Subject: Question about peach trees

From: [email-masked] (Joseph Wallace)
Date: Wed, 15 May 1996 04:02:14 GMT

A friend of mine has a orchard of different varieties of peaches and
she has noticed that alot of the tree leaves are turning yellow like
it is the fall season.  The only problem is that it is early summer
here. Does anyone recognize this symptom? Is it nematoids or a fungus?
And if someone does know what yellowing leaves mean, how does my
friend treat them?

                                Any help appreciated,

                                              JW

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From: John Lobingier <[email-masked]>
Date: 16 May 1996 04:32:13 GMT

Yellowing could mean different things.  Not enough iron, it's lacking some 
nutrient?, too much water, not enough water. You don't say anything about 
the conditions. 

John

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From: "Curt R. Rom" <[email-masked]>
Date: Thu, 16 May 1996 22:48:17 -0700

Joseph Wallace wrote:
>                                               JW=======================================================================

RE:  Yellowing of Peaches

	In our region, we are experiencing yellowing of peach leaves as 
well.  My diagnosis is attributing the yellowing and early defoliation to 
several circumstances.

1]  Bacterial leaf spot, for which there are really no good control 
measures except resistant cultivars, is very severe this season.  The 
leaves, especially the first leaves to emerge (shoot basal leaves) will 
form spots, which will become shot holes, and then the leaves turn yellow 
and fall.  Our environmental conditions have lead to severe infections on 
susceptible cultivars and even some expression of symptoms on relatively 
tolerant or resistant cultivars. 

2]  Winter Injury.  We had two very severe temperature drops; the first 
around Valentines, and the second on 8-Mar and 9-Mar.  This has lead to 
severe trunk cambium damage.  If you would cut into the lower section of 
a scaffold limb or trunk and remove a chip of wood (1/2 to 1 inch wide, 
into the xylem) if the camibum is discolored to brown/black, you may also 
have winter injury.  We have a tremendous amount of injury but with some 
cultivar variabilty.  On some sensitive cultivars, they leafed out, but 
were all yellow, started to defoliate and wither; we are observing some 
gumosis on lower sections of scaffolds and trunks as well.  I think we 
will eventually loose limbs or trees as they collapse under the 
transpirational stress of the ensuing warm, sunny weather. 

3] Flooding:  We have had very wet soils from spring rains.  Peaches are 
very sensitive to anoxia (flood stress -- lack of oxygen to the roots) 
and will not take up much N as a result.  This will typically result in 
yellow foliage (often with redish margins and veins) which is often 
followed by defoliation.  Likewise, under very dry conditions in the 
spring, N uptake from fertilizers may be limited and the trees appear 
yellow or pale; they will eventually green up. 

4]  Soil pH problems and Fe deficiency.  Fe (iron deficiency) can occur 
in low soil pH (<4.8), high soil pH (>7.5), in soils with high Mg (or 
excessive dolimitic lime applications) or in flooded conditions.  Apply 
foliar chelated iron or the fungicide Ferbam to correct. 

Hope this helps

Curt R. Rom
Professor, Pomology
University of Arkansas
[email-masked]  (see 
http://www.uark.edu/depts/hort/dept/fruitpage.html)