Dow Agrosciences is recommending the inclusion of the protectant fungicide, Electis (zoxium and mancozeb) in any blight control programme.

“Electis helps to increase yields and profits, by the effective prevention of leaf, stem and tuber blight,” said Andy Leader, potato specialist for the company. “In trials it has shown to contribute to equal or better yields than many other existing blight products and programmes.”

In a 2006 BPC/SAC trial, an Electis based programme resulted in the top yield, Dow reported. The 11 spray programme with a seven day interval consisting of one Dithane (mancozeb) spray, two Epok (fluazinam + metalayxl-m), one Curzate (cymoxanil + mancozeb), two Electis (zoxium + mancozeb), two Ranman (cyazofamid), a further Electis and two Infinito (fluopicolide + propamocarb) sprays gave a final blight-free yield of 42.32 tonnes per hectare. “Compare this to the woeful 13.4 tonnes/hectare in the untreated and you realise how important it is to maintain a strong programme throughout the crops’ life,” argued Leader.

Looking at other approaches, in the same trials a programme of three Tattoo (propamocarb + mancozeb) followed by seven Shirlan (fluazinam) sprays gave 31.66 t/ha and a programme of three Tattoo followed by seven Valbon (benthiavalicarb + mancozeb) with Zinzan resulted in 32.32 t/ha.

Leader pointed out that the Electis-based programme gave over 10 tonnes per hectare more than these other two programmes. “With potatoes at an average price of £160/tonne, this makes a significant difference in the level of returns.”

“The average cost of a potato blight programme which includes top class foliar and tuber blight protection is around £150/ha, a cost incidentally that has remained broadly similar for at least the past three years. This is equivalent to about 2% of the crop’s value, (assuming a 42 t/ha crop at £160/tonne). The risk of inadequate blight control in potatoes is too high a risk to take, especially in crops destined for pre-pack or baking markets. Growers need to make sure that they use a robust and effective blight control programme throughout the life of the crop,” added Leader.

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