Vegetable Pests and Diseases – The Gardening Register

Growing vegetables is never trouble free but if know what is wrong you have a better chance of eradicating it and, hopefully, save your affected vegetables.

This is a comprehensive article giving lots of detail on how to deal with most garden pests and diseases which affect vegetables.

Most vegetables are covered but if you need specific information about a particular crop drop me a line and I’ll add it to the article.

You can read the whole article by scrolling down or just click on the vegetable you are having trouble with:

Asparagus	Aubergine	Beans	Beetroot
Broccoli	Brussels Sprouts	Cabbage	Carrots
Garlic	Globe Artichoke	Jerusalem Artichoke	Leeks
Onions	Parsnips	Peas	Sweet Peppers
Potatoes	Radish	Rhubarb	Spinach
Swede	Sweetcorn	Tomatoes (Indoor)	Tomatoes (Outdoors)
Turnip

Asparagus
Trouble	Symptoms	Treatment	Prevention
Asparagus Beetle	Stems and leaves are eaten.	Spray with liquid Derris	None
Frost	Crop turns black and dies	None	Cover the crop with fleece if frost is expected
Rust	Reddish-brown sports appear on leaves during the summer.	Remove and burn affected shoots as soon as spots appear	None
Slugs	Spears are eaten.	Sprinkle area with slug pellets or add nematodes to your soil	Keep area clear of rubbish
Spindly Spears	Thin shoots produced instead of the usual thick spears.	None	Usually caused by cutting too long into the season. Don’t harvest after mid June.
Violet Root Rot	Roots covered with purple mould, leaves turn yellow and die.	If bad start again in a new site and don’t grow root crops in the same area. If possible isolate healthy plants.	None
Wind Rock	In exposed sites roots are loosened which can lead to rotting.	None	Provide support to stems or build windbreaks around the site

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Aubergine
Trouble	Symptoms	Treatment	Prevention
Aphid	Attack developing flower-heads.	Spray as soon as attacks appear.	None
Red Spider Mite	Mottling on upper surface of leaves with tiny mites on the underside.	Spray with liquid Derris and mist leaves regularly with water	None
Whitefly	Will weaken plants.	Spray every week or two until clear	None

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Beans
Trouble	Symptoms	Treatment	Prevention
Anthracnose	Brown sunken spots on pods.	Destroy affect plants and spray remaining plants	Rotate crops
Bean Seed Fly	A soil living grub which attack seeds which then fail to germinate or produce distorted seedlings. Mainly affects early crops.	Destroy damaged seedlings	Ensure the seed bed is properly prepared and dust the drills with Chlorophos
Black Bean Aphid	Stunted growth, damaged flowers and distorted pods.	Spray at the first sign of attack and repeat if necessary	Pinch out the tops of broad beans once four trusses of pods have formed
Birds	Seeds and seedlings eaten and damage to pods and flowers	None	Place netting over crops
Botrytis (Grey Mould)	Grey velvety mould on pods.	Burn affected pods and spray remaining crop.	Spray at flowering time if this is a known problem
Chocolate Spot	Small brown spots on leaves and dark streaks along stems.	Lift and destroy diseased plants and spray remaining plants	Apply fertiliser prior to sowing and don’t sow too close together
Downy Mildew	Yellow blotches on leaves with brown mould underneath. Pods are spotted and distorted.	Spray at the first sign of disease and repeat every fortnight if necessary.	Burn affected plants after picking. Rotate crops
Foot and Root Rot	Leaves turn yellow and shrivel. Roots and the base of stems turn black and rot.	Burn affected plants and water the soil with Cheshunt Compound to avoid spreading the disease	Rotate crops
Flowers (none)	Flowers not produced.	Can be caused by disease but most likely is caused by too much nitrogen in the soil	Always use a fertiliser with phosphates and potash
Fusarium Wilt	Stunted growth. Yellowing or rolled leaves. Little crop.	Burn affected plants.	Grow wilt resistant varieties
Grey Mould (Botrytis)	Grey velvety mould on pods.	Burn affected pods and spray remaining crop.	Spray at flowering time if this is a known problem
Halo Blight	Small brown spots surrounded by a yellow “halo” on the leaves. Stunted plants.	Lift and destroy diseased plants	Never soak seed and rotate crops
Leaf and Pod Spot	Brown sunken spots on pods. Discoloured peas.	Destroy affect plants and spray remaining plants	Rotate crops
Marsh Spot	Brown-lined cavity in the centre of peas caused by shortage of manganese.	None	Add compost prior to sowing and apply a sequestered compound
Mice	Will eat seeds and seedlings.	None	Dip seed in paraffin or alum, place spiny branches along the rows or use a normal mouse trap.
Pea Aphid	Stunted growth and damaged flowers.	Spray at the first sign of attack and repeat if necessary	None
Pea and Bean Weevil	U-shaped notches at the edges of leaves. Seedlings can be killed but older plants tend to recover.	Spray at the first sign of attack	Hoe around plants during April and May to prevent further attack
Pea Thrips	Silvery patches on leaves and pods. Pods distorted.	Spray at the first sign of attack	Remove infected plants and dig over the soil before replanting
Pea Moth	Pea moth maggots burrow through pods into seeds.	None	Spray just as the flowers appear
Pods (none)	No pods develop	The loss of flowers without producing pods is often caused by birds or bees but can also be caused by roots drying out	Keep roots moist and mulch
Powdery Mildew	White powdery patches on both sides of leaves. Pods are covered in white patches.	Spray at the first sign of disease and repeat every fortnight if necessary	Burn affected plants after picking
Seed Beetle	Small round holes appear which house the seed beetle grub. Seeds don’t germinate or produce bad seedlings.	None	Buy good quality seeds and don’t plant any which show signs of holes

