Disease pathogen: Colletotrichum lagenarium.
Anthracnose is a common disease, but it puts a special harm on a culture grown in a plastic foil greenhouse. The fungus develops on all ground organs of the plant.
The first signs of anthracnose, in the form of pressed brown spots near the root neck, can be seen in the seedlings. Damage to the stem base, due to an infectious fracture, is rarely the cause of the seedlings' death.
In most cases, the leaves of the cucumber are present (real and semidular). On them it is possible to notice yellowish-brown spots of round shape, in the sizes from 3 mm to 3-4 cm.
On the spots a copper-pink raid of sporulation is formed, which then darkens and becomes denser. This indicates the development of the black micro sclerotia of the fungus, which occurs when the moisture decreases.
The deepened and elongated spots covered with the same spray can be formed on stems and petioles.
The damaged tissues die and crumble, the leaves often break in the places of defeat. Leaves affected by the disease begin to dry gradually, and the fruits are covered with wet ulcers.
On the fruit, there are single or grouped spots and ulnar depressions. The affected fruits are bitter to taste and quickly spoil when transported and stored.
Spores of pathogen spread through the air droplet path. Water and some arthropods play an important role in the spread of the pathogen.
The fungus develops in a wide range of temperatures (from 4 to 30 ° C), but requires high humidity (90-98%). Optimum temperatures for the development of the disease: +22 - + 27°С. In such conditions, the incubation period is 4-7 days.
Infection may be found in the remains of plants and seeds of infected culture.