I think the yellow leaves are indicating a nitrogen deficiency. If you haven't been fertilizing you need to-- use a slow release fertilizer with a 5-1-3 NPK ratio-- Osmocote makes one that is very close to that --something like 19-4-12. With a slow release fertilizer you only need to fertilize every 3-4 months. The tree will aslo need some trace minerals including Mg.

    Overwatering can be part of the problem as well-- the soil need to dry to the touch at least 2-3 inches deep between watering.

    Skeet
     
  10. Newt

    Newt Well-Known Member 10 Years

    Messages:
    1,274
    Likes Received:
    2
    Location:
    Maryland USA zone 7
    Bunni, I agree with Skeeterbug. Lack of nitrogen can cause chlorosis and could be the cause as well. I would still recommend you check to see if it's rootbound. There are citrus fertilizers that can be purchased as well. Here's some growing info on grapefruit.
    http://www.hort.purdue.edu/newcrop/morton/grapefruit.html
    http://aggie-horticulture.tamu.edu/citrus/grapefruit.htm

    Here's info on chlorosis.
    http://plantclinic.cornell.edu/FactSheets/microchlorosis/microchlorosis.htm
    http://www.urbanext.uiuc.edu/focus/chlorosis.html
    http://www.ext.colostate.edu/pubs/garden/07728.html

    Newt
     
  11. bunni

    bunni Member

    Messages:
    12
    Likes Received:
    0
    Location:
    bc canada
    Thanks for that info. I'll look into fertilizers, and I'll repot. I appreciate your help!
     

Share This Page