Lack of Light and High Humidity Make Plants Sensitive to Pathogens
Especially in autumn it is important to keep an eye on the internal plant quality. Shortage of light and the humid climate cause sensitivity of the small plants to, mainly, plant pathogenic fungi.
Light is the base of a good internal plant quality. Especially during dark months the internal plant quality asks for attention. Be sure you start with good plant material.
The high humidity during autumn makes the crop soft and weak. Soil pathogens, like Phytophtora and Pythium flourish better in humid circumstances. A weak crop is more sensible to these fungi and pathological insects. Sciara, e.g., damage root tips and therefore water and nutrients cannot be taken up. These damages also give the pathogens an entry to the plant. Millipedes do not harm a strong crop. But in autumn the plant grow decreases while the millipedes get bigger and eat more and more. Then, all at once, the plant can collapse.
Because of the combination of low temperature and little light it takes time for the roots of the young plants to grow. That also means that the plants have more time to get attacked by pathogens. Besides, the plant cells are weaker by which they collapse more easily by root pressure. Be sure of a good climate by which the crop can evaporate optimally. An active crop can resist an attack of pathogens much better. Heating is the best way to prevent fungi!
Diseases of plant material
In the last years the number of bacterial diseases that is brought into the glasshouse by the young plant material is remarkable. Examples are Clavibacter in tomato, Agrobacterium in rose and Xanthomonas in poinsettia. The mother plant does not show symptoms of infection because of the good climate and sufficient (artificial) light. Transportation to the production greenhouse causes plant stress by which the crop is more sensitive to those bacterial pathogens. Just than the symptoms become visible!
If you want to know more about these pathogens please feel free to contact us.