crop walkers’ guide protected edibles part ii · crop walkers’ guide hdc is a division of the...

Crop Walkers’ Guide

HDC is a division of the Agriculture and Horticulture Development Board

Protected Edibles Part II

2 © Agriculture and Horticulture Development Board 2014

Introduction – Nutrient Disorders 5

Nutrient Disorders of tomato ANitrogen (N) A.1Phosphorus (P) A.2Potassium (K) A.3Calcium (Ca) A.4Magnesium (Mg) A.5Iron (Fe) A.6Copper (Cu) A.7Manganese (Mn) A.8Manganese (Mn) toxicity A.9Zinc (Zn) A.10Zinc (Zn) toxicity A.11Boron (B) A.12Boron (B) toxicity A.13Molybdenum (Mo) A.14

Nutrient Disorders of cucumber BNitrogen (N) B.1Phosphorus (P) B.2Potassium (K) B.3Calcium (Ca) B.4Magnesium (Mg) B.5Iron (Fe) B.6Copper (Cu) B.7Manganese (Mn) B.8Manganese (Mn) toxicity B.9Zinc (Zn) B.10

Contents

© Agriculture and Horticulture Development Board 2014 3

Zinc (Zn) toxicity B.11Boron (B) B.12Boron (B) toxicity B.13Molybdenum (Mo) B.14

Nutrient Disorders of pepper CNitrogen (N) C.1Phosphorus (P) C.2Potassium (K) C.3Sulphur (S) C.4Calcium (Ca) C.5Magnesium (Mg) C.6Iron (Fe) C.7Manganese (Mn) C.8Manganese (Mn) toxicity C.9Copper (Cu) C.10Zinc (Zn) C.11Boron (B) C.12Molybdenum (Mo) C.13

Introduction – Physiological Disorders

Physiological Disorders of tomato DChimera D.1Calcium Leaf Scorch D.2Foliage – CO2 toxicity D.3Foliage – herbicide damage D.4Blossom End Rot D.5Fruit disorders D.6

4 © Agriculture and Horticulture Development Board 2014

Fruit – Gold Speckle D.7Cat Face D.8Stem – vigour D.9

Physiological Disorders of cucumber EChimera E.1Calcium Leaf Scorch E.2Burned Heads E.3Leaf scorch E.4Guttation E.5Fasciation E.6Snotty Ends E.7Cold Stripe E.8

Physiological Disorders of pepper FChimera F.1Fruit – Gold Speckle F.2Blossom End Rot F.3Excess vigour F.4

CreditsAcknowledgements iPhotographic credits iiDisclaimer and copyright iii

Contents

© Agriculture and Horticulture Development Board 2014 5

Title

Maintaining the correct balance of plant nutrients is essential to producing a healthy crop. Whether this supply of nutrients is from a well maintained soil or from solution culture through NFT or substrate, it is important for growers and managers to be able to identify nutritional problems at the earliest stages so that corrective action can be taken.

When sampling foliage for nutritional status you should remove the youngest fully expanded leaves from plants that you are concerned about – but also from healthy plants for comparison. The results can then be compared to the information given in this guide.

Analysis of tissue, soil or solution can give an absolute indication when things go wrong – early indication can be given by changes in growth or foliage colour. This Crop Walkers’ Guide aims to provide that early indication.

Horticultural Development Company

Introduction - Nutrient Disorders

Nutrient Disorders of tomato

A

© Agriculture and Horticulture Development Board 2014 A.1

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` Growth is restricted and leaves of deficient plants are reduced in size and are pale green/yellow compared to normal (right).

` Areas of purple pigmentation may also develop before premature death of lower leaves.

` Normal range: 3.5 to 5.0% N Deficiency: < 2.5% N

Nitrogen (N)

A.2 © Agriculture and Horticulture Development Board 2014

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` Growth is severely restricted and undersides of leaves become purple and may die prematurely.

` Purpling can also appear when plants are cold or when N deficient.

` Small necrotic areas develop interveinally on older leaves.