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Beetroot
Trouble	Symptoms	Treatment	Prevention
Black Leg	Seedlings turn black and shrivel	Remove diseased plants and water remainder with Cheshunt Compound	Sow thinly in well drained soil
Bolting	Run to seed before roots develop	None	Grow resistant varieties, don’t allow to dry out and thin seedlings as soon as possible
Fanging	Forked Roots	None	Do not add fresh manure to the soil to close to sowing and ensure the soil is stone free and well prepared
Heart Rot	Leaves wilt and brown, sunken patches on the tops of roots.	Spray repeatedly	If soil is Boron deficient add borax
Leaf Spot	Brown spots on leaves. Leaves disfigures but does not affect the crop.	None	Rotate crops
Mangold Fly (Leaf Miner)	Small white grubs burrow into leaves causing blisters.	Destroy affected leaves and spray	None
Speckled Yellows	Yellow patches between veins of leaves. Leaf edges roll inwards.	Caused by manganese deficiency so apply sequestered compound	Do not over lime the soil

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Broccoli
Trouble	Symptoms	Treatment	Prevention
Boron Deficiency	Young leaves are distorted. Brown patches on the curds.	Spray at first signs of deficiency	Apply borax before planting
Black Rot	Yellowing leaves with black veins. Will kill seedlings and mature plants are stunted.	None	Rotate crops
Cutworm	Large grey or brown caterpillars attack young plants at night and stems are severed below ground. Leaves and roots may also be eaten.	Hoe the soil around the plant during June and July and destroy caterpillars as they are found	Rake Chlorophos into the soil prior to planting
Chafer Grubs	Wilting leaves. Fat, curved grubs may be seen in the soil. The plants will die.	None	Destroy grubs as they are found during autumn digging and rake Chlorophos into the soil prior to planting
Club Root	Discoloured leaves wilt in the sun. Plants will die or grow slowly.	None	Lime well and ensure the soil is well drained. Dip transplant roots in thiophanate-methyl before planting. Rotate crops
Cabbage Caterpillars	Holes in leaves.	Spray as soon as attack appears	If white butterflies are found around the plants inspect the leaves and remove any eggs
Diamond-Back Moth	Green caterpillars fed on the underside of leaves.	Spray at first sign of attack	None
Downy Mildew	Yellowing of upper surface with white furry fungus growth beneath.	Spray at first stage of disease	Sow seeds in sterilised compost. Do not over-crowd and don’t raise seedlings where the disease has been before.
Flea Beetle	Lots of small, round holes in leaves. Seedlings can be killed.	Spray at the first sign of attack. Water plants well in dry weather.	Treating seeds with an insecticidal seed dressing will prevent early attacks
Frost	Can kill plants if it reaches the roots. Affected leaves are easily attacked by fungi or bacteria.	Burn damaged leaves	Ensure plants are firmed well when transplanting
Gall Weevil	Swellings form close to ground level. Crops are rarely affected.	Not really needed.	Apply a soil-pest killer
Leaf Spot (Ring Spot)	Brown rings on mature leaves.	Burn diseased leaves and spray	Do not plant brassicas in the same spot next season
Mealy Aphid	Waxy, greyish “greenflies” appear underneath leaves. Leaves curl and turn yellow.	Spray at the first sign of attack	Burn affected plants
Magnesium Deficiency	Yellowing between the veins of older leaves.	Apply a tonic around the plant and a fertiliser containing magnesium	Incorporate compost into the soil during Autumn digging
Manganese Deficiency	Similar in look to magnesium deficiency but tends to start on young leaves.	Apply a tonic around the plant	Incorporate compost into the soil during Autumn digging
Pigeons	Soft portion of leaves are eaten.	None	Netting is the only viable form of prevention
Slugs and Snails	Leaves and stems eaten. Young plants particularly at risk.	Use slug pellets or add nematodes to the soil	Keep the site clear of rubbish
Swede Midge	Leaf stalks near the growing point are swollen and distorted. Plant becomes blind.	Burn affected plants and spray those remaining	None
White Blister (White Rust)	White spots on leaves. Growth stunted and plants might die.	Burn diseased leaves and thin out plants to avoid over-crowding	Do not grow brassicas the following year
Wire Stem	Base of stems is black. Seedlings die.	None	Avoid growing seedlings in cold and wet soil. Avoid over-crowding
Whiptail	Thin, strap like leaves. Small cauliflower heads. Molybdenum deficiency.	Spray repeatedly	Ensure soil is adequately limed

