The goose cress is a popular plant for the rock garden. It is robust and not very susceptible to diseases and pests. Unless you don't take it too seriously with the care.
Goose cress (Arabis) are robust plants that pose few problems for the hobby gardener. Diseases and pests are extremely rare in the vigorous rock garden plants. Even snails willingly avoid the plants.
Care mistakes, such as a location that is too dry or a substrate that is too sandy, can lead to the goose cress being weakened and thus appearing more vulnerable to diseases. Below are some diseases and pests that occasionally affect goose cress.
Diseases & pests on goose cress
Downy mildew
If the goose cress is affected by downy mildew, this will primarily be noticeable on the leaves. Yellowish to brownish spots can be seen on the upper side of the leaves. The undersides of the leaves are covered with a greyish, velvety coating reminiscent of mould. The spots can also spread to the stems in the advanced stage. Over time, the affected parts of the plant die off.
⇒ Combat:
Affected plant parts should be removed immediately. If the infestation is severe, the hobby gardener will not be able to avoid using special fungicides. Particular attention should be paid to the treatment of the underside of the leaves.
⇒ Prevention:
Downy mildew can be prevented by planting the plants at a sufficient distance in the ground. A planting distance of between 20 and 30 centimeters should be maintained.
» Tip: When the temperature fluctuates, goose cress is particularly susceptible to downy mildew. Give the plants garlic broth or the nettle manure described below as a natural tonic.
Aphids
These aggressive pests scarcely spare a plant. An infestation is also evident here from the condition of the leaves. The leaves deformappear ruffled and curled. Bubble-like expulsions are also present in some cases. On closer inspection, the pests can be seen on the undersides of the leaves. There they usually appear in large numbers and crowded together. If the infestation is not detected or is detected too late, the entire plant begins to stop growing and makes a stunted impression.
⇒ Control:
No chemical agents are usually necessary to control aphids. The hobby gardener can manage with spraying with soapy water or field horsetail. Ladybirds and lacewings are natural predators of aphids.
Ball Gnats
If the leaves are deformed and you see gall-like growths and curled leaves, this is probably the work of the gall midge.
» Tip: Thickening of the buds also indicate an infestation with gall midges.
⇒ Combat:
In the event of an infestation, all affected parts of the plant must be removed as soon as possible. This also affects the buds. In order to prevent the spread of the pests, the hobby gardener has to do without the flowers and break out the buds.
White Rust
White rust is a fungal disease found in cruciferous plants worldwide. This disease is particularly widespread in Holland and Flanders. All above-ground parts of the plant are affected. White rust is identifiable as whitish spots or pustules that can spread to leaves, flowers, stems, or pods. The damaged areas increase in size and with a stronger infestation the leaves curl up. The whitish deposits are the result of broken tissue, which allows the white spores to spill out. There is an increased occurrence of the fungus in spring and autumn. It takes about a week from infection to onset.
» Tip: In midsummer, due to the high temperatures, white rust hardly ever occurs.
Temperatures between 10 and 15 degrees are advantageous for the occurrence of the infestation. Once the plant is infected, it cannot be stopped. Preventive measures with commercially available contact fungicides are possible.
Nettle manure for pest control
Stinging nettles in ornamental gardens usually get angry looks and are ruthlessly eradicated. The use of nettles as a pesticide can replace many a chemical product and as a natural fertilizer, as well asPesticides do a good job. Nettle manure is particularly effective against fungi, viruses and various pests.
Hobby gardeners don't have to dig deep into their pockets for this, but can easily make their own nettle manure.
What is needed to make it?
- suitable vessel
- Water
- Clay powder or bentonite
- Stick for stirring
- Gloves
- Grid for covering
The main ingredient is of course nettle. Large and small stinging nettles can be used.
» Tip: The small stinging nettle is generally classified as more aggressive and therefore more effective.
You can use fresh nettles or dried nettles. If possible, the tub used should not be made of metal. Vessels made of clay, earthenware or wood can be used.
Warning: If you harvest nettles fresh, you should wear gloves. The stinging hairs cause an uncomfortable rash.
The nettles are preferably harvested on warm days in May. Flowering plants have the highest combination of active ingredients.
The planter is placed in a sunny and warm place, if possible in a less frequented area of the garden, so that the smell that develops is not perceived as disturbing. Chop up the stinging nettles and fill the container halfway with the chopped up parts of the plant.
» Tip: Add one kilogram of fresh or 200 grams of dried plant parts to ten liters of water.
The vessel should not be filled to the brim with water. Leave a border about four inches high. The vessel is covered with a grating, but not sealed airtight. Over the next few days, the batch will begin to ferment. In the following days you should stir the liquid manure vigorously at least once a day. When about two weeks have passed, the liquid manure takes on a brownish color and no longer foams as much. This is a sign for the hobby gardener that manure can now be used in the garden.
» Tip: The mixture will now be stored in a cooler place and will be used up over the next few days.
Prevent diseases and pests with nettle manure
For preventive use, the nettle manure is used diluted. For use in irrigation water, mix one part liquid manure with ten parts irrigation water. If the liquid manure is to be administered with the spray bottle, add 50 parts to one part of liquid manureWater. Nettle manure is a proven tonic for all types of ornamental plants.
Fight pests with nettle manure
Stinging nettle manure is particularly effective in the fight against:
- Aphids
- spider mites
- Thrips
- Ball Gnats
If you want to use liquid manure for targeted pest control, you need less patience. The approach can be used after just two days. This is exactly when the concentration of nettle toxins is greatest.
» Tip: The effect can be intensified if the nettle manure is mixed with horsetail broth.
Warning: Nettle manure is not suitable for use on crops such as onions, garlic, beans, peas or lettuce.