TREE AND FLOWER DISEASES
Swollen and malformed reddish blisters on leaves. Spray before buds burst in January or February with lime sulphur. Half pint in 2 gal. water.
Furry grey mould on leaf under-surface. Destroy crippled plants, feed and spray with zineb.
ASTER (Michaelmas daisy)
Browning and withering of leaves from bottom of plant up. Take shortin early spring and plant out on fresh site in April.
Often encouraged by wet conditions. Provide good drainage and water in with Cheshunt compound.
Very serious, attacks stem half-way up and prevents flowering. Also contaminates. Grow resistant varieties.
Brown spots on leaves and on stalks so that branches wilt and die. Cut off affected parts and spray with colloidal copper.
Greyish blotches — in young rooted cuttings. Cut off affected parts and spray with captan.
Yellow spots and streaks but the disease is not important.
Leaves turn yellow and wither. Destroy affected plants and use sterilized soil for the cuttings.
Spray with colloidal copper.
Cauliflower-like growth of leaves. Destroy affected plants.
Spray with Karathane.
BLACK ROOT ROT
Due to wet soil and lack of humus for aeration of the roots.
Leaf mottling and stunted flowers. Destroy plants.
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.
Often serious in southern districts. Spray with Karathane.
Leaves show pronounced striping. Best to destroy heavily infected stock and plant new stock.
Cut off any affected branches and spray with colloidal copper.
Black lesions on corms. Dip in organo-mercurial dust before planting. Plant on a fresh site each season.
Spotted Wilt. Circular brown bands appear on leaves. Destroy plants.
Dust with TCNB dust.
Spray with Karathane.
On bulbous irises, black inky patches on bulbs, which should be burnt.
Onsoft rotting of rhizomes.
Remove dead parts. Use fungicidal dust.
Chiefly on bulbous iris — leaves show mottling and flowers show ‘breaking’. Burn affected plants.
Not usually serious if beds are well cleared of old leaves etc., in spring.
Swollen branches producing white horn-like fruiting bodies containing brown spores. Cut off and burn.
Cut out and burn affected parts.
Orange fungus bodies on the cankered areas. Cut out and burn affected parts.
Blackens young shoots and flowers causing them to wither and droop. Cut out affected shoots.
Spots and brown patches on leaves. Spray-early with Bordeaux mixture.
Mosaic is common. Destroy infected plants and keep down aphids.
Black spots on leaves — not usually serious. Burn old leaves.
Serious in. Spray with zineb. Provide good cultivation.
MICHAELMAS DAISY (see Aster)
Can be serious on young oaks. Spray with Karathane.
Mottling on leaves. Very common on all kinds of primulas. Destroy affected plants.
Cluster cups on leaves. Other host is cocksfoot grass. Destroy affected foliage and spray the plant with colloidal cop-per.
Orange spots on underside of leaf — not very common. Alternate host is spruce. Spray with thiram.
Leaves become pale due to iron deficiency. Apply Sequestrene.
LEAF BLACK SPOT
Spray with captan. Pick off infected leaves.
Remove brown cankered shoots by pruning.
On needles. The alternate host is. Do not, therefore, grow on a site that is near spruce plantations.
Plant collapses. Too much water round roots. Destroy plants.
Flower ‘breaking’ and mottled leaves. Often spread from infected brassicas. Destroy infected plants.
Sometimes serious enough to need spraying of young plants with colloidal copper in autumn.
Due to wet soil conditions.
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.
‘Breaking’ in flowers — plants are not much affected.
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.
Causes ‘breaking’ in flower petals. Affected plants should be destroyed.
Swollen blisters on shoots, and leaves contain black powdery spores. Spray Bordeaux mixture after destroying affected plants.
Occasionally serious. Spray with zineb.
Frost injury common on soft-grown plants.
Flower ‘ breaking ‘ and leaf mottling. The alternate host is. Be careful not to raise wallflowers near old cabbage beds.
Brown spots on leaves. Small cankers on shoots. Cut away cankered wood and burn it. Paint over the cuts with tar.
Yellow spots on leaves, stems cankered.
Spray early with Bordeaux mixture.
Seedlings die as result of infected seed. Destroy.
Serious in greenhouses and in wet seasons. Dust well with TCNB.