Hello friends of the farm is this opportunity I am going to talk about the blight by Phomopsis, which produces the fungus Phomopsis vexans, the eggplant and which is an important disease that occurs basically on its fruits and sometimes on the leaves and the stems.
The most frequent and notorious symptom is fruit rot. The lesions in the fruits of the eggplant are that they have sunken appearance; they are discolored and soft, surrounded by a margin of black spore producing bodies, the lesions begin forming pale, sunken and oval areas on the surface of the fruit. These areas become larger and more sunken gradually.
The lesions are so large that it is impossible to market the fruit. The bodies that produce fungal spores form concentric circles within the lesions of the fruit. If the conditions are dry, the infected fruit withers and mummifies, turns black and remains hanging from the plant.
In the leaves the symptoms begin in the lower ones, being more noticeable in young plants. Small and circular necrotic spots are produced, light brown to olive, with the center lighter; finally they turn brown with a dark margin and black dots in the center. The very affected leaves eventually become chlorotic and die. Another cause of death of the leaves is the presence of lesions in the midrib and petioles
The leaves and stems can also be affected. Older leaves are more susceptible to infection. In general, lesions on leaves and stems are circular, gray or brown and develop a light colored center. The bodies that produce spores called pycnidia appear in the center of the oldest lesions, in the form of black grains embedded in the host tissue. The affected leaves may turn yellow and detach prematurely. The infection in the foliage is less important than the infection in the fruit.
Seedlings infected with blight by phomopsis have dark brown lesions that turn gray in the center, just above the soil line. The time comes when these lesions surround the stem in the form of rings and kill the plants.
SURVIVAL AND DISSEMINATION
The phomopsis fungus is favored by hot and humid weather. The optimum temperature for the growth of the fungus is 29 ° C and grows well up to 32 ° C.
The disease survives in the intervals between crops, on the seeds and stubble that remains in the soil. If the season in which it is not cultivated is very short, this will increase the chances of survival of the pathogen.
The disease occurs when the spores are released from the bodies that produce the fungal spores and are dispersed by the splashes of rain, insects and contaminated equipment. The main form of dissemination is by rain splashes. Usually, dissemination by wind is considered minor. The spores germinate quickly when the stems and leaves are moist.
PREVENTION
The management of the disease is complex because the eggplant is susceptible throughout its cultivation cycle.
It is recommended to rotate crops of three years or more between each aubergine crop. This tactic must be accompanied by the incorporation into the soil of crop remains and the elimination of broadleaf weeds, some of which may eventually host the pathogen. The rapid destruction of waste after harvest will help reduce the initial inoculum.
It is recommended drip irrigation or furrow.
In necessary cases, especially during rainy periods.
It is necessary to establish a program with a protective fungicide to maintain yield and quality. There are several cupric fungicides labeled for this purpose. Some new fungicides have been registered for eggplant, but its effectiveness in combating fruit rot by phomopsis is unknown. If the disease is identified in the field, a recommended fungicide should be applied. It is difficult to manage the disease with sprayed fungicides because the smooth skin of the fruit prevents the sprays from adhering well.
Fungicides are most effective when combined with integrated pest and disease control strategies.
Source:
http://www.patologiavegetal.unlu.edu.ar/?q=node/50#PHOMOPSIS
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