If you correctly observe all the conditions of begonia cultivation, then the plant is slightly affected by diseases and pests. In most cases, diseases and pests of begonias are observed in the greenhouse and under adverse conditions.
Diseases that can affect begonia
Gray rot affects begonia and spreads at high temperature and high humidity. On the leaves, shoots and flowers of the plant watery white spots with a grayish bloom are formed. In consequence, these spots are covered with brown wet rot. The stems of the plant in this case rot, and the leaves turn black and twist. To stop this disease, the plant needs to be sprayed with a copper-soap mixture (2 grams of copper sulfate and a solution of water with laundry soap - 20 grams per liter of water). In case of severe damage to the flower, it is recommended to use a fungicide.
Harmful to the plant powdery mildew. It affects the entire plant (aboveground part). First appear on the leaves stains with a white touch, after the plaque spreads to the entire plant. The leaves twist and gradually wither. The room where the flower grows should be ventilated and well lit. To get rid of this disease, apply the spraying of the plant with a copper-soap solution - a tar soap dissolved in a liter of water (20 grams) and 2 grams of copper sulfate. Also, a soda solution (per liter of water 5 grams of soda) is also effective. The plant is also sprayed with a solution of potassium permanganate (5 grams per 10 liters of water).
When the begonia defeats a bacterial patchiness, glassy small watery spots form on the underside of the leaves. With the spread of the disease, the leaves become brown, and the flowers and petioles of the leaves turn black. In this case, the affected plants must be destroyed, the soil should be disinfected. To prevent bacterial blotchiness, begonia should be sprayed with a suspension of copper chloride (0.5%). Repeat this treatment in two weeks.
Dangerous pests for begonias
For begonias, pest control is a dangerous pest. This is a small insect (3-4 mm long). The female is wingless, motionless, with sucking-pricking mouth organs. It is covered with a light brown shield of waxy secretions. The insect larvae are quite mobile until they attach to the plant. In most cases, these insects inhabit the veins and edges of the leaves, stems and petioles, as a result of which the leaves are deformed and discolored. If the pests have spread strongly, begonia is covered with sugary isolates. On such deposits, a dark raid and sooty fungi can spread. The affected plant blooms badly and grows. In conditions of a greenhouse, such pests reproduce year round, giving 3-4 generations.
At home and in garden plots, the following measures are taken to combat mastitis. Manually, with a soft brush, the plant is cleaned and washed with infusion of pyrethrum or garlic (10 grams per liter of water). After a couple of weeks, the treatment is repeated. In the greenhouse begonia is sprayed with a solution of 0.1% hostakvik, 0.1% actinel, 0.2% chlorophos. The treatment is also repeated against the larvae after 2-3 weeks. The treatment should be conducted from April to September.
The whitefly is quite dangerous for begonia. It is a small insect that damages the leaves. The larvae deposited by the female are fixed on the reverse side of the leaf. From begonia they suck the juice, as a result, the leaves turn yellow and fall from the flower. Effectively to control the whitefly, a soap solution (40 grams per 10 liters of water) is used. Spray the plant regularly, until the pest is completely destroyed.
Young shoots, flowers and leaves begonia damages the aphids, which sucks the juice from the plants. In consequence, leaves, along with buds and flowers fall off. Aphids also spread on the underside of the leaves, leaving the sugar secretions behind them. Against this pest can apply infusion of potato leaves (for 4 hours, insist a kilogram of leaves in 10 liters of water). Effective against aphids is a solution of household soap (10 liters of water 200 grams of soap). You can also use infusion of onion peel (10 liters of warm water and 200 grams of peeled onions). You can dissolve 10 liters of warm water with 100 grams of garlic and 100 grams of onions. Spray the plant with this solution is recommended three times.