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Because pelargoniums
have many florets that make up the flower head they are very prone to grey
mould (Botrytis), particularly in damp or wet weather. Eventually this
can lead to further troubles with the stem, when brown soft rot also occurs.
Make sure that faded blooms are removed by snapping the entire
stalk from the plant..
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Oedema is a condition were the leaves appear
distorted or have small growths on the underside. This is common is
greenhouse plants and several factors can cause this problem, including
over-watering or high humidity. Reduce watering and improved ventilation
to remedy this problem.
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Leaf spots are very common and widespread on
pelargoniums. Possible causes are bacterial or fungal infections, resulting
in lesions on the leaves and blackening of stems. The problem seems
to be more apparent in over crowded greenhouses. Avoid over-watering,
damp conditions - improve ventilation.
Snails and slugs cause slight damage to pelargoniums, mainly young plants, by feeding on the stems and yound leaves. This occurs mostly during wet weather. Damage can be similar to that cause by caterpillars snails and slugs leave a distinctive 'slime trail'. Vulnerable or specimen plants should be protected by placing course grit or eggshells around the pot. Alternatively use slug traps or pellets, sprinked sparingly.
This is a common and serious disease that affects pelargoniums, although it should not be confused with the rust that attacks fuchsia's. The diseases spread to the UK, from its natural habitat in South Africa, in the mid 1960's. This disease only affects Zonal pelargoniums. The visible signs are similar to that of fuchsia rust; brownish yellow pustules which develop on the underside of leaves. In severe attacks there may be leaf fall which seriously affects the plants health, resulting in lower flower production and fewer shoots. Remove and destroy all infected leaves and spray with a systemic fungicide. Pelargonium rust is specific to that species and will not attack neighbouring plants of any other genus, such as fuchsia's.
During the summer months, when caterpillars are active, you will almost certainly find the distinct holes that have been eaten from the leaves - minus the slime trail! These are normally small holes, central to the leaf, although the edges are also eaten. Some growing tips of shoots may be pulled together when the caterpillar uses silk to join the leaf tips - it can then feed in relative safety. Remove and destroy any caterpillars that you may find or spray the plant with a systemic insecticide.
Various viruses attack pelargoniums but the commonest is leaf curl virus, although the leaves do not actually curl but are in fact pale yellowish spots, not to be confused with rust which attackes the underside. It is only later on in the attack that the leaves take on a curled appearance. symptoms of this disease usually appear in the spring on over-wintered plants and cuttings taken from last years plants. New foliage is rarely affected. Cuttings that have been taken the previous autumn will show symptoms of this disease and may appear more intense in hot, dry weather. The problem is believed to be soil borne. All badly affected plants should be destroyed.
Black leg is a disease, aptly named, which affects cuttings and young plants. The blackening of the stems spreads upwards from soil level and the affected tissue shrivels and looks pinched, while leaves wilt and shrivel. The plant or cuttings may also become unstable and are prone to fall over. Eventually the plant is so weakened that it will die. Careful husbandry can help eradicate this problem, make sure that pots and trays are cleaned and disinfected before use and compost can be steralised. Cuttings should only be taken from healthy disease free plants and dipped in a fungicide. Clean water, tepid if used from a tap, should be used. Avoid using water that has been stored in dirty rain butts. Keep plants well ventilated whilst in the greenhouse.
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Snails and slugs cause slight damage to pelargoniums, mainly young plants, by feeding on the stems and yound leaves. This occurs mostly during wet weather. Damage can be similar to that cause by caterpillars snails and slugs leave a distinctive 'slime trail'. Vulnerable or specimen plants should be protected by placing course grit or eggshells around the pot. Alternatively use slug traps or pellets, sprinked sparingly.
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This is a common and serious disease that affects pelargoniums, although it should not be confused with the rust that attacks fuchsia's. The diseases spread to the UK, from its natural habitat in South Africa, in the mid 1960's. This disease only affects Zonal pelargoniums. The visible signs are similar to that of fuchsia rust; brownish yellow pustules which develop on the underside of leaves. In severe attacks there may be leaf fall which seriously affects the plants health, resulting in lower flower production and fewer shoots. Remove and destroy all infected leaves and spray with a systemic fungicide. Pelargonium rust is specific to that species and will not attack neighbouring plants of any other genus, such as fuchsia's.
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During the summer months, when caterpillars are active, you will almost certainly find the distinct holes that have been eaten from the leaves - minus the slime trail! These are normally small holes, central to the leaf, although the edges are also eaten. Some growing tips of shoots may be pulled together when the caterpillar uses silk to join the leaf tips - it can then feed in relative safety. Remove and destroy any caterpillars that you may find or spray the plant with a systemic insecticide.
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Various viruses attack pelargoniums but the commonest is leaf curl virus, although the leaves do not actually curl but are in fact pale yellowish spots, not to be confused with rust which attackes the underside. It is only later on in the attack that the leaves take on a curled appearance. symptoms of this disease usually appear in the spring on over-wintered plants and cuttings taken from last years plants. New foliage is rarely affected. Cuttings that have been taken the previous autumn will show symptoms of this disease and may appear more intense in hot, dry weather. The problem is believed to be soil borne. All badly affected plants should be destroyed.
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Black leg is a disease, aptly named, which affects cuttings and young plants. The blackening of the stems spreads upwards from soil level and the affected tissue shrivels and looks pinched, while leaves wilt and shrivel. The plant or cuttings may also become unstable and are prone to fall over. Eventually the plant is so weakened that it will die. Careful husbandry can help eradicate this problem, make sure that pots and trays are cleaned and disinfected before use and compost can be steralised. Cuttings should only be taken from healthy disease free plants and dipped in a fungicide. Clean water, tepid if used from a tap, should be used. Avoid using water that has been stored in dirty rain butts. Keep plants well ventilated whilst in the greenhouse.
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