Cucurbits and their challenges
Cucurbits play an essential role in agriculture worldwide, contributing to the economy due to their cultivation in both small-scale and commercial farming. The adaptability of cucurbits to different climatic and growing conditions further enhances their importance, contributing to global food security and economic stability in the agricultural sector. The production of cucurbits is, however, not without challenges, with numerous diseases responsible for the considerable decline in the growth and yield of these crops.
Powdery mildew is a prevalent fungal disease that affects many different crops, leading to substantial yield and economic losses. This disease is caused by various fungal species such as Podosphaera xanthii and Erysiphe cichoracearum, and is characterized by the appearance of white, powdery spots on the leaves, stems, and fruit of affected plants. As the disease progresses, it weakens the plant by reducing photosynthesis, stunting growth, leading to premature leaf drop, and shortening the ripening and harvesting periods (Zhang et al., 2021). This, in turn, decreases the quality and yield of the crop.
The application of fungicides is often the reliable solution that growers turn to as a control measure against fungal diseases such as powdery mildew.
The use of copper as a fungicide
While copper (Cu) compounds have revolutionized crop protection, their continuous and frequent use has also raised concerns about the long-term sustainability of crop protection. This is due to the impact of Cu-based compounds that may affect factors such as soil fertility and groundwater due to their intensive use, leading to Cu-accumulation over time (Lamichhane et al., 2018). Furthermore, the application of these products, such as copper sulphate and copper nitrate, or spraying highly acidic solutions (pH below 5.5), can result in phytotoxicity (Behlau et al. 2017). Due to the many constraints of different Cu-based formulations, the use of less soluble types of Cu, such as copper hydroxide and copper oxychloride, is encouraged.
COPRWET™’s Cure for Cucurbit Conundrums
COPRWET™ is a suspension concentrate, contact fungicide containing 300g/L copper oxychloride (CuOCl) as the active ingredient.
Copper oxychloride slowly releases copper ions, which are toxic to fungi and bacteria. The copper ions disrupt essential cellular processes in pathogens, inhibiting spore germination and fungal growth.
What makes COPRWET™ a significant fungicide?
- Contains 40-60% less copper than alternative copper products but still delivers the same efficacy.
- Stable and flowable formulation.
- Contains OROWET®TECH within the formulation – no additional adjuvant necessary.
- The added benefit of containing OROWET®TECH includes:
- An optimal protective film
- Optimal adherence to plant surfaces
- Excellent coverage
- A reservoir of copper ions
- Controlled release of copper ions over time
COPRWET™ acts on the surface of plants, preventing infection rather than curing an existing disease.
Over three different trials targeting the control of powdery mildew on baby marrows, COPRWET™ demonstrated significant control compared to an industry standard commonly used in prevention programmes (Figure 2).
The results show that on both the adaxial (top) and abaxial (bottom) sides of the leaves, COPRWET™ effectively controlled the spread of powdery mildew, thereby highlighting the excellence of this flowable formulation that ensures optimal coverage and adherence to the entire plant surface.
From these results and based on the discussion regarding the use of Cu-based fungicides and their position in long-term crop protection, it is clear that effective management strategies, such as applying a copper-based fungicide that contains less actual copper but still provides optimal protection, can be a game-changer in the control of powdery mildew on cucurbits.
References:
Behlau F., Scandelai L.H.M., da Silva Junior G.J. & Lanza F.E. 2017. Soluble and insoluble copper formulations and metallic copper rate for control of citrus canker on sweet orange trees. Crop Protection 94:185–191. Available from: https://doi.org/10.1016/j.cropro.2017.01.003
Lamichhane, J.R., Osdaghi, E., Behlau, F., Köhl, J., Jones, J.B. & Aubertot, J.N. 2018. Thirteen decades of antimicrobial copper compounds applied in agriculture. A review. Agronomy for Sustainable Development 38(28). Available from: https://doi.org/10.1007/s13593-018-0503-9
Messelink, G.J., Calvo, F.J., Marín, F. & Janssen, D. 2020. Cucurbits. In: Gullino, M., Albajes, R. & Nicot, P. (eds) Integrated Pest and Disease Management in Greenhouse Crops. Plant Pathology in the 21st Century, Vol 9. Springer, Cham.
Zhang, S., Liu, J., Xu, B. & Zhou, J. 2021. Differential responses of Cucurbita pepo to Podosphaera xanthii reveal the mechanism of powdery mildew disease resistance in pumpkin. Frontiers in Plant Science (12). Available from: https://doi.org/10.3389/fpls.2021.633221