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Brussels Sprouts
Trouble	Symptoms	Treatment	Prevention
Boron Deficiency	Young leaves are distorted and heads of cauliflowers are small and bitter. Brown patches on the curds.	Spray at first signs of deficiency	Apply borax before planting
Blown Brussels Sprouts	Open, leafy sprouts instead of tight button ones.	Remove blown sprouts	Ensure plenty of organic matter is added to the soil prior to planting and that the ground is well compacted. Ensure site is sunny and well watered.
Black Rot	Yellowing leaves with black veins. Will kill seedlings and mature plants are stunted.	None	Rotate crops
Cutworm	Large grey or brown caterpillars attack young plants at night and stems are severed below ground. Leaves and roots may also be eaten.	Hoe the soil around the plant during June and July and destroy caterpillars as they are found	Rake Chlorophos into the soil prior to planting
Chafer Grubs	Wilting leaves. Fat, curved grubs may be seen in the soil. The plants will die.	None	Destroy grubs as they are found during autumn digging and rake Chlorophos into the soil prior to planting
Club Root	Discoloured leaves wilt in the sun. Plants will die or grow slowly.	None	Lime well and ensure the soil is well drained. Dip transplant roots in thiophanate-methyl before planting. Rotate crops
Diamond-Back Moth	Green caterpillars fed on the underside of leaves.	Spray at first sign of attack	None
Downy Mildew	Yellowing of upper surface with white furry fungus growth beneath.	Spray at first stage of disease	Sow seeds in sterilised compost. Do not over-crowd and don’t raise seedlings where the disease has been before.
Flea Beetle	Lots of small, round holes in leaves. Seedlings can be killed.	Spray at the first sign of attack. Water plants well in dry weather.	Treating seeds with an insecticidal seed dressing will prevent early attacks
Frost	Can kill plants if it reaches the roots. Affected leaves are easily attacked by fungi or bacteria.	Burn damaged leaves	Ensure plants are firmed well when transplanting
Gall Weevil	Swellings form close to ground level. Crops are rarely affected.	Not really needed.	Apply a soil-pest killer
Leaf Spot (Ring Spot)	Brown rings on mature leaves.	Burn diseased leaves and spray	Do not plant brassicas in the same spot next season
Mealy Aphid	Waxy, greyish “greenflies” appear underneath leaves. Leaves curl and turn yellow.	Spray at the first sign of attack	Burn affected plants
Magnesium Deficiency	Yellowing between the veins of older leaves.	Apply a tonic around the plant and a fertiliser containing magnesium	Incorporate compost into the soil during Autumn digging
Manganese Deficiency	Similar in look to magnesium deficiency but tends to start on young leaves.	Apply a tonic around the plant	Incorporate compost into the soil during Autumn digging
Pigeons	Soft portion of leaves are eaten.	None	Netting is the only viable form of prevention
Slugs and Snails	Leaves and stems eaten. Young plants particularly at risk.	Use slug pellets or add nematodes to the soil	Keep the site clear of rubbish
White Blister (White Rust)	White spots on leaves. Growth stunted and plants might die.	Burn diseased leaves and thin out plants to avoid over-crowding	Do not grow brassicas the following year
Wire Stem	Base of stems is black. Seedlings die.	None	Avoid growing seedlings in cold and wet soil. Avoid over-crowding
Whiptail	Thin, strap like leaves. Molybdenum deficiency.	Spray repeatedly	Ensure soil is adequately limed

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Cabbage
Trouble	Symptoms	Treatment	Prevention
Boron Deficiency	Young leaves are distorted and heads of cauliflowers are small and bitter. Brown patches on the curds.	Spray at first signs of deficiency	Apply borax before planting
Black Rot	Yellowing leaves with black veins. Will kill seedlings and mature plants are stunted.	None	Rotate crops
Cabbage Stem Flea Beetle	Plants wilt and die. Small, cream grubs can be seen within the stems of cabbages.	None	Rotate crops
Cutworm	Large grey or brown caterpillars attack young plants at night and stems are severed below ground. Leaves and roots may also be eaten.	Hoe the soil around the plant during June and July and destroy caterpillars as they are found	Rake Chlorophos into the soil prior to planting
Chafer Grubs	Wilting leaves. Fat, curved grubs may be seen in the soil. The plants will die.	None	Destroy grubs as they are found during autumn digging and rake Chlorophos into the soil prior to planting
Cabbage Whitefly	Tiny white moths and larvea feed on underside of leaves. Sooty moulds develop and plants are weakened.	Spray at the first sign of attack and repeat as needed	None
Cabbage Root Fly	Blue-tinged leaves which wilt in the sun. Cabbages fail to heart and cauliflowers form small heads	Spray around the base of plants	Sprinkle Chlorophos around the base after transplanting
Club Root	Discoloured leaves wilt in the sun. Plants will die or grow slowly.	None	Lime well and ensure the soil is well drained. Dip transplant roots in thiophanate-methyl before planting. Rotate crops
Cabbage Caterpillars	Holes in leaves.	Spray as soon as attack appears	If white butterflies are found around the plants inspect the leaves and remove any eggs
Diamond-Back Moth	Green caterpillars fed on the underside of leaves	Spray at first sign of attack	None
Downy Mildew	Yellowing of upper surface with white furry fungus growth beneath	Spray at first stage of disease	Sow seeds in sterilised compost. Do not over-crowd and don’t raise seedlings where the disease has been before.
Flea Beetle	Lots of small, round holes in leaves. Seedlings can be killed.	Spray at the first sign of attack. Water plants well in dry weather.	Treating seeds with an insecticidal seed dressing will prevent early attacks
Frost	Can kill plants if it reaches the roots. Affected leaves are easily attacked by fungi or bacteria.	Burn damaged leaves	Ensure plants are firmed well when transplanting
Gall Weevil	Swellings form close to ground level. Crops are rarely affected.	Not really needed.	Apply a soil-pest killer
Heartless Cabbages	No heart in the cabbages	None	Ensure plenty of organic matter is added to the soil prior to planting and that the ground is well compacted. Ensure site is sunny and well watered.
Leaf Spot (Ring Spot)	Brown rings on mature leaves.	Burn diseased leaves and spray	Do not plant brassicas in the same spot next season
Mealy Aphid	Waxy, greyish “greenflies” appear underneath leaves. Leaves curl and turn yellow.	Spray at the first sign of attack	Burn affected plants
Magnesium Deficiency	Yellowing between the veins of older leaves	Apply a tonic around the plant and a fertiliser containing magnesium	Incorporate compost into the soil during Autumn digging
Manganese Deficiency	Similar in look to magnesium deficiency but tends to start on young leaves	Apply a tonic around the plant	Incorporate compost into the soil during Autumn digging
Pigeons	Soft portion of leaves are eaten	None	Netting is the only viable form of prevention
Slugs and Snails	Leaves and stems eaten. Young plants particularly at risk.	Use slug pellets or add nematodes to the soil	Keep the site clear of rubbish
Split Hearts	Cabbage heads split	None	Water regularly during dry weather and protect from frost
Swede Midge	Leaf stalks near the growing point are swollen and distorted. Plant becomes blind.	Burn affected plants and spray those remaining	None
White Blister (White Rust)	White spots on leaves. Growth stunted and plants might die.	Burn diseased leaves and thin out plants to avoid over-crowding	Do not grow brassicas the following year
Wire Stem	Base of stems is black. Seedlings die.	None	Avoid growing seedlings in cold and wet soil. Avoid over-crowding
Whiptail	Thin, strap like leaves. Small cauliflower heads. Molybdenum deficiency.	Spray repeatedly	Ensure soil is adequately limed