` Normal range: 0.35 to 0.75% P Deficiency: < 0.2% P

Phosphorus (P)


` Fruit ripens unevenly (blotchy ripening) but this symptom can also have other causes.

` Yellow margins develop on the expanding leaves and these areas scorch easily.

` This marginal yellowing can develop interveinally if the deficiency persists.

` Normal range: 3.5 to 6.3% K Deficiency: < 2.5% K Severe deficiency: <1.0% K

Potassium (K)


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` The margins of the youngest leaves become scorched and cupped.

` Fruit may develop Blossom End Rot – but this can also be caused by environmental problems.

` Normal range: 2 to 4% Ca Deficiency: < 1.0% Ca

Calcium (Ca)


` Interveinal yellowing develops on the middle and lower leaves and gradually progresses up the plant.

` The yellowing spreads across the leaf until only the main veins and leaf margin remain green.

` Normal range: 0.35 to 0.8% Mg Deficiency: < 0.3% Mg

Magnesium (Mg)


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` The youngest leaves are completely yellow, reduced in size and may become almost white if not rectified.

` Fe deficiency is frequently induced during periods of poor root growth or disease.

` Fe deficiency is difficult to diagnose by leaf analysis.

` Normal range: 80 to 200µg/g Deficiency: < 60µg/g

Iron (Fe)


` The youngest leaves become dark and wilt – this may develop after frequent wilting into scorch.

` The margins of older leaves curl upwards and pale spots develop, firstly near the leaf tips.

` Flower buds fail to develop.

` Symptoms are rare but may resemble salinity damage.


Copper (Cu)


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` The margin and interveinal parts of the leaf become pale green then yellow.

` The finest veinal network remains green.

` Mn deficiency can be induced during periods of poor root growth, rapid foliage growth or high pH in the growing media.


Manganese (Mn)


` Excess Mn produces reddish-black deposits in the veins of lower leaves.

` Yellowing develops around the veins and spreads interveinally leading to premature death of the leaf.

` In severe cases of Mn toxicity spots develop on the stem and petioles and calyx tip scorch also occurs.

` Normal range: 100 to 300µg/g Toxicity: > 1000µg/g

Manganese (Mn) toxicity


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` Leaflets become curled downwards and inwards.

` The main vein remains green but interveinal areas become yellow.

` Brown areas develop near the midrib and main veins and on the petioles.


Zinc (Zn)


` Growth is restricted and becomes spindly.

` Interveinal yellowing develops on the leaflets while the petioles and underside of the veins become purple.

` The smallest leaflets may remain partly unfolded.


Zinc (Zn) toxicity


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` Yellowing of the tips of terminal leaflets is usually the first symptom. This can be induced by heavy fruit load.

` The yellowing will gradually spread over the whole leaf.

` Purple-brown deposits form in the main vein and can be easily seen with transmitted light.

` When severe, corky areas can develop near the calyx of the fruit.


Boron (B)


` Small brown spots which later enlarge and coalesce develop along the leaf margin and the calyx tips become scorched.

` Lower leaves become yellow and die rapidly as the symptoms spread up the plant.


Boron (B) toxicity


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` Growth is slightly restricted and leaves become yellow-green.

` The older leaves develop a pale yellow margin which spreads interveinally.

` The margins may become almost white or very pale brown.

` Unlike other nutrients, molybdenum deficiency occurs at low pH rather than high pH.

` Normal range: > 0.4µg/g Deficiency: < 0.3µg/g

Molybdenum (Mo)

B

Nutrient Disorders of cucumber

B

© Agriculture and Horticulture Development Board 2014 B.1

` Growth is restricted and fewer fruit develop.

` The leaves of deficient plants (left) are reduced in size and are pale green/yellow compared to normal (right).

` Leaf analysis shows 2% N in deficient leaf and 5% N in normal leaf (leaf lamina only).


Nitrogen (N)

B.2 © Agriculture and Horticulture Development Board 2014

` New growth is restricted and random necrotic patches develop on maturing leaves.

` Leaf analysis example shows 0.2% P


Phosphorus (P)


` Growth may not be severely affected but yield may be greatly reduced.

