Crops
Other problems
Although rare and occuring mainly in traditional nurseries, the polyphylla (or "Frenching") is a complex syndrome, sometimes causing significant damage. It results in intense yellowing of interveinal tissues; however, the veins remain green (figure 1), and leaves are often filiform (figure 2). For more information about this problem, please, see also the section Abnormal leaf shape of mature plants as well as the Abnormal leaf colour.
There are countless examples of parasitic and non-parasitic (abiotic) diseases observed in nurseries. We have presented the most common ones. If you see symptoms not presented in this section, we recommend you to view the topic of Field diseases. In fact symptoms caused by pests are frequently quite similar on seedlings and mature plants.
Growers should be aware that the seedlings are extremely sensitive and depend on the care and comfort the producers are willing to provide. To help you with this task, we recommend you carefully read and put into practice the measures presented in the section Protection measures to be adopted in nursery.
Figure 1
Figure 2