Hazera Tomato News 5 - Email: [email protected]

TomatoNews
DECEMBER 2009 - issue 5
Your source of information from the world of Hazera tomatoes
Attention: The information contained herein presents average results of specific trials done by Hazera, it is neither exhaustive nor necessarily
accurate and may not be regarded as advice, guidance, recommendation, representation or warranty. Actual yield and varietal performance
may vary greatly due to numerous factors, especially growing conditions & crop management. No warranty is given, whether as regards yield,
merchantability, fitness for a particular purpose or otherwise. Pictures are illustrative and not of product. The sale & use of seeds are subject
to the terms and limitations on warranty & liability appearing collectively in printed catalogue, on seed package and at the following address:
http://www.hazera.com/english/terms.asp E&OE. © Hazera Genetics Ltd. All rights reserved.
Giraff Visual Communications/ www.giraff.co.il
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TomatoNews
2
Your source of information from the world of Hazera tomatoes
From the editors
3
Tomato News
4
LED-lights in tomatoes: near future or just a dream?
5
Summersun: a small step in a very hi-tech world
5
New from Hazera: Magnetic & Ornela
6
Deficiencies in Tomatoes Crops
7
The Road to Success - Shanty & Galilea
8
Ask George - Q&A from the Field
9
Recipe of the Month - Tomatoes Stuffed with Goat Cheese
Appendix - Deficiencies in Tomatoes Crops
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11-12
From the editors
Welcome to the winter issue of Tomato News!
Dear friends,
Now that the crop in already in the ground it is time
to look ahead. Tomatoes are susceptible to mineral
deficiencies, as you are well aware, so we have
compiled a very detailed review aimed at helping
you indentify deficiencies and overcoming their
damage.
In our continuing voyage around the globe of
tomatoes we bring you some stories from the hi-tech
tomato region of the Netherlands. We continue to
follow tomato news around the world and bring you
highlights to help you prepare for the season.
During the past months, you have continued to send
George your questions regarding tomato growing and
production ([email protected]).
George had already answered your questions
individually, but in this issue we are bringing you the
more general questions and answers that may be of
interest to some of you.
We hope you will find this issue as interesting and
useful as the previous ones.
We will be happy to include you in our mailing list,
so you can receive Tomato News directly. You can
register at [email protected] or register via
our website, at www.hazera.com.
Please send us your insights, thoughts and
questions to [email protected]. And if you
have any technical questions George will be waiting
at [email protected].
We wish you all a happy and prosperous holiday
season.
Chief editor: Dr. Alon Haberfeld
Producer: Nilly Maik
Members of the editorial staff: Yaron Giras, Matti
Sarfatti, George Arraf, Meirav Ron, Hadas Amit.
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Season’s Greetings
We at Hazera Genetics wish all our partners and friends
a joyful holiday season and a happy new year
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TomatoNews
Tomato export from Mexico to USA is
expected to grow
The “Tomato Suspension Agreement” signed between Mexico
and the United States in January 2008, virtually binds Mexican
exporters to sell in the United States at or above the applicable
reference price. The reference price for exporting fresh
tomatoes for the summer season (July 1-October 22) is 17.2
cents per pound, and the reference price for the winter season
(October 23-June 30) is 21.69 cents per pound.
Mexican tomato producers export 900,000 tons to 1 billion
tons of fresh tomatoes to the United States every year. This
is almost 20% of the Mexican tomato production. This figure
is expected to increase slightly in 2009-2010 since with the
weakening of the Mexican peso prices become even more
compatible.
The agreement has not had much influence since even with
surplus tomato supply in early 2009 prices were well above
the reference price. (Source: http://fructidor.com/news/
mexico-the-world-s-largest-exporter-primarily-ships-tothe-u-s--6941.aspx)
The tomato import season starting
Polish importers started trading in imported tomatoes in the
past weeks. This came after an increase in domestic tomato
prices on November, with a wholesale price of 10-13 PLN
(2.34-3.04 Euro) for a carton of 6 kg of tomatoes. High quality
tomatoes were priced even higher at 16-21 PLN (3.75-4.92
Euros). First imported Spanish tomatoes appeared on the
market on mid November at prices 18 PLN (4.38 euro for
a carton of 6 kg of tomatoes. (Source: http://fructidor.
com/news/season-for-imported-tomatoes-will-startsoon--7551.aspx)
The moment of truth
for Canary Island growers
This season is important for growers and exporters of lettuce
and tomatoes in the Canary Islands. The last two seasons were
difficult as a result of rising transport costs, rates of exchange
and quality problems. Steve Cornwell of SpanishFresh calls
this season: “The most important ever. Last year our supply
coincided with that from Spain and Morocco and that caused
oversupply”. (Source: http://www.freshplaza.com/news_
detail.asp?id=53754)
* See notice on Page 1
Agrexco tomato shipments underway
The export season has just got underway for Israeli exporter
Agrexco’s organic on-the-vine tomato, sold under its Carmel
Bio-Top brand.
