The geranium belongs to the genus Geranium and is characterized by five equal petals and a great variety of colors. It is a welcome guest of our balconies for the joy of its petals and for the simplicity of the care it needs, so much so that it survives even on the balconies of the blackest thumbs. The geraniums need a lot of water but not that they stagnate; they have strong roots which makes them suitable for any type of soil, finally the ideal temperature for them is around 25 degrees, but they can withstand up to 15 under which it is good to keep them sheltered and above all away from drafts. Unfortunately, even geranium is subject to problems, due essentially to three types of pathogens: fungi, bacteria and insects.
The main causes of fungal diseases are nitrogen fertilization and watering, when they lead to water stagnation. These types of diseases occur especially in spring - with flowering and humidity - and in summer - when it is necessary to water the plant daily. The main types are: rust, gray mold and rot. Rust presents with yellowish spots on the leaves: it is dangerous because it can extend to the neighboring plants. As the disease progresses, the leaves dry out and fall. The gray mold is recognized by dark spots on the leaves of the plant and is caused by nitrogen fertilization. The rot gives a black color to the branches of the plant; It is caused by water stagnation and can be lethal if it hits the roots. If an illness is taken at the beginning, it is enough to change the earth in a pot for better drainage. Otherwise it is good to rely on chemical fungicides.
Bacterial diseases are caused by pruning errors or uninfected tools. Geranium is not affected by many bacterial pathologies, but the most dangerous and lethal is Geranium bacteriosis. When a plant is affected by the bacteriosis of the geranium, there is a yellowing of the leaves and curling, until the fall of the same. Treatment methods are drastic, especially to prevent it from spreading to other plants. The plant affected by the bacterium is good to be eliminated, burning it away from other plants. The soil must also be removed and the pot cleaned and disinfected. In case of cultivation in soil, it must be disinfected with copper before it can be reused.
Geranium diseases: Insects.
Geraniums can be affected by phytophagous insects, which feed on the plant and signal their presence by secreting the pheromone. Among the most widespread insects there are aphids, cochineal and red spider mite. These attack the leaves: the aphids attack to reach the sap, the cochineal covers the surface and finally the red spider mite causes its yellowing by weaving the canvas at the base of the leaf. Chemical solutions are recommended only when the disease is widespread: if taken at the beginning there are effective alternative methods, above all the cleaning of the plant with alcohol-soaked cotton balls. In the case of cochineal a thorough cleaning of the leaves, first with the cotton balls then sprinkling water and neutral soap, enough to stop it. As for the red spider mite, it is good to remember that he loves poorly humid environments: after cleaning the leaves, use the sprayer several times a day to keep them moist, he will stop the spider. Soapy water and moist environment are also effective against aphids, so careful cleaning is sufficient.