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Carrot
Trouble	Symptoms	Treatment	Prevention
Black Rot	Blackened Carrot Roots seen on stored carrots	Burn diseased roots	Store properly and do not use the same land for carrots next year
Carrot Fly	Reddish leaves which wilt in the sun. Seedlings die and mature roots are riddled with holes and will rot	None	Don’t grow near tall plants, sow thinly and destroy all thinnings
Clayburn	Not serious but will produce blackened roots	None	Dig out any clay in the soil before sowing
Carrot-Willow Aphid	Distorted, discoloured and stunted leaves and weak plants. Transmits Motley Dwarf Virus.	Spray at first sign of attack	None
Fanging	Forked roots	None	Don’t add manure or compost prior to sowing. Don’t make beds too firm
Green Top	Tops of carrots are green caused by exposure to the sun	None	Earth up around the carrots
Motley Dwarf Virus	Discoloured leaves, reduced growth and yield. Spread by Carrot-Willow Aphid.	None	Spray young carrots
Small Roots	Small carrots	None	Dig soil deeply and break up any clay by adding well-rotted manure or compost
Sclerotinia Rot	Mouldy Roots found on stored carrots	None	Ensure roots are firm and disease free before storing
Splitting	Split roots caused by heavy rain. These carrots will not store successfully	None but can still be eaten	Water regularly in dry weather and apply a mulch to conserve moisture
Swift Moth	Hollowed-out roots caused by caterpillars	None	Use Chlorophos to control
Violet Root Rot	Mouldy roots and yellowing leaves	None	Rotate crops

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Garlic
Trouble	Symptoms	Treatment	Prevention
Rust	Orange spots and blotches on surface of leaves.	None. Lift and burn affected plants	Don’t grow garlic on affected ground for three years.
White Rot (Mouldy Nose)	Foliage turns yellow and wilts. Fluffy white mould on base of bulbs and round black bodies appear in the fungus.	None. Lift and burn affected plants.	Don’t grow garlic or others from the onion family on affected ground for three years.
Top Sets	Garlic cloves form on the stalk.	Gather and use the top sets in the usual way.	This is due to changeable weather in spring so there isn’t anything to be done.

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Globe Artichoke
Trouble	Symptoms	Treatment	Prevention
Aphid	Attack developing flower-heads	Spray as soon as attacks appear	None
Petal Blight	Brown spots join together to ruin young heads	Remove and burn the affected heads	Spray as flower buds appear
Slugs	Young shoots are eaten	Sprinkle area with slug pellets or add nematodes to your soil	Keep area free of all rubbish

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Jerusalem Artichoke
Trouble	Symptoms	Treatment	Prevention
Sclerotinia Rot	Base of stems are attacked, appears as fluffy white mould	Lift and burn diseased plants. Water healthy plants with Cheshunt Compound	None
Slugs	Tubers are hollowed-out	Sprinkle area with slug pellets or add nematodes to your soil	Keep area clear of all rubbish