These tomatoes are grown mainly in the Arava region, but
also in west Negev and north of the Dead Sea.
Agrexco points to its tomatoes’ quality and safety standards,
in addition to the health benefits of tomatoes in general,
thanks to their high content of vitamin C, vitamin A and the
antioxidant lycopene.(Source: http://www.fruitnet.com/
content.aspx?cid=4661&ttid=8&sid=97)
Dutch exports reach new record
The Dutch tomato export, which is beginning slowly this year,
looks likely to reach a new record. Most noticeable is the rise
in exports to Mediterranean countries such as Italy, Spain and
Greece. Up until week 32 in 2009 there was 452 million kg of
Dutch tomatoes exported. That is 8.5% (around 35 million kg)
more than this period last year. Out of the most important sales
markets, Russia is the only one who is still clearly importing
less than last season. (Source: http://www.freshplaza.com/
index_region.asp?region=5)
First Report of Tomato Torrado virus
in Tomato Crops in France
In June 2008, tomato plants cv. Fer De Lance (De Ruiter
Seeds) grown in greenhouses near Perpignan (southern
France) showed growth reduction and necrotic lesions on
fruits, stems, and basal parts of the leaves.Tests performed
by local laboratories revealed the presence of ToTV.
ToTV has been already reported in Spain, Poland, Hungary,
and Australia, but this is the first report of ToTV in France.
Further testing in April 2009, of plants from the same
area, revealed 7 positive tomato plants of 17 tested. This
observation suggests the persistence of the disease in the
Perpignan region. (Source: http://apsjournals.apsnet.org/
doi/abs/10.1094/PDIS-93-12-1352C)
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LED-lights for tomatoes:
near future or just a dream?
5
By - Céline De Baere Tomato Product Specialist Nickerson Zwaan
Lemnis Lighting B.V.
More and more growers are testing led-lights for tomatoes, mainly
to try to reduce energy costs. Depending on the lighting system
used, the saving can range from 35% to 50% and maybe even
more. LED-lights for tomato have been tested in North West
Europe for two seasons, and now is a good time for an initial
summary.
It is a well-known fact that plants have better assimilation under
specific wavelengths. Tomato plants need more red and blue
light then other colors. And since with better assimilation higher
yield can be achieved, and leaves use red light more efficiently
for photosynthesis, in theory up to 20% more yield is possible.
However, during the first two years of trials, the average yield
increased by only 5% yield. Apparently, the theory is applicable to
a single leaf, and the result is different for an entire crop. On top of
that, when an entire plant is involved, transmission of assimilates
to their growing points is also an important factor.
Two main points limit the use LEDs for tomatoes - efficiency and
costs. The efficiency of LED-lamps needs to be improved and
the cost must be compatible with conventional lighting system. A
combination of energy saving with extra yield will make LED lights
a winning technology in greenhouse tomato production.
More information is still needed before we can say that LED is
an established technology. Questions such as how to combine
LED and non LED lights, the consequences of uncoupled heat
radiation, PAR-light and far red light as well as coping with lower
plant temperature must be investigated further.
LED emits almost no heat. This is why it can be placed inside
the canopy, delivering the light exactly where it is needed much
closer to the plant. And we also don’t “steal” any sunlight, like
normal artificial lights (SON-T lights) do.
Summersun: a small step in a very hi-tech world
Hazera Genetics launched Summersun in The Netherlands in the winter of 2008. Summersun
is avery exclusive tomato: a yellow cherry with an extremely high brix level. This winter
two Dutch growers are growing SummerSun. Aad en Bas van Leeuwen is growing
Summersun for the third year in a row, and has almost 2 ha. He specializes in a
mixed pack, with 2 or 3 varieties, and uses SummerSun as the yellow variety.
