Diseases and pests of nightshade vegetables
Tomatoes are attacked by the so-called. non-parasitic diseases, to which it belongs:
1) dry rot of the tops of the fruit – initially there are small dark green spots on the tops of the fruit, gradually increasing, browning and slightly sagging (under the stain, the flesh is dry rot and the tomatoes fall off in hot weather); prevention consists in watering the plants regularly and sufficiently, avoiding over-fertilization of plants, especially nitrogen, and spraying endangered tomatoes with 0.5% calcium chloride or 0.5% calcium nitrate;
2) leaf curl upwards – occurs in strong sunlight and a water shortage at the same time, and when plants are cut and topped in very sunny weather;
3) cracking fruit – occurs in cases: heavy rains following a period of drought and excessive phosphorus fertilization of plants.
Tomatoes are also attacked by numerous parasitic diseases, and several of them in particular.
Viros. Factors, viruses are pathogenic: Nicotiana virus 1, melon virus 2, Tomato virus 3. The first virus causes various symptoms in plants, how: green and yellow mosaic on the leaves, brown necrotic streaks and spots on the stems, leaves and fruit; and changes in leaf shape, which thread and resemble fern leaves. The second virus causes mosaic and sometimes, like the previous one, deformation of the leaves. A third virus causes ring blotch on leaves and fruit. All these viruses, transferred to plants by insects, tools, clothes and hands of people working with tomatoes, inhibit the growth and yielding of plants. Prevention of these diseases consists in disinfecting the soil used for the production of seedlings, using seeds harvested from healthy fruit, rejecting diseased and suspicious seedlings and removing diseased plants, which you should smoke.
Tomato bacterial cancer. The first symptom of this disease is wilt of individual leaflets; later entire leaves and side shoots wilt, and finally the whole plant. Browning of vascular bundles is visible on the cross-section of the stems. In the event of a disease, diseased plants must be eliminated, and removal of side shoots and topping should be done by hand (not with a knife). It is imperative to stop on 2-3 years of growing tomatoes on the spot, in which the disease occurred.
For diseases of fungal origin, the most common attacking tomatoes, belong sequentially.
Gangrene of the base of the tomato stalk. Diseased plants wilt, their lower stem turns brown and becomes narrower. Green and ripening fruits are also attacked, with brown spots, surrounded by a wide, a white border. Rainy and cool weather favors the development of the disease. Its control consists in removing strongly infested plants; therefore, the plants should be regularly inspected from the end of June to mid-July. In order to avoid the spread of gangrene during the uprooting of the plants, the stems of diseased plants should be sprayed with Sadoplon before this treatment. 75 in concentration 0,4%.
Potato blight is a very common and damaging disease. There are brown or black spots on diseased leaves, and the leaves themselves dry quickly. Also, brown spots appear on the fruit. The control consists in spraying co 10-14 days, in the case of early varieties – already in June, when the plants set the fruit, 0,6% more ridiculous 45 WP.
Tomato septoriosis. This disease can occur in tomatoes at all stages of development. Many are formed on the leaves, minor, with clear contours, brown or gray spots with a darker edge. In the center of the stains, which dry and glow, dark brown or black dotted hills are formed, better visible from the underside of the leaf. Petioles and stems are also often infected. Combating it is similar to potato blight.
Tomato alternaria. This disease occurs in potatoes, tomato, peppers and eggplants. The affected leaves develop dry brown spots, gradually growing in warm and humid weather, covering a significant part of the leaf blade; these leaves dry up, but they do not fall. On fruit, most often at the stalk, dark ones arise, slightly recessed spots, later covered with black, velvety bloom. This disease is controlled in a similar way to potato blight.
Pests attacking plants of this group include aphids, which are dangerous mainly due to the transmission of viruses, and the Colorado potato beetle. The Colorado beetle is a widely known beetle, found both on potatoes, as well as tomatoes and other vegetables from the nightshade family. Colorado beetles (yellow with black stripes), which wintered in the soil, they come to the surface in early May and lay their eggs on the underside of the leaves. Raspberry red larvae hatch from the eggs, which, together with the beetles, completely eat up the leaves. Fighting is about collecting and destroying beetles. Spraying is used with a massive occurrence of the Colorado beetle, after first noticing beetles, one of the following preparations: Cymbusz 25 EC – 0,015%, Determined 2,5 EC – 0,035%, Ripcord 10 EC – 0,04% in Unden 50 WP – 0,15% (up to three weeks after planting the seedlings into the ground).