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Leek
Trouble	Symptoms	Treatment	Prevention
Onion Fly	Yellow, drooping leaves. Maggots burrow into the bases and kill young plants.	None. Lift and burn affected plants.	Rake Chlorophos into soil before showing or planting. Sets are less prone than seeds.
Bolting	Premature production of flower-heads.	Cut off flower stalks and lift as usual. Do not store.	Don’t sow or plant too early in the season. Ensure soil is firmed well before sowing or planting
Stem & Bulb Eelworm	Swollen, distorted foliage. Young plants die and older plants product soft bulbs.	None. Lift and burn affected plants.	Do not grow onions, peas, beans or strawberries on land previous infected with this disease.
Saddleback	On harvesting, bulbs are split at the base. Caused by heavy rain or watering after a dry period.	None. Use affected bulbs immediately.	Keep well watered during dry spells.
Set Division	Onions from sets produce twin bulbs.	None	Plant sets in good soil and keep well watered in dry spells.
Smut	Black spots and blotches on leaves and bulbs of young plants. Twisted and thickened leaves. More likely in leeks than onions.	None. Lift and burn affected plants.	Don’t grow leeks or onions on affected ground for eight years.
Rust	Orange spots and blotches on surface of leaves. More likely in leeks than onions.	Remove and burn affected leaves.	Don’t grow leeks or onions on affected ground for one season.
White Tip	Tips of leek leaves turn white and papery in autumn.	Spray with Dithane at first signs. Lift and burn badly affected plants.	Don’t grow leeks or onions on affected ground for one season.
Bull Neck (Thick Neck)	Abnormally thick necks means the bulbs will not store successfully.	None	Don’t use too much manure. Use a feed with more potash than nitrogen. Don’t sow seed too deeply.
Downy Mildew	Downy, grey mould covering leaves. Leave die back slowly and shrivel. Bulbs are soft and don’t store well.	Spray with Dithane at first signs. Repeat fortnightly.	Grow onions on a difference site each year and ensure soil is well drained.
Leek Moth	Tunnelled leaves. Caterpillars feed inside young leaves leaving the outer skin. Also attacks leeks.	Spray with a contact insecticide at first signs of attack. Destroy badly affected leaves.	None
White Rot (Mouldy Nose)	Foliage turns yellow and wilts. Fluffy white mould on base of bulbs and round black bodies appear in the fungus.	None. Lift and burn affected plants.	None. Don’t grow onions on affected land for eight years.
Shanking	The centre leaves turn yellow and collapse, outer leaves follow later. Evil-smelling slime within scales.	None. Lift and burn affected plants.	None. Don’t grow onions on affected land for several years.
Neck Rot	During storage a grey mould appears near the neck. Bulbs are soft and rotten.	None. Remove rotten bulbs.	Dist seeds and sets with benomyl before planting. Dry bulbs thoroughly before storing. Don’t store soft bulbs or bulbs with green necks.

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Onions
Trouble	Symptoms	Treatment	Prevention
Onion Fly	Yellow, drooping leaves. Maggots burrow into the bases and kill young plants.	None. Lift and burn affected plants.	Rake Chlorophos into soil before showing or planting. Sets are less prone than seeds.
Bolting	Premature production of flower-heads.	Cut off flower stalks and lift as usual. Do not store.	Don’t sow or plant too early in the season. Ensure soil is firmed well before sowing or planting
Stem & Bulb Eelworm	Swollen, distorted foliage. Young plants die and older plants product soft bulbs.	None. Lift and burn affected plants.	Do not grow onions, peas, beans or strawberries on land previous infected with this disease.
Saddleback	On harvesting, bulbs are split at the base. Caused by heavy rain or watering after a dry period.	None. Use affected bulbs immediately.	Keep well watered during dry spells.
Set Division	Onions from sets produce twin bulbs.	None	Plant sets in good soil and keep well watered in dry spells.
Smut	Black spots and blotches on leaves and bulbs of young plants. Twisted and thickened leaves. More likely in leeks than onions.	None. Lift and burn affected plants.	Don’t grow leeks or onions on affected ground for eight years.
Rust	Orange spots and blotches on surface of leaves. More likely in leeks than onions.	Remove and burn affected leaves.	Don’t grow leeks or onions on affected ground for one season.
White Tip	Tips of leek leaves turn white and papery in autumn.	Spray with Dithane at first signs. Lift and burn badly affected plants.	Don’t grow leeks or onions on affected ground for one season.
Bull Neck (Thick Neck)	Abnormally thick necks means the bulbs will not store successfully.	None	Don’t use too much manure. Use a feed with more potash than nitrogen. Don’t sow seed too deeply.
Downy Mildew	Downy, grey mould covering leaves. Leave die back slowly and shrivel. Bulbs are soft and don’t store well.	Spray with Dithane at first signs. Repeat fortnightly.	Grow onions on a difference site each year and ensure soil is well drained.
Leek Moth	Tunnelled leaves. Caterpillars feed inside young leaves leaving the outer skin. Also attacks leeks.	Spray with a contact insecticide at first signs of attack. Destroy badly affected leaves.	None
White Rot (Mouldy Nose)	Foliage turns yellow and wilts. Fluffy white mould on base of bulbs and round black bodies appear in the fungus.	None. Lift and burn affected plants.	None. Don’t grow onions on affected land for eight years.
Shanking	The centre leaves turn yellow and collapse, outer leaves follow later. Evil-smelling slime within scales.	None. Lift and burn affected plants.	None. Don’t grow onions on affected land for several years.
Neck Rot	During storage a grey mould appears near the neck. Bulbs are soft and rotten.	None. Remove rotten bulbs.	Dist seeds and sets with benomyl before planting. Dry bulbs thoroughly before storing. Don’t store soft bulbs or bulbs with green necks.

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Parsnips
Trouble	Symptoms	Treatment	Prevention
Black Rot	Blackened Carrot Roots seen on stored carrots	Burn diseased roots	Store properly and do not use the same land for carrots next year
Clayburn	Not serious but will produce blackened roots	None	Dig out any clay in the soil before sowing
Fanging	Forked roots	None	Don’t add manure or compost prior to sowing. Don’t make beds too firm
Parsnip Canker	Blackened Parsnip roots which crack leaving the root to rot	None	Lime the soil and don’t sow too early.
Small Roots	Small parsnips	None	Dig soil deeply and break up any clay by adding well-rotted manure or compost
Sclerotinia Rot	Mouldy Roots found on stored parsnips	None	Ensure roots are firm and disease free before storing
Splitting	Split roots caused by heavy rain. These parsnips will not store successfully	None but can still be eaten	Water regularly in dry weather and apply a mulch to conserve moisture
Swift Moth	Hollowed-out roots caused by caterpillars	None	Use Chlorophos to control
Violet Root Rot	Mouldy roots and yellowing leaves	None	Rotate crops

