Alan has spent almost all his working life in horticulture and now mainly deals with organic and biological controls.
Honey Fungus which attacks the roots of many woody and perennial plants is actually edible. It used to be killed by Armatillox which is no longer available but Jeyes Fluid does have some effect.
Vine weevil is an insect that can feed on a wide range of ornamental plants and fruits, especially those grown in containers. Adult vine weevils eat leaves and the grubs eat roots. The adults can live all year round in conservatories. The adult weevils are active spring to late summer with the grubs taking over until spring. They can be controlled by using nematodes.
Root rot is a fungus like organism causing root and stem base decay and can remain in the soil for a long time. It is primarily a disease of heavy or waterlogged soils. Diseased plants should be destroyed. Prevention is helped by using clean healthy soil or compost and buying certified plants.
Brown rot is a fungal disease of apples, pears, plums, cherries and some other fruit and ornamental trees, causing a brown spreading rot in fruit. It is caused by the same fungi that cause blossom wilt of the flowers and fruit spurs. Whilst there is no specific fungicide available to amateurs potassium bicarbonate will help. Spray on fruitlets several times.
Spider mite is a sap sucking mite that causes a mottled appearance and can cause leaf loss and plant death. They can be controlled with organic sprays or the use of predatory mites. They do hibernate so if growing strawberries indoors remove all leaves in February or March.
Powdery mildews are a group of related fungi which attack a wide range of plants, causing a white, dusty coating on leaves, stems and flowers. Destroy all infected leaves and remove infected shoots. Feeding with a high potash food can sometimes help as will sunshine and circulating air.
Eel worms are foliar nematodes that feed within the plant causing stunted and deformed buds leaves and flowers. There are no pesticides available so remove and destroy all affected plant parts and avoid overhead irrigation as the nematodes use the water film for mobility.
Carrot fly is a small black-bodied fly whose larvae feed on the roots of carrots and related plants, such as parsnip, parsley, celery and celeriac. Sow sparsely to avoid thinning as the flies are attracted by smell. Covering the plants with netting as that is more effective than barriers. Practice crop rotation as the flies can over winter in the soil. Nematodes can be used as a control.
Earwigs are omnivorous, they feed on other small invertebrates and plant material. They can reduce fruit aphid problems but they may feed on flowers and leaves of clematis, dahlia, chrysanthemums and occasionally other plants. They can be trapped by used upturned plant pots stuffed with straw and placed on canes.
Cabbage root fly. The maggots of cabbage root fly eat the roots of cabbages and other brassicas, they can also tunnel into the roots of swedes, turnips and radish. Plants grow slowly then wilt and die as the roots are eaten. There can also be tunnelling into plants. Brassica collars can afford some protection but crop rotation is essential. Nematodes can be used but they can kill non target species.
Slugs are widespread animals which can cause problems in the garden, eating holes in leaves, stems, flowers, tubers and bulbs. They can cause damage throughout the year on a wide range of plants, but seedlings and new growth on herbaceous plants in spring are most at risk. Biological controls are available but they do provide food for hedgehogs and other creatures. They can be collected by hand after dark and beer traps can be used.
Glasshouse mealybugs are common sap-feeding insects found on a wide range of houseplants and greenhouse plants. Mealybugs can weaken plants and excrete a sticky substance (honeydew) on foliage, which allows the growth of sooty moulds. They cannot fly far so are usually introduced on infected plants. There are several biological controls and methylated spirit on cotton buds does work.
Glasshouse whitefly is a common sap-feeding insect, mainly of house-plants and greenhouse plants. They excrete a sticky substance (honeydew), which allows the growth of sooty moulds. Biological controls are available. Sticky yellow pads can be used but they do trap other insects.
Flea beetles. Some species of flea beetle feed on the leaves of all brassicas and related plants, including rocket, radish, swede, turnip and wallflowers. The result is often a peppering of holes particularly on salad leaves. They also attack nasturtiums and cleome. Controlled by using netting or organic pesticides.
Alan has spent almost all his working life in horticulture and now mainly deals with organic and biological controls.
