Orange Tree problem - Help Pleeeeaaaase!!!

[Jester]

Hi guys, this is not exactly bonsai related but I would appreciate any help . I have a Washington Navel Tree that I have almost brought back from the living dead for a neighbour . It has improved in leaps and bounds and is over 45 years old. The thing that has upset me a lot in the last two seasons though is that at almost the final stage of fruiting, the skin of the fruit develops brown rashes. The fruit is quite edible and may i say delicious.... the best oranges I have aver had actually. I am "assuming" it is red citrus mite and on that basis I have been using Yates Natrasoap Insect and Mite Killer but perhaps I did not give it enough applications. Maybe I should be using another product.??? The other thought I had is that for an orange tree, the branches are very fissured and although the foliage and fruit are "much" improved perhaps the fissuring (which does'nt see normal to me) is a legacy of the many years of neglect it suffered and the mites not only have had the opportunity to do their own thing, but are still residing there. I'm sorry that this post is becoming so long winded!!!

As a sidebar to this I have noticed that in the past , particularly the italians and greeks paint a white material on the the trunk. Is this sulphur? and if so, does anyone know why? and can / should it also be applied to the main branches?

Many thanks in advance
John

[Hackimoto]

The white paint that the Europeans put on tree trunks is just that, White paint. They believe that it deflects the hot sun from burning the trunks and various other reasons. http://www.google.com.au/search?hl=en&q ... unks+white

The other problem is probably citrus melanose. See link. http://www.google.com.au/search?hl=en&q=melanose+citrus

[Jester]

Thankyou very much Hackimoto

John

[Hackimoto]

You are more that welcome John

[Jester]

Actually Hackimoto, I will go a step further with you since you were so courteous in replying. I found that the tree's fruit is suffering from a condition called "Citrus Scab". There are probably quite a few reasons the tree has contracted this. The solution however (and you may know this already) , is to mix some copper oxychloride (although most copper - based fungicides would probably work), together with an appropriate ratio of white oil. The first treatment should be applied as the flower petals fall, then as the fruit has just started to develop (say half the size of a golfball), and then as the fruit approaches full size. I never really took the time of or even thought to closely examine the twigs and bark of my neighbour's tree but I am guessing it is there too and the instructions on the copper oxychloride state that it can and probably should be sprayed on all parts of the tree. My guess as to why this particular tree contracted such a condition are two fold: As stated previously, the tree had been neglected for along long time and also, the tree is positioned in the corner of a yard where it leans up against a brick wall on two sides, so much so that some of the branches , foliage and fruit lean on it. For this reason the insufficient airflow in my opinion has the spores of this fungal disease to live happily given the amount of humidity that can and does exist. I plan to give it a spray this weekend as a precursor to next year's spray program but have also given it a thinning out to compensate for the lack of airflow.

Where citrus trees have this condition, they will usually drop a lot of their flowers to restrict the amount of fruit that is produced. The fruit that is left will often grow bigger than normal as there are far fewer of them.

I have just taken a picture under my office light from an orange picked from her tree. As I may have stated previously the fruit is perfectly edible.

I work in a wholesale nursery and up until now I did not know anything about this condition. I had also asked 2 growers who specialise in citrus who bring in our orange and lemon tree stock and they had no idea!! Wow!!! I guess, sometimes you just have to go get it yourself!!! Althoug not really bonsai related I hope this info has been valuable to people on the forum.

John

[Hackimoto]

Thanks John, I worked in the nursery industry for twenty odd years in retail. I still think it is melanose but it doesn't matter, as the treatment is pretty much the same. See links:

http://www.dpi.nsw.gov.au/__data/assets ... citrus.pdf

http://www.dpi.nsw.gov.au/__data/assets ... citrus.pdf

[Jester]

Hey mate, on this tree I think it would probably be a combination of both, but yes, point taken.

Regards

John

[Hackimoto]

A rose by any other name etc.