With the observance of agricultural engineering and proper care, petunias rarely get sick. However, a smart gardener acts according to the principle: “Forewarned means armed”.
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How to recognize: the disease affects the shoots of petunias from the beginning of seed germination. The root neck darkens, a black constriction appears at the bottom of the stem. With high humidity in 4–6 days, the blackened part of the stem softens and it cracks. Shoots wither and fall. Causes: thickened crops, sowing in too early a time, high humidity of the soil and air, high acidity of the soil.
Prevention and control measures: observe the sowing dates, do not thicken the crops, do not use too heavy or acidic substrate. The soil prepared for sowing should be disinfected with a solution of potassium permanganate (3 g per 10 liters of water). Seedlings in peat tablets are practically not damaged by the black leg, the tablets are sterile and impregnated with a fungicide. When a black stalk appears, it is necessary to spray the plants and shed the soil with a suspension of preparations containing mancozeb, metalaxyl or oxadixyl in a ratio of 20–25 g / 10 l of water: “Ridomil MC”, “Ridomil Gold MC”, “Profit”.
Another way: Remove all affected plants, and pour the remaining seedlings with 1% Bordeaux liquid or potassium permanganate solution (3 g per 10 l of water).
Gray and white rot
How to recognize gray rot: light brown spots appear on leaves, stalks and flowers, which are then covered with a gray fluffy patina. The affected parts of the plant first fade and then rot, turning into a brownish mass with a gray bloom.
The reasons: too thick sowing and planting, high humidity, low temperature (below +14 ° C), excess nitrogen fertilizers, lack of light.
Prevention and control measures: Avoid excessively heavy crops and plantings, excessive irrigation, too low temperatures.
Regularly remove the affected parts of the plant and plant residues that serve as an additional source of infection, and also increase the proportion of phosphate and potash fertilizers in the feedings. The biological product “Integral” (25 ml / 1 l of water), chemical preparations “Skor” (2 ml / 10 l of water) and “Maxim” (2 ml / 1 l of water) will help.
How to recognize white rot: on moist brown spots, which in wet conditions are covered with a white bloom of mycelium. The affected tissues soften and turn white. A white mycelium forms on the surface and inside the stem, on which black
breeding organs of the fungus.
The reasons: excessively thick plantings, low temperature, high humidity and untimely removal of affected parts of plants. The fungus can spread throughout the flower garden by spores settled on a person’s hands and clothes when caring for plants.
Prevention and control measures: deep digging and liming of soil, timely removal of affected parts of the plant. When the first signs of the disease appear, treatment with biological (“Integral” - 5 ml / 1 l of water, “Fitosporin-M” - 4–5 g / 1 l of water) or chemical (“Maxim” - 2 ml / 1 l of water) preparations is necessary. .
How to recognize: the base of the stalk turns brown and rotten. The plant fades and subsequently dies.
The reasons: high humidity, cold nights with heavy dews.
Prevention and control measures: do not thicken the crops, regularly air the seedlings. After transplanting the seedlings into the ground, precautionary treatments with preparations based on mancozeb, metalaxyl or oxadixyl can be carried out in a ratio
20–25 g / 10 l of water: “Ridomil MC”, “Ridomil Gold MC”, “Profit”.
How to recognize: on rusty-brown spots on the leaves, first rounded, then elongated with concentric zones. Fruiting of the fungus is formed on the light part of the spots. Affected leaves wither and dry.
The reasons: mechanical damage, high humidity.
Prevention and control measures: compliance with agrotechnics, preventive treatment (spraying) with copper-containing preparations with an interval of 7–10 days (“Kartotsid” - 50 g / 10 l of water, copper chlorine - 40 g / 10 l of water, “Oxyhom” - 20 g / 10 l of water) .
How to recognize: the upper part of the leaves is covered with a whitish bloom, then the spots spread to the underside of the leaves and cover the plant with a solid bloom. This prevents the normal process of photosynthesis, because of which the leaves curl and dry, the buds do not bloom.
