Subject: Re: Orange Tree Problems

From: [email-masked] (DGholston)
Date: 9 Oct 1996 01:08:30 -0400

Subject: Orange Tree Problems
From: "Judith" <[email-masked]>
Date: 8 Oct 1996 17:57:26 GMT
Message-ID: <[email-masked]>

>I have a mature orange tree with the following problem:
>A white, cottony growth on the underside of most of the >leaves.  The
leaves look healty, as does the fruit; hovever >the problem is getting
worse the last few weeks. I would >appreciate any ideas about what it migh
be or what would >cure this.

 Your problem is most likely mealybugs or cottony cushion scale. Is your
plant indoors or outside? Natural enemies normally take care of these
pests on trees grown outside, although ants can spread them and keep
predators away. Spraying the tree with light-medium oils combined with
Malathion should control either pest. Oil sprays alone will also work, but
it may take several applications.

Don Gholston
California Rare Fruit Growers
http://www.crfg.org/

---

From: [email-masked] (Matthew Shugart)
Date: Thu, 10 Oct 1996 13:20:49 -0800

Sounds like giant whitefly.  Not fatal, but you should keep it under
control, as the larvae suck juices from the leaves.  If this is the
diagnosis, you should also notice some black substance--called a sooty
mold--on the upper sides of the leaves.  Anyway, blast the tree frequently
with a heavy spray of water.  Be sure to aim it up on to the undersides of
the leaves.  This will disrupt the flies' life cycles, although it will
not kill enough to give you long-term control.  You can get some control
with horticultural oils or malathion, or even insecticidal soap, but
they'll still be back, so you might just as well use the water spray
(cheaper!).  Supposedly neem extract, the active ingredient in a product
called Green Light Rose Defense, controls whiteflies and is now licenced
for use on fruit crops.  However, the label still says non-fruiting crops
only and I am not 100% sure of the report that it can be used safely on
fruit.  If it can be, it may be the best of all.

But at least use the heavy water spray.  You may need to do it weekly.

In article <[email-masked]>, "Judith"
<[email-masked]> wrote:

> A white, cottony growth on the underside of most of the leaves.  The leaves
> look healty, as does the fruit; hovever the problem is getting worse the
> last few weeks.
> I would appreciate any ideas about what it migh be or what would cure this.
> 
> Thank you very much!
> Brandt