Sesame

A picture of the roots of a sesame plant suffering from root rot

At all stages of its life, sesame is affected by many diseases, including:

Root rots

Root-rot disease

Casual pathogens

This disease is caused by many fungal pathogens lurking in the soil, including:

Macrophomina phaseolina, Rhizoctonia solani, Fusarium solani, Sclerotium rolfsii, Phytophthora parasitica var. Sesame.

Sesame - the world of plants

Sesame - the world of plants Root rot

Symptoms

Disease symptoms on infected plants are characterized by yellowing, wilting of plants, and the fall of their leaves, along with the ease of removing infected plants from the soil as a result of rot and death of the roots.

The disease symptoms caused by each of the previous fungi on infected roots vary as follows:

Infection with the M. Phaseolina fungus leads to easy removal of the outer peel of the infected root, as small charred black dots that represent the stony bodies of the fungus can be seen beneath the outer peel.

One of the characteristic symptoms of the Rhizoctonia solani fungus is the appearance of blackish-brown lesions with a characteristic suffocation in the area where the root connects to the stem (crown area). The infection covers the entire root and causes the death of the plant when the infection becomes severe.

Infection with the fungus Fusarium solani is characterized by the presence of bright red lines in the longitudinal section of the root, with the presence of reddish-brown rot at the ends of the infected root.

Infection with both fungi Phytophthora parasitica and Sclerotium rolfsii is characterized by the presence of water rot of the root, where the root infected with these two fungi appears as if it is submerged in water, where it takes on a boiled appearance and has an unpleasant odor, then turns into dry rot. The fungus may infect the entire root system or it may be in limited parts. From the root.

The roots may be infected with one of these fungi, some of them, or they may be infected with all of them. The infection of the roots results in the plants becoming weak and stunted as a result of the lack of secondary roots and their wilting. When the infection becomes severe, the plant dies.

Conditions suitable for the emergence and spread of the disease

The emergence and spread of the disease and the occurrence of infection are appropriate for moderate temperature and high moisture content in the soil as a result of heavy irrigation, close irrigation periods, and a high ground water level as a result of poor drainage. Likewise, watering plants at noon when the soil temperature is high, which leads to the irrigation water being hot, which leads to root scalding and death. The infection is seen in the field in the form of spots as a result of the accumulation of irrigation water resulting from the unevenness of the soil surface, while infection with the M. Phaseolina fungus is associated with soil dehydration.

Resistance Disease control

1- Developing constantly resistant varieties, as the resistance characteristic of sesame is not constant.

2- Cultivation of resistant varieties such as the Shandawil variety (3) and the Taqah variety (2)

3- Use at least a triple agricultural cycle.

4- Moderation in irrigation, not flooding, not irrigating in the afternoon, and not being thirsty, to avoid infection with the M. Phaseolina fungus.

5- Avoid excessive nitrogen fertilization and pay attention to phosphate and potassium fertilization.

6- Treat the seeds before planting with one of the seed’s fungal disinfectants, such as Rizolex-T, at a rate of 3 g/kg seed, while using gum arabic, concentration 5%, as an adhesive, at least 24-48 hours before planting.

The cause of disease is the fungus Macrophomina phaseolina Fusaruim spp. Alternaria spp. Rhizoctonia solan

Characteristic symptoms

The fungus attacks the seeds before they germinate, causing them to rot and preventing the seedlings from appearing on the surface of the soil. The fungus can infect the seeds before they germinate, causing them to rot and preventing the seedlings from appearing on the surface of the soil.

The fungus attacks small seedlings and water spots appear on the plant stem in the area of contact with the soil surface, which leads to the seedlings falling asleep and dying. When the fungus attacks large seedlings, a brown, rectangular-shaped spot appears that increases in length and width until it surrounds the plant stem, which leads to the death of the plant.

The infection causes wilting and drying of the shoots.

Its symptoms appear in the form of dark brown ulcers on the roots, causing the death of the seedlings. As the infection progresses, the ulcers spread to the entire root and the plant eventually dies. The infection leads to easy removal of the outer skin of the roots and the appearance of black dots underneath. Increased ground humidity and excessive nitrogen fertilization help the disease to spread. Secondary roots stunt the plants and eventually die.

Control

Control is carried out using the following methods:

    1. Develop resistant varieties and follow a long agricultural cycle (not less than three years).
    2. Burn the remains of infected plants.
    3. Moderation in irrigation and fertilization, and attention to phosphate and potassium fertilization at the appropriate depth.
    4. Planting at the right time.
    5. Sterilize the seeds before planting them.

the reviewer

Leave a Reply

Your email address will not be published. Required fields are marked *

Post comment