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Peas
Trouble	Symptoms	Treatment	Prevention
Anthracnose	Brown sunken spots on pods.	Destroy affect plants and spray remaining plants	Rotate crops
Bean Seed Fly	A soil living grub which attack seeds which then fail to germinate or produce distorted seedlings. Mainly affects early crops.	Destroy damaged seedlings	Ensure the seed bed is properly prepared and dust the drills with Chlorophos
Black Bean Aphid	Stunted growth, damaged flowers and distorted pods.	Spray at the first sign of attack and repeat if necessary	Pinch out the tops of broad beans once four trusses of pods have formed
Birds	Seeds and seedlings eaten and damage to pods and flowers	None	Place netting over crops
Botrytis (Grey Mould)	Grey velvety mould on pods.	Burn affected pods and spray remaining crop.	Spray at flowering time if this is a known problem
Chocolate Spot	Small brown spots on leaves and dark streaks along stems.	Lift and destroy diseased plants and spray remaining plants	Apply fertiliser prior to sowing and don’t sow too close together
Downy Mildew	Yellow blotches on leaves with brown mould underneath. Pods are spotted and distorted.	Spray at the first sign of disease and repeat every fortnight if necessary.	Burn affected plants after picking. Rotate crops
Foot and Root Rot	Leaves turn yellow and shrivel. Roots and the base of stems turn black and rot.	Burn affected plants and water the soil with Cheshunt Compound to avoid spreading the disease	Rotate crops
Flowers (none)	Flowers not produced.	Can be caused by disease but most likely is caused by too much nitrogen in the soil	Always use a fertiliser with phosphates and potash
Fusarium Wilt	Stunted growth. Yellowing or rolled leaves. Little crop.	Burn affected plants.	Grow wilt resistant varieties
Grey Mould (Botrytis)	Grey velvety mould on pods.	Burn affected pods and spray remaining crop.	Spray at flowering time if this is a known problem
Halo Blight	Small brown spots surrounded by a yellow “halo” on the leaves. Stunted plants.	Lift and destroy diseased plants	Never soak seed and rotate crops
Leaf and Pod Spot	Brown sunken spots on pods. Discoloured peas.	Destroy affect plants and spray remaining plants	Rotate crops
Marsh Spot	Brown-lined cavity in the centre of peas caused by shortage of manganese.	None	Add compost prior to sowing and apply a sequestered compound
Mice	Will eat seeds and seedlings.	None	Dip seed in paraffin or alum, place spiny branches along the rows or use a normal mouse trap.
Pea Aphid	Stunted growth and damaged flowers.	Spray at the first sign of attack and repeat if necessary	None
Pea and Bean Weevil	U-shaped notches at the edges of leaves. Seedlings can be killed but older plants tend to recover.	Spray at the first sign of attack	Hoe around plants during April and May to prevent further attack
Pea Thrips	Silvery patches on leaves and pods. Pods distorted.	Spray at the first sign of attack	Remove infected plants and dig over the soil before replanting
Pea Moth	Pea moth maggots burrow through pods into seeds.	None	Spray just as the flowers appear
Pods (none)	No pods develop	The loss of flowers without producing pods is often caused by birds or bees but can also be caused by roots drying out	Keep roots moist and mulch
Powdery Mildew	White powdery patches on both sides of leaves. Pods are covered in white patches.	Spray at the first sign of disease and repeat every fortnight if necessary	Burn affected plants after picking
Seed Beetle	Small round holes appear which house the seed beetle grub. Seeds don’t germinate or produce bad seedlings.	None	Buy good quality seeds and don’t plant any which show signs of holes

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Sweet Peppers
Trouble	Symptoms	Treatment	Prevention
Aphid	Attack developing flower-heads	Spray as soon as attacks appear	None
Red Spider Mite	Mottling on upper surface of leaves with tiny mites on the underside	Spray as soon as attacks appear and mist leaves regularly with water	None
Blossom End Rot	Brown patches at bottom of fruit	None	Water well throughout the season

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Potatoes
Trouble	Symptoms	Treatment	Prevention
Aphid	Plant infested with greenfly.	Spray at first sign of attack	None
Blackleg	Blackened stems at and below ground level. Leaves turn yellow and wilt.	None	Do not plant soft or rotten seed tubers and don’t cut tubers
Capsid Bug	Small brown spots in leaves, later turn into holes	Spray if attack is bad, will not affect yield	None
Common Scab	Ragged-edged scurfy patches. Only on the skin, the flesh is not affected.	None	Buy healthy seed tubers. Do not Lime.
Dry Rot	Shrunken area with white pustules during storage.	None	Rotate crops. Ensure tubers are sound before storing and handle carefully.
Frost	Black stems or yellow patches on leaves	None	Cover if frost is expected
Gapping	Seed potatoes do not develop shoots	None	Buy healthy seed tubers and ensure they are kept in a frost-free location
Gangrene	Dark brown depressions on the surface of the tuber	None	Store only sound tubers and keep air and frost-free
Hollow Heart	Hollow centre of tubers	None	Keep well watered during dry spells
Leaf Roll Virus	Leaves are rolled upwards and become hard and brittle	None	Buy healthy seed tubers. Spray to control the virus-carrying aphids.
Mosaic Virus	Yellow or pale green mottling over the surface of the leaf	None	Buy healthy seed tubers. Spray to control the virus-carrying aphids.
Magnesium Deficiency	Yellowing between the veins of the leaves which turns brown and brittle. Stunted growth.	Apply MultiTonic and spray with Fillip	Feed regularly during the growing season using a fertiliser with magnesium
Potato Blight	Brown patches on the leaves with white mould on the underside of each spot. Can destroy all the foliage. grey patches below the skin.	None	Buy healthy seed tubers. Spray with Dithane in July and repeat every fortnight if the weather is damp. Keep earthed up.
Potato Cyst Eelworm	Weak and stunted plants. Small tubers produced	None	Rotate crops. Don’t grow potatoes or tomatoes on infected land for at least six years
Powdery Scab	Round patches with raised margins on the skin.	None	Rotate crops
Rosy Rustic Moth	Hollow stems causing plants to die down early	None	None
Splitting	Deep cracks on surface of tubers	None	Do not store. Keep plants well watered during dry spells.
Slugs	Large holes in the tubers	None	Don’t add too much manure and lift tubers as soon as they mature. Keep the area free of rubbish.
Spraing	Curved lines in the flesh	None	Rotate crops
Soft Rot	Soft, evil-smelling flesh	None	Store only sound tubers and keep dry
Spindly Sprouts	Thin shoots	Stand tubers in a light cool place	Buy healthy seed tubers and ensure they are sprouted in a light, frost-free location.
Soft Tubers	Soft and rubbery tubers	None	Water well during drought conditions
Wireworm	Orange, shiny larvae produce tunnels in the flesh of tubers	None	Rake Chlorophos into the soil before planting and lift tubers as soon as they are mature.
Wart Disease	Black warty outgrowths on tubers	None	Only plant immune varieties on infected land