Greenco, that is well-known throughout Europe for their Tommies, initiated a new
Summersun concept with 1.4 ha. The most important reason to grow Summersun
is its premium taste. We hope to bring you more information about SummerSun
in our next Tomato World.
* See notice on Page 1
New
from Hazera
6
Magnetic
Trial Data*
Magnetic is a very productive indeterminate variety for loose harvest, suitable for
a short cycle production (6-8 clusters). This variety is unique due to its compact
and strong plant, early maturation, big size and high quality fruit. Magnetic will be
launched in winter 2010 in China, and is trialed in various markets.
Fruit
Plant
Fruit type – Globe
Av. Weight – 200-270 gr.
Av. Size – 70-80 mm.
Color – intense red
Shelf life – very long
Firmness – very firm
Shoulders – uniform
Vigor – regular
Maturity – early
Internodes – compact
Growing system – indoor
Picking – single
Resistances:
Vd, Fol (races 1 and 2), ToMV, Mj**, TSWV
Ornela
Trial Data*
Grape-cherry tomatoes are becoming more and more popular among cherry
consumers throughout the world. Over the past few years, we have seen consumers
shifting from round fruits to elongated ones. Hazera believes that in several years
this tomato slot will become an important segment of the market.
Hazera is launching a new variety of grape-cherry tomato which is TYLCV Root-knot
Nematodes (Mj) and Tomato Spotted Wilt virus resistant, combined with high yield
and high fruit quality. Ornela will be launched in Spain and Italy in winter 2010.
Plant
Vigor – medium- strong
Maturity – early
Internodes – medium
Growing system – Indoor
Picking – single
Resistances:
Fol (races 1), ToMV, Mj**, Pst, TSWV, TYLCV
* See notice on Page 1
** Soil temperature above 27°C and other stresses
may cause resistance to break
Fruit
Fruit type – grape cherry
Av. Weight – 20-25 gr.
Color – intense red
Shelf life – good
Firmness – good
Shoulders – uniform
Deficiencies in Tomatoes Crops
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By - Yaron Giras & Dr. Alon Haberfeld Tomato Product Managers [email protected]
Visual symptoms of nutrient deficiency can serve as a very powerful diagnostic tool for evaluating the nutrient status of
plants. However, a single visual symptom is often not sufficient to make a definitive diagnosis of a plant’s nutrient status.
Many of the classic deficiency symptoms such as tip burn, chlorosis and necrosis are characteristically associated with
more than one mineral deficiency and also with other stresses that by themselves do not indicate any specific nutrient
stress. However, their detection is extremely useful in making an evaluation of nutrient status. In addition to the actual
observations of morphological and spectral symptoms, knowing the location and timing of these symptoms is a critical
aspect of any nutrient status evaluation. Plants do not grow in isolation, they are part of the overall environment and as
such they respond to environmental changes that affect nutrient availability. Also, plants do influence their environment
and can contribute to environmental changes, which in turn can affect the plant’s nutrient status.
Visual Symptoms
Descriptions of Symptom
Environmental Associations
Please see Deficiency symptoms for your use and convenience
in the appendix at the end of the newsletter (page no. 11).
Stresses, such as salinity and pathogens, induce their own
characteristic set of visual symptoms. Often, these symptoms
closely resemble those of nutrient deficiency. Pathogens often
produce an interveinal chlorosis, and salinity stress can cause
tip burn. Although at first these symptoms may seem similar in
their general appearance to nutrient deficiency symptoms, they
do differ in detail and/or in their overall developmental pattern.
Pathological symptoms can often be separated from nutritional
symptoms by their distribution in a population of affected plants.
If the plants suffer from nutrient stress, all plants of a given
type and age in the same environment tend to develop similar
symptoms at the same time. However, the stress is the result of
pathology, the development of symptoms will have a tendency
to vary between plants until a relatively advanced stage of the
pathology is reached.
Plants remove substantial amounts of nutrients from the
soil during their normal growth cycle and many long-term
environmental changes occur as a result of this process. Effects
on the soil go considerably beyond direct removal or depletion
of nutrients. Charge balance must be maintained in the plantsoil system during nutrient uptake. For example, when plants are
fertilized with ammonia, they acquire most of their nitrogen in the
form of the ammonium cation, rather than from the usual nitrate
anion. Because nitrate is the only anion used by the plant in large
amounts, the immediate effect on the soil may be favorable for
some plants, especially acid-loving plants, since it tends to make
iron more available. However, in the long run, lowering the soil
pH can be harmful to plants due to change in the availability of
nutrients.
