Chinese crop protection manufacturer Shandong Yijia Agrochemical Group has expanded its fungicide portfolio with the launch of Aoshuang, a dual-active formulation designed to improve the management of two of the country's most economically damaging oomycete diseases—downy mildew and potato late blight.
The new product combines 10% metalaxyl-M and 10% cyazofamid, bringing together two fungicides with different modes of action to provide both preventive and curative disease control. The launch reflects the industry's growing emphasis on resistance management and longer-lasting crop protection as disease pressure intensifies under humid production conditions.
According to the company, downy mildew in leafy vegetables and cucurbits, together with potato late blight, continues to inflict significant economic losses across China's vegetable sector. The pathogens thrive under prolonged humidity and moderate temperatures, with zoospores rapidly spreading through rainfall, irrigation water and dew, enabling infections to move across fields within days under favourable conditions.
Shandong Yijia estimates that downy mildew affects between 5 million and 8 million mu of leafy vegetables and cucumbers annually, while potato late blight accounts for 20 million to 30 million mu-times of disease occurrence each year, resulting in direct economic losses estimated at RMB 3–5 billion.
The company said existing disease-control programmes are increasingly challenged by fungicide resistance, limited residual activity and poor rainfastness, forcing growers to spray more frequently. Many currently available products also provide either preventive or curative control rather than both, while some formulations pose phytotoxicity risks during sensitive crop growth stages.
Aoshuang addresses these limitations by combining the systemic activity of metalaxyl-M, which moves within plant tissues to suppress established infections, with the protective action of cyazofamid, which remains on the leaf surface to prevent spore germination and primary infection. The two active ingredients belong to different Fungicide Resistance Action Committee (FRAC) groups, supporting resistance-management strategies through diversified modes of action.
The formulation is produced as a suspo-emulsion incorporating a plant-derived adjuvant system designed to improve leaf coverage, adhesion and rainfastness. According to the company, the product can be used throughout the crop cycle without causing phytotoxicity while maintaining effective protection under challenging weather conditions.
Field demonstrations conducted by Shandong Yijia on Indian lettuce indicated rapid disease suppression, with infection reportedly halted within 24 hours, lesions drying within three days and visible crop recovery beginning after five days of application.
The company recommends applying the fungicide as a 750-fold dilution, with spray intervals adjusted according to crop type and disease pressure. Shorter intervals are advised during periods of persistent rainfall, while applications on potatoes are recommended before extended wet weather to maximise protection during tuber development.
The launch comes as growers increasingly seek integrated disease-management solutions capable of extending fungicide performance, improving resistance management and protecting yields in high-value horticultural crops.