` Yellow margins develop on the expanding leaves and spread interveinally.

` Fruit from potassium deficient plants tend to be poorly developed at the proximal (stem) end.

` Normal range: 3 to 5% K (laminae); 12 to 16% K (petioles) Deficiency: < 2% K (laminae); <10% K (petioles)

Potassium (K)


` The margins of the youngest leaves become scorched and cupped.

` Normal range: 2 to 10% Ca

Calcium (Ca)


` Interveinal yellowing develops on the middle and lower leaves and gradually progresses up the plant, may be confused with Beet Pseudo Yellows Virus.

` The yellowing spreads across the leaf until only the main veins remain green.


Magnesium (Mg)


` The youngest leaves are completely yellow and reduced in size and may become almost white if not rectified.

` Fe deficiency is frequently induced during periods of poor root growth (during rapid lateral development) or disease.

` Fe deficiency is difficult to diagnose by leaf analysis.

` Deficiency: < 80µg/g Severe deficiency: < 40µg/g

Iron (Fe)


` Leaf size is greatly reduced and older leaves develop interveinal yellowing while mature leaves produce yellowing around the minor veins producing a mottled appearance. The main veins, leaf margin and isolated interveinal areas remain green.

` Flowering is restricted and young fruit have small sunken brown areas over a pale skin.

` Normal range: 7 to 17μg/g Deficiency: < 4μg/g

Copper (Cu)


` The margin and interveinal parts of the leaf become pale green then yellow.

` The finest veinal network remains green.

` Mn deficiency can be induced during periods of poor root growth or high pH in the growing media.


Manganese (Mn)


` Excess manganese produces reddish-black deposits in the veins of lower leaves.

` Yellowing develops around the veins and spreads interveinally leading to premature death of the leaf.




` Growth can be severely restricted – leaves and internodes are reduced in the head.

` Petiole and tendril development is also restricted.

` Leaves become yellow/green almost grey except for the main veins which stay green.


Zinc (Zn)


` Interveinal areas become yellow/green.

` The entire veinal network becomes dark green eventually becoming blackened – this helps distinguish this disorder from Mn deficiency.


Zinc (Zn) toxicity


` Foliage becomes very brittle and leaf tips become yellow – this develops into a broad cream margin on older leaves.

` The growing point may die out if the deficiency is severe.

` Fruit marking similar to “Cold Stripe” may also develop.


Boron (B)


` A narrow yellow leaf margin develops and rapidly becomes scorched - on young leaves this may produce cupping.

` The growing point may become white and die if the toxicity is severe.


Boron (B) toxicity


` Growth is restricted and leaves become pale green.

` Small pale yellow or white areas develop near the leaf margin.

` Lower leaves may wilt and die prematurely.

` As Mo levels are very low normally – it is difficult to indicate deficiencies with leaf analysis.


Molybdenum (Mo)

CC

Nutrient Disorders of pepper

© Agriculture and Horticulture Development Board 2014 C.1

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` Growth is severely restricted and leaves are yellow/green.

` Lower leaves become yellow and die prematurely.


Nitrogen (N)

C.2 © Agriculture and Horticulture Development Board 2014

` Growth is severely restricted but in contrast to N deficiency the foliage remains green.

` Leaf margins tend to curl up and lower leaves die prematurely.


Phosphorus (P)


` Growth is restricted and small red/brown spots develop from the leaf tips.

` Interveinal and marginal yellowing may also develop on older leaves.

` Normal range: 3.0 to 6.0% K Deficiency: < 2.0% K

Potassium (K)


` This deficiency is rare.

` Can be confused with N deficiency.

` Leaves become pale yellow/green and new leaves may be narrow and pointed.

` Normal range: 0.13% S

` Deficiency: < 0.04% S

Sulphur (S)


` The margins of the youngest leaves become yellow.

` Fruit damage – Blossom End Rot appears but this may also be physiological.

` High conductivity (EC) in the root zone and excessive levels of ammonium both increase the risk of Blossom End Rot.