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Radish
Trouble	Symptoms	Treatment	Prevention
Brown Heart	Grey-brown rings through the flesh. Roots will be bitter. Caused by boron deficiency.	None	Apply borax before planting
Black Rot	Yellow leaves with black veins. Ring of black dots just below the skin.	None	Rotate crops and ensure the soil is well drained.
Soft Rot	Wet, slimy rot at the crown of both growing and stored crops. Can be serious.	None	Soil should be well drained and avoid adding too much manure at digging time. Rotate crops.

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Rhubarb
Trouble	Symptoms	Treatment	Prevention
Crown Rot	The terminal bud and the tissue below the crown rots.	None	Do not replant in the affected area
Honey Fungus	White streaks in the brown, dead tissue of the crown. Orange toadstools on the plants.	None	None

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Spinach
Trouble	Symptoms	Treatment	Prevention
Bolting	Premature flowering	None	Prepare the soil well and add compost and fertiliser. Plant bolt-resistant varieties
Downy Mildew	Yellow patches above and grey mould below leaves. Patches turn brown.	Pick off diseased leaves and spray at first sign of attack	Rotate crops. Ensure the soil is well drained and avoid overcrowding.
Leaf Spot	Spotted leaves.	Pick off diseased leaves and spray at first sign of attack	Rotate crops. Apply fertiliser before sowing.
Manganese Deficiency	Yellow blotches between the veins/	Apply fertiliser with manganese and spray with Fillip	Do not over lime the soil
Spinach Blight	Young leaves roll in and have a puckered, yellow surface.	None	Keep an eye on weeds and spray to control greenfly which carry the virus.

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Swede
Trouble	Symptoms	Treatment	Prevention
Brown Heart	Grey-brown rings through the flesh. Roots will be bitter. Caused by boron deficiency.	None	Apply borax before planting
Black Rot	Yellow leaves with black veins. Ring of black dots just below the skin.	None	Rotate crops and ensure the soil is well drained.
Soft Rot	Wet, slimy rot at the crown of both growing and stored crops. Can be serious.	None	Soil should be well drained and avoid adding too much manure at digging time. Rotate crops.

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Sweetcorn
Trouble	Symptoms	Treatment	Prevention
Frit Fly	The maggots bore into the growing points. Growth is stunted and small cobs.	None	Use seed dressed with insecticide or dust seedlings
Smut	Small balls (galls) appear on the cobs and stalks in hot, dry weather.	Cut off and burn the galls as soon as they appear.	Burn plants after harvest. Do not grow sweetcorn on the same site for three years.

