|ISHS Acta Horticulturae 877: VI International Postharvest Symposium
EVALUATION OF THE NANOSILVER COLLOIDAL SOLUTION IN COMPARISON WITH THE REGISTERED FUNGICIDE TO CONTROL GREENHOUSE CUCUMBER DOWNY MILDEW DISEASE IN THE NORTH OF IRAN
|Authors: ||S.V. Alavi, A.A. Dehpour|
|Keywords: ||Pseudoperonospora cubensis, Nanocid, Mancozeb, dithiocarbamates|
Downy mildew is the most important disease of greenhouse cucumber in the north of Iran.
Some registered fungicides were released to control the disease in recent years.
Mancozeb is the major fungicide that is used for the disease control in this area, but as in the other dithiocarbamate fungicides group, there are main application problems including the residues on the crop and environmental pollution.
A nanosilver colloidal solution with antimicrobial properties is used in various food industrial products with enough safety for humans and the other mammals.
It has not been tested for control of the disease yet.
From 2007-2008, the registered fungicide, Dithane M-45 (Mancozeb) and the nanosilver colloidal solution (Nanocid L2000) were evaluated for control of the disease, caused by Pseudoperonospora cubensis. Four treatments, including distilled water (control treatment ), Nanocid L2000 at 50 and 100 ppm and Mancozeb at 2000 ppm rates, were established to evaluate their ability to control the disease.
The treatments were arranged in a randomized complete block design with five replications per treatment and 9 local cucumber cultivar (sensitive to downy mildew) plants per replication.
Artificial inoculation was done with the sporangia suspension (8 sporangia per micro liter) sprays on eight leaf stages and the treatments were initiated seven days later, when the initial symptoms appeared.
The two subsequent applications were made 7 and 14 days after the first sprays.
Disease severity was measured six times (on a weekly basis) after symptoms of downy mildew developed, by estimating the percent of infected leaf area per plot.
Mancozeb at the 2000 ppm rate was the least effective treatment (24.4%). Nanocid L2000 at the high rate (100 ppm) provided the best control and significantly reduced the disease severity rating (7.3%). Nanocid L2000 at the low rate (50 ppm) was effective (10.6%) less than the high rate.
There was no significant difference between the low rate of Nanocid L2000 and the Mancozeb treatments.
There were no symptoms of phytotoxicity for any treatment.
This is the first report of nanosilver solution effectiveness on greenhouse cucumber downy mildew disease.
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