` Normal range: 1.5% to 3.5% Ca Deficiency: < 1.0% Ca

Calcium (Ca)


` Interveinal yellow/green chlorosis on mature leaves although vein margins may remain darker green.


Magnesium (Mg)


` The youngest leaves are yellow/white and the leaf tips remain green at first as yellowing spreads from the leaf base.

` Iron deficiency is difficult to diagnose by leaf analysis.


Iron (Fe)


` The youngest leaves are bright yellow/green and small dark brown interveinal areas develop beginning near the tip.

` In severe cases leaves will wither and drop.


Manganese (Mn)


` Excess Mn produces yellow/green areas on lower leaves – these gradually spread over the whole leaf which will die prematurely.




` Growth is restricted and leaf size is reduced.

` Leaf margins tend to curl upwards.


Copper (Cu)


` Dark green leaves develop small purple areas randomly scattered interveinally, these areas become brown as they enlarge.


Zinc (Zn)


` New leaves of young plants become distorted.

` The most common symptom is the yellowing of tips on mature leaves with red/brown deposits in the veins that are clearly visible when viewed with transmitted light.


Boron (B)


` Leaves of seedlings in acid media become yellow and growth is restricted.

` Not common in substrate cropping.

` As Mo levels are normally very low it is difficult to indicate deficiencies with leaf analysis.


Molybdenum (Mo)

© Agriculture and Horticulture Development Board 2014

Introduction – Physiological Disorders

Plants can react to their environment in many ways, occasionally producing abnormal growth. Such changes in growth can be used as a guide to alter the growing conditions to avoid further problems. In some cases, the disorders are caused by permanent changes to the genetic makeup of the plant tissue and that part of the plant or the whole plant will have to be removed.

The aim of this section of the Crop Walkers’ Guide is to provide some indication of the range of symptoms that may be found.

AD

Physiological Disorders of tomato

© Agriculture and Horticulture Development Board 2014 D.1

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` This is caused by a genetic change in the actual tissues that leave some areas with less green cells, producing a range of leaf and fruit symptoms.

` Remove affected leaves or plants.

Chimera (Silvering)

D.2 © Agriculture and Horticulture Development Board 2014

` Frequently caused by poor water movement in the plant rather than by actual deficiency of calcium. Improve ventilation and provide sufficient irrigation.

Calcium Leaf Scorch


` Excess CO2 results in leaf bleaching; this image shows damage caused by a malfunction in the control system resulting in CO2 levels being very high.

Foliage – CO2 toxicity


` Symptoms vary with type of herbicide. Damage from hormone weedkillers is quite common, because only low levels are needed to produce symptoms in tomato.

Foliage – herbicide damage


` Frequently caused by poor water movement in the plant rather than by actual deficiency of calcium.

` Improve ventilation and provide sufficient irrigation. High conductivity (EC) in the root zone and excessive levels of ammonium both increase the risk of Blossom End Rot.

Blossom End Rot (BER)


` Red/Greens, Ring Cracking, Chimera and “Extra Bits” – caused by environmental (1 & 2) or genetic issues (3 & 4)

Fruit disorders

1 2

3 4


` Caused by an in-balance of calcium in the fruit.

` Crystals of calcium oxalate puncture the cells near the surface of the fruit producing the light flecking.

Fruit – Gold Speckle


` A problem where the stylar (flower) end of the fruit is damaged at or soon after pollination.

` It is more often seen on larger fruiting cultivars with numerous locules (all the illustrations are of beefsteak types).

` Low temperatures and vigorous growth seem to play a part as the problem tends to be an issue with unheated crops.

Cat Face(Corky Stylar Scar)


` Some cultivars produce stem damage – bifurcation (splitting) and lesions below leaves, especially where there is excessive vigour from grafted plants during the establishment phase of the crop.

Stem – vigour

E

Physiological Disorders of cucumber

© Agriculture and Horticulture Development Board 2014 E.1

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` This is caused by a genetic change in the actual tissues that leave some areas with less green cells producing a range of leaf and fruit symptoms.


Chimera

E.2 © Agriculture and Horticulture Development Board 2014

` Frequently caused by poor water movement in the plant rather than by actual deficiency of calcium. Improve ventilation and provide sufficient irrigation.