Control measures: remove and burn the affected plant, thin out thickened plantings and reduce the dose of nitrogen fertilizer. Spraying garlic infusion (25–30 g per 1 liter of water) or infusion of mustard (2 tbsp. powder per 10 l of warm water) helps in the seedlings. On adult plants use drugs "Skor", "Bravo", "Topaz", "Previkur."
Pests should especially beware of the growing stage of petunia seedlings.
How to recognize: deformation of leaves and young shoots of petunia, local chlorosis, general wilting of plants. The petals are covered with honeydew and black fungus. Buds wither, including from viral diseases, which are carried by aphids. Aphids satellites are ants.
Prevention and control measures: attraction of ladybirds to the site, regular washing of the leaves with water or with a solution of laundry soap (1: 6), fighting the ants on the site. Chemicals: Aktara (0.5–1 g per 1 l of water), Confidor, Decis (0.1–0.5 ml per 1 l of water), Fufanon (1 ml per 1 l water).
Aphids on petunias
How to recognize: on the damaged leaves, fuzzy yellowish spots appear and gradually increase. Perhaps a slight twisting of the leaves. With a strong damage leaves dry, shoots can be deformed. On the upper side of the leaves, growing under damaged, there is honeydew and then black fungus. Touching a populated plant, you can
See how disturbed adult whiteflies soar from leaves and shoots.
Prevention and control measures: regular washing of the leaves with water or a solution of household soap (1: 6). Destruction of weeds on a site. Transferring plants to a cooler room - whiteflies do not like lowering the temperature. Capture using sticky tape traps. When dealing with whiteflies, a single treatment is usually not enough. It takes 2-3, better drugs from different chemical groups. A weekly waiting period is required between treatments. Most commonly used are “Mospilan”, “Applaud”, “Aktar”, “Biotlin”, “Iskra Zolotuya”, “Tanrek”, “Commander Maxi”, “Fufanon”.White fly
How to recognize: on pollen spilling from stamens on flower petals. Brown, dried up empty anthers, thickened pistil bases, too rapid flowering of plants. Petals of flowers and leaves are covered with small white (pricks) and black (excrement) specks. The injections form scattered small yellow or discolored spots, strokes, stripes, which eventually merge, and the surface of the sheet acquires a brilliant silver-white color. Later, the injection sites become brown or black.
Prevention and control measures: destruction of weeds and plant residues in the area. With a high number of thrips, cut off the plants early until the pests have moved to the lower part of the stems. Biological preparations: "Fitoverm", "Fitoverm-M", "Vertimek", "Akarin". Chemical preparations: Aktara, Konfidor, Intavir.
How to recognize: the leaves brighten and become covered with small yellow dots (from pricks), then turn yellow and dry, covered with cobwebs.
Prevention and control measures: timely and sufficient nutrition of plants with fertilizers, ventilation and watering. Destruction of weeds around and inside greenhouses, hotbeds, beds. During the growing season spraying "Akarinom", "Bitoksibatsillinom", "Fitoverm". Chemicals: Actellic, Kemifos, Neoron, Apollo, Demit.Spider mite
How to recognize: small yellow punctures appear on the leaves, later - bright drawings-moves of the pest. Dark brown pupae of miners ripen on the leaves and then fall to the ground, where they pass the next phase of development.
Control and prevention measures: When buying ready seedlings carefully inspect the plants. The affected plants are immediately removed, until insects are released from the pupae. The treatment is carried out with the drugs "Actellic", "Karbofos", "Fufanon".
How to recognize: oblong holes in the leaves and flowers. There is no significant harm to the slugs, but the eaten leaves and flowers spoil the appearance.
Prevention and control measures: before the slugs appear, scatter freshly quenched lime or superphosphate on the soil surface.
Use traps (boards, saucers with beer). For severe lesions, use aldehyde.
When identifying fungal diseases
In the flower beds of petunia cut by a third, cut out all the dry and damaged shoots. Treat plants and soil with systemic fungicides: “Skor”, “Topaz”, “Prognosis”, “Fundazol”. When the plants start to recover, re-process them with biological fungicides: “Fitosporin”, “Alirin”. Be sure to disinfect the vases and containers before planting seedlings.