A lower soil pH will allow micronutrients to be more readily
leached from the soil profile, eventually resulting in deficiencies
of nutrients such as Cu and Zn. Additionally, when the soil pH
drops much below pH 5, the solubility of Al and Mn can increase
to such an extent as to become toxic to most plant growth.
Plants are often thought of as passive in relation to the
environment. For example, iron is a limiting nutrient in many
agricultural areas, but it comprises about 3% of the average soil,
which, if available, would be far in excess of the needs of the
average plant. Some plants actively excrete protons, and the
resulting decrease in pH increases the solubility of iron, in their
environment. In addition, other plants excrete phytosiderophores
that chelate the soil iron rendering it a more available form for
the plants.
* See notice on Page 1
It is unusual to find any one leaf or even one plant that displays the
full array of symptoms that are characteristic of a given deficiency.
It is thus highly desirable to know how individual symptoms look,
for it is possible for them to occur in many possible combinations
on a single plant. Most of the terms used below in the description
of deficiency symptoms are reasonably self evident; a few however
have a distinct meaning in the field of nutrient deficiency. For
example, the term chlorotic, which is a general term for yellowing
of leaves through the loss of chlorophyll, cannot be used without
further qualification because there may be an overall - chlorosis
as in nitrogen deficiency, interveinal - as in iron deficiency, or
marginal - as in calcium deficiency. Another term used frequently
in the description of deficiency symptoms is necrotic, a general
term for brown, dead tissue. This symptom can also appear in a
variety of forms, as is the case with chlorotic symptoms.
Element and Sufficiency Range
Nitrogen (N)
Phosphorus (P)
Potassium (K)
Calcium (Ca)
Magnesium (Mg)
Manganese (Mn)
Iron (Fe)
Boron (B)
Copper (Cu)
Zinc (Zn)
4.00-5.00% (in Young plants)
3.50-4.00% (in Older plants)
0.50-1.00%
3.50-5.00%
0.90-1.80%
0.50-1.00%
50-500 ppm
50-300 ppm
35-60 ppm
8-20 ppm
20-100 ppm
The Road to Success
Shanty & Galilea
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By - Yaron Giras Tomato Product Manager [email protected]
For two years, Shanty and Galilea have been Hazera’s leading determinate Roma
varieties, selling over 120 million seeds per year and growing fast. I would like to take
this opportunity to share their story with you.
Shanty was developed by our tomato breeder Dr. Ron Ecker
in Florida 2004. From the very first time we saw this variety we
knew that it was a winner. I remember walking in a tomato trial
field in FL in 2005 and stopping at one of the plots. “Hey, what
do we have here?” I asked Ron “You’ve got to see this one! “.
This was the moment we understood we have “hit the jackpot”.
Then came excellent results in Israel and other regions. The
combination of very high yield with very good heat setting
and extremely high TYLCV resistance made the variety an
instant success. We started to sell Shanty throughout Central
America, South America and other counties in the Middle
East. Wherever we tried it, Shanty became the first choice
of the farmers. In one of our meetings with Mr. Omar Zidan,
one of the most valued professionals in the Israeli agricultural
community, he told us that in a recent visit to Honduras he saw
a very productive tomato field “one of the best tomato fields
ever!” according to the grower. This field was Shanty.
Today Shanty is one of the most successful TYLCV
resistant, determinate Roma varieties in the world!
For the past several years Shanty has been selling
over 100 million seeds per year, at a value of over 1.25
million Euros.
Shanty
Galilea
Galilea was developed in Mexico by our tomato breeder
Mr. Ezri Peleg. Galilea was developed for the very harsh
growing conditions of Central Mexico, in the area of Sun
Luis Potosi. The development continued for more than 6
years, and came after the release of several other varieties
in the segment. From the first moment we saw this variety
in trials, we knew that we have found the best Roma tomato
variety for the Mexican market, and possibly one of the best
determinate Roma tomatoes in the world! Galilea combines
extremely high fruit quality with a strong plant and a very
high yield. This makes it “a grower’s dream come true.” We
started to sell Galilea in Mexico in 2007 and today it is sold
in USA, Brazil, Israel and Peru. Sales reached 20 million
seeds (0.4 million Euros) in 08/09 and are forecasted to top
35 million seeds in 09/10 (0.6 million Euros).