Calcium Leaf Scorch


` Caused by poor water movement in the early stages of establishment – confusingly this can be caused by both high and low humidity.

Burned Heads

Healthy Tightening

Going Gone


` Caused by poor water movement in the plant especially when light levels increase rapidly from dull to very bright in the mornings.

Leaf scorch


` Too much water applied and too little to do with it – the plant can “eject” water through hydathodes on the leaf edges, clearly seen here.

Guttation


` The plant produces multiple stems fused together.

Fasciation


` Caused by excessive root pressure – this is an increasing problem with newer cultivars and is difficult to balance the need for enough water without having excess.

Snotty Ends


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` Normally caused when cold damp stem fruits are rapidly dried by bright sunlight – hence the name. It can also be caused by excessive root pressure.

Cold Stripe

F

Physiological Disorders of pepper

© Agriculture and Horticulture Development Board 2014 F.1

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` This is caused by a genetic change in the tissues that leave some areas with less green cells producing a range of leaf and fruit symptoms.


Chimera

F.2 © Agriculture and Horticulture Development Board 2014

` Caused by an inbalance of calcium in the fruit.

` Crystals of calcium oxalate puncture the cells near the surface of the fruit producing the light flecking.

Fruit – Gold Speckle

© Agriculture and Horticulture Development Board 2014 F.3

` Frequently caused by poor water movement in the plant rather than by actual deficiency of calcium.

` Improve ventilation and provide sufficient irrigation. High conductivity (EC) in the root zone and excessive levels of ammonium both increase the risk of Blossom End Rot.

Blossom End Rot (BER)

F.4 © Agriculture and Horticulture Development Board 2014

` This is not common but can be seen on some cultivars when excess vigour allows continued development of fruit tissue inside the maturing fruit.

Excess vigour

© Agriculture and Horticulture Development Board 2014 i

Title

The HDC is grateful to Derek Hargreaves for writing this Protected Edibles Crop Walkers Guide, Gerry Hayman for technically editing it and Becky Turner for overseeing its production.

Our thanks also go to the British Tomato Growers’ Association, the Cucumber Growers’ Association and the Pepper Technology Group for supporting the production of this publication – we very much hope that it proves a helpful aid to your businesses.

Acknowledgements

ii © Agriculture and Horticulture Development Board 2014

The HDC is very grateful to:

Sections A, B, C – Nutrient disorders

All images are taken from MAFF/AFRC (1987) – Diagnosis of Mineral Disorders Vol 3 Glasshouse Crops, TSO and copyright resides with that publication.

Sections D, E, F – Physiological disorders

All images are courtesy and copyright of Derek Hargreaves.

Photographic credits

© Agriculture and Horticulture Development Board 2014 iii

Disclaimer and copyright

While the Agriculture and Horticulture Development Board, operating through its HDC division, seeks to ensure that the information contained within this document is accurate at the time of printing, no warranty is given in respect thereof and, to the maximum extent permitted by law, the Agriculture and Horticulture Development Board accepts no liability for loss, damage or injury howsoever caused (including that caused by negligence) or suffered directly or indirectly in relation to information and opinions contained in or omitted from this document.

© Agriculture and Horticulture Development Board 2014. No part of this publication may be reproduced in any material form (including by photocopy or storage in any medium by electronic means) or any copy or adaptation stored, published or distributed (by physical, electronic or other means) without the prior permission in writing of the Agriculture and Horticulture Development Board, other than by reproduction in an unmodified form for the sole purpose of use as an information resource when the Agriculture and Horticulture Development Board or the HDC is clearly acknowledged as the source, or in accordance with the provisions of the Copyright, Designs and Patents Act 1988. All rights reserved.

HDC is a registered trademark of the Agriculture and Horticulture Development Board (AHDB).

All other trademarks, logos and brand names contained in this publication are the trademarks of their respective holders. No rights are granted without prior written permission of the relevant owners.

crop walkers’ guide protected edibles part ii · crop walkers’ guide hdc is a division of the...

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