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Tomato (Indoor)
Trouble	Symptoms	Treatment	Prevention
Blossom End Rot	Leathery dark-coloured patch at bottom of fruit	None	Don’t allow soil or compost to dry out
Blossom Drop	Flowers wither and break off	None	Water regularly and mist the flowers in the morning
Blotchy Ripening	Parts of the fruit fail to ripen	None	Control the heat in greenhouses and feed and water regularly
Buckeye Rot	Brown concentric rings around a grey spot on unripe fruit	None	Tie up lower trusses to avoid splashing. Apply a mulch.
Dry Set	Fruitlets stop growing	None	Mist plants twice a day with water
Eelworm	Stunted growth. Discoloured and wilted leaves. Tiny white cysts on roots.	None	Don’t grow tomatoes or potatoes in infested soil for at least six years.
Foot Rot	Stem bases are brown. Tends to affect seedlings.	None	Use sterilised soil or compost to raise seedlings. Don’t over water.
Greenback	The area around the stalk remains green and hard	None	Provide shade to greenhouses to control the heat. Feed regularly.
Ghost Spot	Grey mould spores fall on fruit leaving ‘water spots’	None	Provide good ventilation. Control Grey Mould and do not splash fruit when watering
Greenhouse Whitefly	Tiny moths on underside of leaves. Leaves are pale and curled. Sticky fruit with black mould.	Spray at first sign of attack	None
Grey Mould	Grey mould appears on damaged stems and can spread	Cut out diseased area	Ensure adequate ventilation, avoid over crowding and remove decaying leaves and fruit.
Hormone Damage	Fern-like and twisted leaves. Twisted stems and stalks.	None	Ensure lawn weed killer does not come in contact with plants
Hollow Fruit	Hollow fruit	None	Avoid too much heat or cold. Water regularly. Ensure adequate potash in the soil.
Leaf Roll	Rolled leaves is not a bad sign in young leaves as long as they are dark green. In older leaves it may be due to side variations in day and night temperatures. Provided no pests are present then no action is required.
Magnesium Deficiency	Yellowing between veins of leaves. Starts on lower leaves and moves up.	Use a foliar spray containing magnesium	None
Potato Blight	Bark brown blotches on leaves. Brown, shrunken areas on fruit. May develop during storage.	None	Tomatoes grown under glass are not always infected but to prevent a likely attack or for outdoor tomatoes use a protective spray of mancozeb (Dithane) or copper (Murphy Traditional Copper or Vitax Bordeaux Mixture). Try to apply these before the symptoms are seen but if this isn’t possible use as soon as possible. They will not totally prevent infection, but often slow it sufficiently to save the crop.
Root Rot	Roots are brown and corky. Plants wilt in hot weather.	Mulch to encourage new roots	Use new soil or fresh compost
Sun Scald	Pale brown, papery-skinned depression on side of fruit facing greenhouse glass	None	Paint glass and damp down well. Do not mist plants at mid-day.
Split Fruit	Fruits split	None	Keep roots moist
Stem Rot	Stem bases are brown. Tends to affect mature plants.	None	Sterilise greenhouse and equipment
Tomato Leaf Mould	Purple brown mould patches on underside of leaves, yellow patches on upper side. Lower leaves attacked first.	Remove some of the lower leaves and spray at first sign of attack.	Ventilate greenhouse at night
Tomato Moth	Large, green or brown caterpillars tunnel into fruit and stems.	None	Spray when small caterpillars holes appear in leaves
Virus	Mottled and curled leaves. Dark vertical streaks on the stems. Stunted growth. Mottled and bronzed fruits.	None	Buy virus-free plants. Spray to control greenfly
Verticillium Wilt	Leaves wilt in hot weather. Lower leaves turn yellow. Brown streaks through the stem tissue	Mulch around stem to encourage new roots.	Don’t grow tomatoes in infected soil

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Tomatoes (Outdoors)
Trouble	Symptoms	Treatment	Prevention
Blossom End Rot	Leathery dark-coloured patch at bottom of fruit	None	Don’t allow soil or compost to dry out
Blossom Drop	Flowers wither and break off	None	Water regularly and mist the flowers in the morning
Blotchy Ripening	Parts of the fruit fail to ripen	None	Control the heat in greenhouses and feed and water regularly
Buckeye Rot	Brown concentric rings around a grey spot on unripe fruit	None	Tie up lower trusses to avoid splashing. Apply a mulch.
Dry Set	Fruitlets stop growing	None	Mist plants twice a day with water
Eelworm	Stunted growth. Discoloured and wilted leaves. Tiny white cysts on roots.	None	Don’t grow tomatoes or potatoes in infested soil for at least six years.
Foot Rot	Stem bases are brown. Tends to affect seedlings.	None	Use sterilised soil or compost to raise seedlings. Don’t over water.
Hormone Damage	Fern-like and twisted leaves. Twisted stems and stalks.	None	Ensure lawn weed killer does not come in contact with plants
Hollow Fruit	Hollow fruit	None	Avoid too much heat or cold. Water regularly. Ensure adequate potash in the soil.
Leaf Roll	Rolled leaves is not a bad sign in young leaves as long as they are dark green. In older leaves it may be due to side variations in day and night temperatures. Provided no pests are present then no action is required.
Magnesium Deficiency	Yellowing between veins of leaves. Starts on lower leaves and moves up.	Use a foliar spray containing magnesium	None
Potato Blight	Bark brown blotches on leaves. Brown, shrunken areas on fruit. May develop during storage.	None	Use a protective spray of mancozeb (Dithane) or copper (Murphy Traditional Copper or Vitax Bordeaux Mixture). They will not totally prevent infection, but often slow it sufficiently to save the crop.
Root Rot	Roots are brown and corky. Plants wilt in hot weather.	Mulch to encourage new roots	Use new soil or fresh compost
Split Fruit	Fruits split	None	Keep roots moist
Tomato Moth	Large, green or brown caterpillars tunnel into fruit and stems.	None	Spray when small caterpillars holes appear in leaves
Virus	Mottled and curled leaves. Dark vertical streaks on the stems. Stunted growth. Mottled and bronzed fruits.	None	Buy virus-free plants. Spray to control greenfly
Verticillium Wilt	Leaves wilt in hot weather. Lower leaves turn yellow. Brown streaks through the stem tissue	Mulch around stem to encourage new roots.	Don’t grow tomatoes in infected soil

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Turnip
Trouble	Symptoms	Treatment	Prevention
Brown Heart	Grey-brown rings through the flesh. Roots will be bitter. Caused by boron deficiency.	None	Apply borax before planting
Black Rot	Yellow leaves with black veins. Ring of black dots just below the skin.	None	Rotate crops and ensure the soil is well drained.
Soft Rot	Wet, slimy rot at the crown of both growing and stored crops. Can be serious.	None	Soil should be well drained and avoid adding too much manure at digging time. Rotate crops.
Turnip Mosaic Virus	Young leaves are twisted and mottled. Dark green, raised spots on the leaves. Young plants can die.	None	Spray to control the greenfly carrier