We are sure that Galilea will be one of our top varieties
in the coming years and a very successful one too!
* See notice on Page 1
Ask George – Q&A from the Field
George has been active in the field of agriculture for 32 years, 13 of them at Hazera. Before
George joined Hazera, he worked in the field of vegetable cultivation and plant protection
at the Israeli Ministry of Agriculture. George has a graduate degree in Plant Protection.
The primary crops George dealt with are tomatoes, melons, watermelons, onions and leaf
plants. George’s primary field of expertise is the examination of new varieties during the early
cultivation stages, and their modification for the relevant cultivation regions and countries.
Over the past 3 years George has served as the Product Promotion manager for tomatoes in
the major target countries for Hazera tomatoes. Based on his extensive and rich experience
in tomato crop cultivation methods, fertilization, irrigation and plant protection, George is
happy to put the knowledge he has acquired over the years at your disposal.
We invite you to send George any questions you may have about growing tomatoes to:
[email protected]
Question:
I heard about a new disease in tomatoes –
Torrado. Can you explain what it is? How it is transmitted and
how can we, tomato growers, avoid it?
George:
Tomato Torrado virus (ToTV) is a new aphid
mediated virus that was first identified in Murcia, Spain six
years ago, and was later found in Brazil and Mexico. Torrado
symptoms can appear on fruits and leaves, and in the latter they
are very similar to TSWV (Tomato Spotted Wilt Virus) symptoms
- “burned”, brownish leaves in the upper part of the plant. The
burning starts in the middle of the leaf, and after a Torrado attack
no more fruits will set on the infected plant. Due to similarity of
symptoms, TSWV and Torrado are easily confused. However,
since Bemisia Tabacci is the vector transmitting Torrado, and
aphids transmit TSWV, the presence of the vector in the infected
field can point to the virus. You can also use field diagnostic tools
that will tell you which virus you are dealing with. To prevent
Torrado we must protect plants from the vector– the white fly either using physical barriers or preventive chemical treatments.
The virus can attack tomatoes at all the stages, so keep looking
for early symptoms and treat your crop accordingly. No Torrado
resistant varieties are available at present, but Hazera is testing
resistant material and will soon release resistant varieties.
Question: What is the difference between long shelf life
and firmness? Can a tomato be firm without having LSL genes?
Is there any relation to green shoulders?
George:
LSL refers to the long shelf life of the tomato
fruit, while “Firmness” refers to the attribute of the fruit when
harvested. Firmness is a general characteristic of the tomato
fruit, while in order to achieve long shelf life in tomatoes we
must use specific tomato genes that inhibit fruit ripening. Genes
such as NOR or RIN were introduced by classic breeding into
commercial tomato varieties from their wild relatives into the mid
80s. These genes can increase shelf life of harvested tomatoes
from 6-7 days to over 21 days.
* See notice on Page 1
There is no relation between LSL or Firmness and green
shoulders. Green shoulders is a different genetic characteristic,
caused by a different naturally occurring gene (G), which causes
a differential ripening of different parts of the fruit.
There are LSL tomatoes with and without green shoulders, and
they can all have different levels of firmness. You just need to
pick the right variety.
Question: Do LSL and firmness reduce tomato flavor?
George:
Even though tomato flavor is a combination of
taste and aroma, derived from over 400 volatile compounds,
we usually describe it as the balance between the fruit’s
sweetness and sourness. When tomato fruits ripen, at about
the time they turn from pink to red, sourness is at its maximum.
Then, sourness starts to decrease and sweetness increases
due to sugar accumulation. This process will continue as long
as the fruit is on the plant. When harvested, the fruit will continue
to accumulate sugars, but at a much lower rate. Here is the
dilemma – if we let the fruit stay on the plant, we can achieve
higher sugar content, however, we decrease its firmness (since
mature fruits loose firmness over time). If we pick the fruit at an
early stage, we have better firmness but lower sugar content.
On top of all that, LSL genes add sourness to the fruit and
reduce the rate of sugar accumulation, so LSL varieties are
usually less tasty, but with much better shelf life. If you keep
your LSL tomatoes on the plant till they are fully red, you let
then accumulate more sugar and can improve your sweetness/
sourness ratio, thus producing a more tasty fruit.
