TREE AND FLOWER DISEASES

ALMOND

LEAF CURL

Swollen and malformed reddish blisters on leaves. Spray before buds burst in January or February with lime sulphur. Half pint in 2 gal. water.

ANTIRRHINUM

DOWNY MILDEW

Furry grey mould on leaf under-surface. Destroy crippled plants, feed and spray with zineb.

ASTER (Michaelmas daisy)

WILT

Browning and withering of leaves from bottom of plant up. Take short cuttings in early spring and plant out on fresh site in April.

ASTER (China)

FOOT ROT

Often encouraged by wet conditions. Provide good drainage and water in with Cheshunt compound.

WILT

Very serious, attacks stem half-way up and prevents flowering. Also contaminates soil. Grow resistant varieties.

BEGONIA

BACTERIAL WILT

Brown spots on leaves and on stalks so that branches wilt and die. Cut off affected parts and spray with colloidal copper.

CAMELLIA

LEAF BLOTCH

Greyish blotches — in young rooted cuttings. Cut off affected parts and spray with captan.

VIRUS

Yellow spots and streaks but the disease is not important.

CARNATION

STEM ROT

Leaves turn yellow and wither. Destroy affected plants and use sterilized soil for the cuttings.

LEAF SPOTS

Spray with colloidal copper.

DAHLIA

LEAFY GALL

Cauliflower-like growth of leaves. Destroy affected plants.

DELPHINIUM

MILDEW

Spray with Karathane.

BLACK ROOT ROT

Due to wet soil and lack of humus for aeration of the roots.

VIRUS

Leaf mottling and stunted flowers. Destroy plants.

ELM

DUTCH ELM DISEASE

In July or August leaves on a branch turn yellow, wilt and turn brown but remain on the tree. The tree in time shows dead branches in its crown (stag-headed). Encourage vigorous growth.

EUONYMUS

MILDEW

Often serious in southern districts. Spray with Karathane.

FREESIA

VIRUS

Leaves show pronounced striping. Best to destroy heavily infected stock and plant new stock.

GARDENIA

CANKER

Cut off any affected branches and spray with colloidal copper.

GLADIOLUS

DRY ROT

Black lesions on corms. Dip in organo-mercurial dust before planting. Plant on a fresh site each season.

GLOXINIA

VIRUS

Spotted Wilt. Circular brown bands appear on leaves. Destroy plants.

GODETIA

GREY MOULD

Dust with TCNB dust.

HYDRANGEA

MILDEW

Spray with Karathane.

IRIS

INK

On bulbous irises, black inky patches on bulbs, which should be burnt.

SOFT ROT

On bearded iris soft rotting of rhizomes.

Remove dead parts. Use fungicidal dust.

VIRUS

Chiefly on bulbous iris — leaves show mottling and flowers show ‘breaking’. Burn affected plants.

LEAF SPOT

Not usually serious if beds are well cleared of old leaves etc., in spring.

JUNIPER

RUST

Swollen branches producing white horn-like fruiting bodies containing brown spores. Cut off and burn.

LABURNUM

SILVER LEAF

Cut out and burn affected parts.

LARCH

CANKER

Orange fungus bodies on the cankered areas. Cut out and burn affected parts.

LILAC

BLIGHT

Blackens young shoots and flowers causing them to wither and droop. Cut out affected shoots.

LILIES

BOTRYTIS

Spots and brown patches on leaves. Spray-early with Bordeaux mixture.

VIRUS

Mosaic is common. Destroy infected plants and keep down aphids.

MAPLE

TAR SPOT

Black spots on leaves — not usually serious. Burn old leaves.

MECONOPSIS

DOWNY MILDEW

Serious in seedlings. Spray with zineb. Provide good cultivation.

MICHAELMAS DAISY (see Aster)

OAK

MILDEW

Can be serious on young oaks. Spray with Karathane.

PRIMULA

VIRUS

Mottling on leaves. Very common on all kinds of primulas. Destroy affected plants.

RANUNCULUS

RUST

Cluster cups on leaves. Other host is cocksfoot grass. Destroy affected foliage and spray the plant with colloidal cop-per.

RHODODENDRON

RUST

Orange spots on underside of leaf — not very common. Alternate host is spruce. Spray with thiram.

ROSE

CHLOROSIS

Leaves become pale due to iron deficiency. Apply Sequestrene.

LEAF BLACK SPOT

Spray with captan. Pick off infected leaves.

CANKER

Remove brown cankered shoots by pruning.

SPRUCE

RUST

On needles. The alternate host is rhododendron. Do not, therefore, grow rhododendrons on a site that is near spruce plantations.

STOCK

FOOT ROT

Plant collapses. Too much water round roots. Destroy plants.

VIRUS

Flower ‘breaking’ and mottled leaves. Often spread from infected brassicas. Destroy infected plants.

SWEET WILLIAM

RUST

Sometimes serious enough to need spraying of young plants with colloidal copper in autumn.

TAGETES

FOOT ROT

Due to wet soil conditions.

TULIP

FIRE

Scorching of leaves and spotting on petals. Soil is contaminated. Treat soil with TCNB at planting. Choose good bulbs and spray with zineb or captan early in spring on young foliage.

VIRUS

‘Breaking’ in flowers — plants are not much affected.

VIOLA

STEM ROT

Pansy Sickness — do not plant deeply — have good, well-drained soil — sprinkle 4 per cent Calomel Dust in planting holes, and change the site each season.

VIRUS

Causes ‘breaking’ in flower petals. Affected plants should be destroyed.

VIOLET

SMUT

Swollen blisters on shoots, and leaves contain black powdery spores. Spray Bordeaux mixture after destroying affected plants.

WALLFLOWER

DOWNY MILDEW

Occasionally serious. Spray with zineb.

WINTER KILLING

Frost injury common on soft-grown plants.

VIRUS

Flower ‘ breaking ‘ and leaf mottling. The alternate host is cabbage. Be careful not to raise wallflowers near old cabbage beds.

WILLOW

CANKER

Brown spots on leaves. Small cankers on shoots. Cut away cankered wood and burn it. Paint over the cuts with tar.

RUST

Yellow spots on leaves, stems cankered.

Spray early with Bordeaux mixture.

ZINNIA

SEEDLING BLIGHT

Seedlings die as result of infected seed. Destroy.

GREY MOULD

Serious in greenhouses and in wet seasons. Dust well with TCNB.

06. September 2013 by admin
Categories: Gardening History, Plant Biology, Top Tips | Tags: , , , , , , , , , , , , | Comments Off on TREE AND FLOWER DISEASES

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