Gesellschaft für Phytopathologie mbH Konstanz

We are your partner in the development or assessment of your preparations.

Late blight / Phytophthora infestans

The oomycete Phytophthora infestans is the causal agent of late blight in potato and tomato.

If you are interested to get your preparations tested for efficacy against P. infestans, we will be at your service with our test system.


Disease lexicon


Glasshouse assays on potato

For analysis of the effect of products on Phytophthora infestans, we offer a biotest on potato plants.  Potato plants are cultivated in glasshouse. For assay the preparations are sprayed on the surface of the leaves. Afterwards the plants are inokulated with sporangia of P. infestans. After about 7 days the amount of damaged tissues is analyzed for the first time. After a second analysis the area under disseas progress curve (AUDPC) can be calculated. Compared to untreated control and a chemical standard the efficacy of the preparations against P. infestans can be determined.


Leaf disc assay using tomato leaves

Tomato leaves are cultivated in the greenhouse year round. The pathogen Phytophthora infestans is cultivated on agar plates and induced to form sporangia. Treatment with your preparation is performed by spraying the underside of the leaves. Incubation is carried out on water agar plates at 20°C. After 6 to 8 days, the leaf surface covered with P. infestans mycelium is analyzed in comparison with an untreated control and the chemical standard. The experiment is repeated four times. The percentage reduction in the infection compared to the control treated with water is calculated as the efficiency for each treatment.

Small potato plants in our greenhouse.