Isn’t life complicated? Low taste in LSL tomatoes is not a given.
Once you decide what is more important, LSL or taste, you can
achieve very tasty LSL tomatoes.
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Recipe of the Month
Tomatoes Stuffed with Goat Cheese
Preparation:
Ingredients
1. Blanch one of the tomatoes in boiling water for few seconds.
• 3 Hazera Boutique tomatoes
• 8 oz goat cheese
• 1 tsp. chopped garlic
• 2 tbs. extra virgin olive oil
• Sesame seeds
• 4 purple basil leaves
• Salt
• Black pepper
2.Peel and seed the blanched tomato.
3.Place the peeled tomato, goat cheese, garlic, olive oil and a
pinch of salt and black pepper in a food processor, mix until
smooth and red in color.
4.Place the sesame seeds on a flat plate and roll a spoon full of
the goat cheese mixture in them.
5.Cut the other tomatoes in half lengthwise and place a basil
leave on each half.
6.Place the sesame seed covered goats’ cheese rolls on top of
the basil leaf.
7. Serve cold with fresh bread.
* See notice on Page 1
10
Appendix
Deficiencies in Tomatoes Crops
Deficiency
Magnesium
Manganese
Molybdenum
Nitrogen
Phosphorus
Sulfur
Symptoms
Mg-deficient leaves show advanced interveinal chlorosis, with necrosis developing in the highly
chlorotic tissue. In its advanced form, magnesium deficiency may superficially resemble potassium
deficiency. In the case of magnesium deficiency the symptoms generally start with mottled
chlorotic areas developing in the interveinal tissue. The interveinal laminae tissue tends to expand
proportionately more than the other leaf tissues, producing a raised puckered surface, with the top
of the puckers progressively going from chlorotic to necrotic tissue.
These leaves show a light interveinal chlorosis developed under a limited supply of Mn. The
early stages of the chlorosis induced by manganese deficiency are somewhat similar to iron
deficiency. They begin with a light chlorosis of the young leaves and netted veins of the mature
leaves especially when they are viewed through transmitted light. As the stress increases, the
leaves take on a gray metallic sheen and develop dark freckled and necrotic areas along the veins.
A purplish luster may also develop on the upper surface of the leaves.
These leaves show some mottled spotting along with some interveinal chlorosis. An early symptom
of molybdenum deficiency is a general overall chlorosis, similar to the symptom of nitrogen
deficiency, but generally without the reddish coloration on the undersides of the leaves. This is a
result of the need for molybdenum in the reduction of nitrate, which must be reduced prior to its
assimilation by the plant Thus, the initial symptoms of molybdenum deficiency are in fact those of
nitrogen deficiency. However, molybdenum has other metabolic functions within the plant, and hence
there are deficiency symptoms even when reduced nitrogen is available. At high concentrations,
molybdenum has a very distinctive toxicity, symptom the leaves turn a very brilliant orange.
The chlorotic symptoms seen on a leaf are the result of nitrogen deficiency. A light red cast can
also be seen on the veins and petioles. Under nitrogen deficiency,the older mature leaves gradually
change from their normal characteristic green appearance to a much paler green. As the deficiency
progresses these older leaves become uniformly yellow (chlorotic). Leaves approach a yellowish
white color under extreme deficiency. The young leaves at the top of the plant maintain a green but
paler color and tend to become smaller in size. Branching is reduced in nitrogen deficient plants
resulting in short, spindly plants. The yellowing in nitrogen deficiency is uniform over the entire
leaf including the veins. In some plants the underside of the leaves and/or the petioles and midribs
develop traces of a reddish or purple color. In some plants this coloration can be quite bright. As
the deficiency progresses, the older leaves also show more of a tendency to wilt under mild water
stress and become senescent much earlier than usual. Recovery of plants suffering from this
deficiency, following the application of nitrogen, is immediate (days) and spectacular.
Phosphorus -deficient leaves show some necrotic spots. As a rule, symptoms of phosphorus
deficiency are not very distinct and thus difficult to identify. A major visual symptom is that the plants
are dwarfed or stunted. Phosphorus deficient plants develop very slowly in relation to other plants
growing under similar environmental conditions but without phosphorus deficiency. Phosphorus
deficient plants are often mistaken for unstressed but much younger plants. Species such as
tomatoes, develop a distinct purpling of the stem, petiole and the under sides of the leaves. Under
severe deficiency conditions there is also a tendency for leaves to develop a blue-gray luster.
