Leaf spot Diseases is considered one of the most important and dangerous diseases of the vegetative group in sesame, especially in areas where irrigation is carried out by spraying, as these diseases lead in severe cases to the fall of leaves, which represent the food plant of the plant and provide it with the nutrients necessary for its growth. And in this article on your site botanist WORLD of PLANTS, we will review the causes and symptoms of the disease of leaf spot Alternaria and how to effectively combat it to maintain plant health.
Casual pathogens of leaf spot disease
There are many pathogens causing leaf spot diseases such as Alternaria sesami , Cercospora sesami ,Nthosporium sesami , Cylinderosporium sesami. The Alternaria sesame fungus is considered one of the most important fungi causing leaf spot disease under Egyptian conditions, which we will discuss in some detail below :
Alternaria leaf spot disease Alternaria leaf spot
Pathological symptoms Symptoms of altruistic leaf spot disease
The characteristic pathological symptoms appear in the form of small round to Oval spots with a diameter of 1-8 mm pale, grow in size and become dark brown and have overlapping rings of blackish brown color, and when the infection intensifies when environmental conditions are available, especially high humidity, the spots combine with each other to deepen the surface of the affected Leaf, which leads to the drying of the affected leaves and their fall, and the plants become free The leaves are bare, which affects the photosynthesis of plants, as this leads to poor plant growth, which affects the lack and weakness of the seed yield and the oil content as well as the quality .
The spots also appear on the stems, leaf petioles and pods and reach the seeds, which leads to a lack of seed yield and a decrease in the quality of the resulting oil, as well as the seeds become a source of infection in the next season when used as a dressing, and sometimes infection with this fungus in early cases causes the death of the seedlings before or after germination .
Favorable conditions for the emergence and spread of altruistic leaf spot disease
The emergence and spread of this disease is due to high air humidity and its spread is increasing in areas that are irrigated by spraying, where the spores scattered in the air or found on the residues of infected plants provide suitable conditions for germination on the surfaces of the leaves and then penetrate the Leaf cuticle and the occurrence of infection, as well as excessive nitrogen fertilization leads to an increase in the incidence of infection .
Resistance to leaf spot disease Alternaria Disease control
- The cultivation of resistant varieties is the best way to resist leaf spot, market and hornwort.
- Use at least a triple agricultural cycle.
- Burn the remains of infected plants after collection so that they are not a source of infection in the coming seasons.
- Do not overuse and overuse of nitrogen fertilizers with attention to the addition of phosphate and potassium fertilizers .
- Moderation in irrigation with the preference of using the drip irrigation method instead of spraying .
- Taking care of removing weeds while not reducing planting distances by more than 10 cm so as not to increase the plant density per unit area and, consequently, the high humidity around the plants .
- Perform preventive spraying with Micron sulfur at a rate of 250 g /100 L of water or alvaborgard at a rate of 200 cm / 100 L of water or alkoside 101 at a rate of 150 g /100 L of water or Ascor at a rate of 50 cm / 100 L of water with the addition of a Super film at a rate of 50 cm / 100 L of water as a spreading adhesive, at the onset of infection, spraying should be three times with an interval From 10-15 days I have to stop spraying at least 15 days before harvesting .
Pathological symptoms of altruistic leaf spot disease
- The fungus attacks all parts of plants at all stages of growth
- On the leaves appear small watery spots of brown color, round in shape or in the form of a ring
- By increasing the humidity around the plant, the number of spots increases and their size increases significantly
- The spots are probably concentrated around the midrib of the Leaf
- Increasing the severity of the injury leads to the death of the plant
Fight against altruistic leaf spot disease
- Use of resistant varieties
- Disposal of infected plants and weed control
- Early cultivation
- Treatment of seeds with fungal antiseptics
- One of the deification compounds can be used:
- Kobox at a rate of 250 g/100 liters of water
- Or polyram at the rate of 200 g/100 liters of water
- Or copper acrobats at the rate of 150g /100L
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References
- Diagnosis and resistance of Sesame diseases-Kenana online
- Ultralternaria leaf spotAlternaria-Shuri chemicals
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