Thresholds of economical harmfulness of stem canker *

Growth stage of rapeseed plant

Tresholds of harmfulness
(% of infected plants)

Comments

- 2 to 8 leaves to fully shaped rosette in the autumn

20

Spots with fungal fruiting bodies on the surface

- rosette regeneration and the beginning of stem shaping to grow into the flowering sprout

10-15

Spots on the leaves, necrosis on the sprout. Development of the disease is accompanied by frequent rainfall and plant damage by pests. Necrosis of root neck or on the stem base as well as on the leaves.

* Possible thresholds were calculated by dr Marek Korbas (Institute of Plant Protection, Poznań) based on the results of experiments performed at the Field Experimental Station in Winna Góra and the results of field observations performed by rapeseed breeders and personnel of the Research Center for Cultivar Testing.