Introduction
Tomato plant cultivation is very popular among amateurs as well as professional gardeners. Tomato plants when exposed to elements of nature and natural flora of bacteria, viruses and fungi can cause diseases in them. It is known as a fact, to solve a problem you need to understand the problem. When it comes to tomato plant disease and its prevention and cure, identifying the causative agent is very important.
History
Before you start your work on an infected plant, take self protective measure like wearing gardening gloves and using a face mask to cover your nose and mouth. Start by inspecting the tomato itself for any morphological changes like darkened areas, dark spots, cuts or cracks in the skin and discolorations. Now, examine the plant leaves, searching for dark spots, discolored patches which may be light or dark, and dried up yellow patches. Next in line is the stem. Check for any signs of dark or light patches and dried up sections. Diseases that affect the roots are difficult to seek as they don’t manifest externally but as the disease progresses roots become swollen.
Nutritional deficiencies
Like humans, tomato plants can develop nutritional deficiency related diseases. Good, soil and substrate mixture is vital for growing a healthy tomato plant. Some common nutritional deficiencies can be that of Nitrogen, Calcium, Phosphorus, and Magnesium. Deficiency of nitrogen causes the plant to grow slowly, with thin stem, and stunted leaves that have a yellowish purple tint. This problem can be rectified by adding fertilizer to the soil. Calcium deficiency is determined by the evidence of decayed stem tips. Leaves begin to decay, starting stem side first, and discolored brown or purple patches become evident. Decayed blossom end is another vital symptom. Calcium deficiency can be tackled by adding lime to the soil. Phosphorus deficiency presents itself with symptoms of extremely thin shoots and very slow growth. Leaves are droopy, curled, and exhibit a dark purple discoloration. Fertilizers will help resolve this problem. Completely yellow colored leaf with green veins point to magnesium deficiency. One ounce of Epsom salt added to a gallon of water will be a definitive remedy.
Infectious diseases and pests
Diseases that affect a tomato plant can cripple your garden seriously. Early blight is one of them. It is a fungi. Dark rings are formed on the plant leaf and they die out if left untreated. Spraying with copper or sulfur will cure the plant. Late blight is also a fungal infection that kills the plant in a very short time. Greasy spots appear on the fruit and leaves. Copper spray prevents its spread. Southern blight is prevented by using ammonium and calcium rich fertilizers. Verticillium wilt is a fatal condition and the plant needs to be discarded. Septoria leaf spot is treated by using copper spray while Gray leaf spot affected plants need to be discarded. Curly top virus infected plant stops growing and turns yellow. It’s transmitted by beet leafhopper, and controlling this pest protects your plant. Psyllids are pest that feeds on the tomato and while doing so inject their toxic saliva into the plant. Leaves turn yellow, veins become purple and stem shows physical changes. Sulfur spray will help in their control. Flea beetles are dark brown or black colored and are responsible for causing small holes in the leaves as they chew on them.
Permethrin or cabaryl are effective insecticide for control. Tomato hornworm is large green caterpillar with a voracious appetite. They will feed on the leaves, stem, as well as tomato itself. Insecticide sprays are vital in controlling them. Cucumber mosaic virus Stunts growth, leaves become mottled and the plant develop a yellowish hue. No chemical control has yet been developed. Bacterial canker affected plant develop brownish discoloration on leaves and a whitish scabby lesion on the fruit. Destroy the entire batch of tomato plants and restrain from using the same soil for tomato cultivation for a period of 2-3 years. Root rot which is caused by fungi can only be prevented by rotation of crop, soil improvement and proper irrigation. Cold weather and high nitrogen content are the etiology for catfacing. It’s a condition were tomato are misshaped and resembles the face of a cat. Blossom end rot can be easily prevented by practicing proper watering methods and fertilizers. Sunscald is caused by over exposure to sunlight, so reduce the fruits exposure to direct sunlight. Green or yellow shoulders also develop due to over exposure to sun. Employing proper irrigation technique, and the ability to identify diseases at an early stage coupled with the use of proper fertilizers and pesticides will ensure you a health plant, free from tomato diseases.
