Powdery Mildew

Powdery mildew is a common phytopathogenic infection caused by a wide variety of closely related fungal species that each attacks a specific type of plant.

Powdery mildew infected cucurbit plant http://en.wikipedia.org/wiki/Powdery_mildew

Powdery mildew infected cucurbit plant

Infection with powdery mildew is easily recognised as the appearance of powdery white or grey spots that gradually increase in size on the upper parts of leaves, spreading to shoots and flowers and eventually covering the whole plant. The warm, humid conditions that prevail in glasshouses are ideal for the germination and spread of powdery mildew spores, which can seriously affect commercial and domestic yields of cucumber, tomato and pepper crops, as well as ornamental glasshouse crops such as roses and chrysanthemums.


Measures to prevent powdery mildew infection include using resistant varieties, ensuring that plants are healthy, but not over‑fertilised and avoiding overcrowding with good air circulation around the leaves. Chemical fungicides are commonly applied but not all are registered for the treatment of vegetable crops, and sulphur application, which is a particularly effective fungicide, can have negative effects on biological controls used as part of an IPM scheme.

Eden’s encapsulated terpene products have antifungal activity and the non-toxic nature of the ingredients allows late pre‑harvest and post‑harvest application on protected glasshouse food crops.

Eden Research and Development - Powdery mildew trials

The efficacy of Eden’s products against powdery mildew on glasshouse cucumber crops was tested in 2006. A total of 10 small plot replicated trials were conducted on glasshouse crops including spring‑planted cucumbers in Spain and Greece, autumn‑planted cucumbers in Greece and a courgette crop in Spain. In all trials, Eden products were applied 3‑6 times at 10‑day intervals at 400 mls/ha following the onset of disease. Efficacy against powdery mildew in 7 of the 10 trials was compared with competitor chemical fungicide treatments of triazole‑based Topas ® (used at 35 mL/hL) and sulphur‑based Thiovit Jet ® (at 400 g/hL), both produced by Syngenta Crop Protection, and the results are shown in Figure 1.

Figure 1. Powdery mildew efficacy- data from 7 trials in Europe

Figure 1. Powdery mildew efficacy– data from 7 trials in Europe


Powdery mildew efficacy

Two different Eden products, 2BY and 2EY were both tested at 400 mL/hL against powdery mildew-infected cucurbits grown in a glasshouse environment.

Both products compared well with industry standards Topas and Thiovit Jet.


  • There is a substantial commercial market for powdery mildew treatments, particularly with regards to glasshouse protected vegetable, herb and ornamental crops
  • Eden’s terpene products 2BY and 2EY have shown antifungal activity against powdery mildew of cucurbits that compares well with that of leading chemical fungicide competitors
  • Further small plot replicated field trials are now considered as a priority


For further detailed information on Eden's products, please contact Eden at info@edenresearch.com