In older leaves with very severe deficiency conditions a brown netted veining of the leaves may
develop.
This leaf shows a general overall chlorosis, while retaining some green color. The veins and petioles
show a very distinct reddish color. The visual symptoms of sulfur deficiency are very similar to the
chlorosis characteristic of nitrogen deficiency. However, in sulfur deficiency the yellowing is much
more uniform over the entire plant including young leaves. A reddish color is often found on the
underside of the leaves and the petioles has a more pinkish tone and is much less vivid then is
characteristic of nitrogen deficiency. In cases of advanced sulfur deficiency, brown lesions and/
or necrotic spots often develop along the petiole, and the leaves tend to become more erect and
often twisted and brittle.
* See notice on Page 1
11
Appendix
Deficiencies in Tomatoes Crops
Deficiency
Zinc
Calcium
Boron
Symptoms
This leaf shows an advanced case of interveinal necrosis. In the early stages of zinc deficiency the
younger leaves become yellow and pitting develops in the interveinal upper surfaces of the mature
leaves. Guttation is also prevalent. As the deficiency progresses, these symptoms develop into
an intense interveinal necrosis but the main veins remain green, as in the symptoms of recovering
iron deficiency. In many plants, especially trees, the leaves become very small and the internodes
shorten, producing a rosette like appearance.
Calcium-deficient leaves show necrosis around the base of the leaves. The very low mobility of
calcium is a major factor determining the expression of calcium deficiency symptoms in plants.
Classic symptoms of calcium deficiency include blossom-end rot of tomato, which is generally
related to poor translocation of calcium to the tissue rather than a low external supply of calcium.
Very slow growing plants with a deficient supply of calcium may re-translocate sufficient calcium
from older leaves to maintain growth with only a marginal chlorosis of the leaves. Plants suffering
from chronic calcium deficiency have a much greater tendency to wilt than non- stressed plants.
Boron-deficient plants show a light general chlorosis. The tolerance of plants to boron varies
greatly, to the extent that the boron concentrations necessary for the growth of plants having a
high boron requirement may be toxic to plants sensitive to boron. Boron is transported poorly in
the phloem of most plants.
Chloride
These leaves have abnormal shapes, with distinct interveinal chlorosis. Plants require relatively
high chlorine concentration in their tissues. Chlorine is very abundant in soils, and reaches high
concentrations in saline areas. The most common symptoms of chlorine deficiency are chlorosis
and wilting of the young leaves.
Copper
Copper-deficient leaves are curled, and their petioles bend downward. Copper deficiency may be
expressed as a light overall chlorosis along with the permanent loss of turgor in the young leaves.
Recently matured leaves show netted, green veining with areas bleaching to a whitish gray. Some
leaves develop sunken necrotic spots and have a tendency to bend downward. Trees suffering
from chronic copper deficiency develop a rosette form of growth. Leaves are small and chlorotic
with spotty necrosis.
Iron
Potassium
Iron-deficient leaves show strong chlorosis at the base of the leaves with some green netting. The
most common symptom of iron deficiency starts out as an interveinal chlorosis of the youngest
leaves, evolves into an overall chlorosis, and ends as a totally bleached leaf. The bleached areas
often develop necrotic spots. Up until the time the leaves become almost completely white they
will recover upon application of iron. In the recovery phase the veins are the first to recover as
indicated by their bright green color. This distinct venial re-greening observed during iron recovery
is probably the most recognizable symptom in all of classical plant nutrition. Because iron has a low
mobility, iron deficiency symptoms appear first on the youngest leaves. Iron deficiency is strongly
associated with calcareous soils and anaerobic conditions,
Some of these leaves show marginal necrosis (tip burn), others at a more advanced deficiency
status show necrosis in the interveinal spaces between the main veins along with interveinal
chlorosis. This group of symptoms is very characteristic of K deficiency symptoms. Potassium
deficiency is generally characterized by a marginal chlorosis progressing into a dry leathery tan
scorch on recently matured leaves, even if potassium is given to the plants. Because potassium
is very mobile within the plant, symptoms only develop on young leaves in the case of extreme
deficiency. Potassium deficiency can be greatly alleviated in the presence of sodium but the
resulting sodium-rich plants are much more succulent than a high potassium plant.
* See notice on Page 1
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