Efficacy and rainfastness are the top features for any blight fungicides

UK - April 30, 2004

Rainfastness is the second most important feature of a blight fungicide according to the results of a survey of potato growers and advisors, conducted by Dow AgroSciences. According to the latest results of the survey, efficacy was the top pre-requisite of a blight fungicide with 60% of farmers stating that this is the most important feature, but around 40% said that rainfastness was the next most important feature.

“Farmers clearly want a product that makes the most of the spray opportunities available. This means that they are looking for one that is absorbed onto and into the plant quickly and will resist removal by irrigation or by rainfall. It makes life a lot easier knowing that the product you apply has the flexibility to be applied even in showery conditions and fits easily into irrigation regimes. In the market survey, growers and advisors were also asked which product they thought was the most rainfast and it was Electis* from Dow AgroSciences and Ranman from Belchim that were regarded as being the most weather proof, followed by Shirlan from Syngenta. Based on zoxium and mancozeb, Electis has been proven in the laboratory and in the field to be one of the most rainfast of all blight fungicides.” reports John Sellars, Marketing Specialist for Dow AgroSciences.

Zoxium is very lipophilic — that is, it has low water solubility and high affinity for the leaf wax. It also rapidly penetrates the waxy cuticle layers and then into the leaf so it becomes highly weatherproof. Glasshouse studies in which 100mm of rain was applied showed no decline in blight activity from zoxium compared to when no rain occurred.

This was not the case for the experimental control, fluazinam, which declined from 87% blight activity with no rain to 66% after rain.

Further, trials in France where the percentage blight infection was monitored each day following 40mm of field irrigation, showed that even after seven days, the Electis treatment was showing only 7% infection compared to fluazinam with 81% infection. In the same trials the untreated exhibited 100% infection after the same time period. This demonstrates that Electis became rainfast within one hour, making it a key component of any blight program with flexibility to fit into irrigation programs or in periods of showery weather.