Honey Fungus which attacks the roots of many woody and perennial plants is actually edible. It used to be killed by Armatillox which is no longer available but Jeyes Fluid does have some effect.
Vine weevil is an insect that can feed on a wide range of ornamental plants and fruits, especially those grown in containers. Adult vine weevils eat leaves and the grubs eat roots. The adults can live all year round in conservatories. The adult weevils are active spring to late summer with the grubs taking over until spring. They can be controlled by using nematodes.
Root rot is a fungus like organism causing root and stem base decay and can remain in the soil for a long time. It is primarily a disease of heavy or waterlogged soils. Diseased plants should be destroyed. Prevention is helped by using clean healthy soil or compost and buying certified plants.
Brown rot is a fungal disease of apples, pears, plums, cherries and some other fruit and ornamental trees, causing a brown spreading rot in fruit. It is caused by the same fungi that cause blossom wilt of the flowers and fruit spurs. Whilst there is no specific fungicide available to amateurs potassium bicarbonate will help. Spray on fruitlets several times.
Spider mite is a sap sucking mite that causes a mottled appearance and can cause leaf loss and plant death. They can be controlled with organic sprays or the use of predatory mites. They do hibernate so if growing strawberries indoors remove all leaves in February or March.
Powdery mildews are a group of related fungi which attack a wide range of plants, causing a white, dusty coating on leaves, stems and flowers. Destroy all infected leaves and remove infected shoots. Feeding with a high potash food can sometimes help as will sunshine and circulating air.
Eel worms are foliar nematodes that feed within the plant causing stunted and deformed buds leaves and flowers. There are no pesticides available so remove and destroy all affected plant parts and avoid overhead irrigation as the nematodes use the water film for mobility.
Carrot fly is a small black-bodied fly whose larvae feed on the roots of carrots and related plants, such as parsnip, parsley, celery and celeriac. Sow sparsely to avoid thinning as the flies are attracted by smell. Covering the plants with netting as that is more effective than barriers. Practice crop rotation as the flies can over winter in the soil. Nematodes can be used as a control.
Earwigs are omnivorous, they feed on other small invertebrates and plant material. They can reduce fruit aphid problems but they may feed on flowers and leaves of clematis, dahlia, chrysanthemums and occasionally other plants. They can be trapped by used upturned plant pots stuffed with straw and placed on canes.
Cabbage root fly. The maggots of cabbage root fly eat the roots of cabbages and other brassicas, they can also tunnel into the roots of swedes, turnips and radish. Plants grow slowly then wilt and die as the roots are eaten. There can also be tunnelling into plants. Brassica collars can afford some protection but crop rotation is essential. Nematodes can be used but they can kill non target species.
Slugs are widespread animals which can cause problems in the garden, eating holes in leaves, stems, flowers, tubers and bulbs. They can cause damage throughout the year on a wide range of plants, but seedlings and new growth on herbaceous plants in spring are most at risk. Biological controls are available but they do provide food for hedgehogs and other creatures. They can be collected by hand after dark and beer traps can be used.
Glasshouse mealybugs are common sap-feeding insects found on a wide range of houseplants and greenhouse plants. Mealybugs can weaken plants and excrete a sticky substance (honeydew) on foliage, which allows the growth of sooty moulds. They cannot fly far so are usually introduced on infected plants. There are several biological controls and methylated spirit on cotton buds does work.
Glasshouse whitefly is a common sap-feeding insect, mainly of house-plants and greenhouse plants. They excrete a sticky substance (honeydew), which allows the growth of sooty moulds. Biological controls are available. Sticky yellow pads can be used but they do trap other insects.
Flea beetles. Some species of flea beetle feed on the leaves of all brassicas and related plants, including rocket, radish, swede, turnip and wallflowers. The result is often a peppering of holes particularly on salad leaves. They also attack nasturtiums and cleome. Controlled by using netting or organic pesticides.
Key factors affecting pests and diseases. Humidity, temperature, crop rotation, soil testing and greenhouse cleanliness.
