Improving knowledge and experience of micronutrient management in cucurbit production in Wales

Cucurbits include a number of important crops such as courgette, marrow, pumpkin and squash. These crops are robust and can be grown in a variety of field conditions, and can offer increased variety to farm shop style businesses. As field crops, they can also be integrated into a mixed cropping system, or offer an accessible diversification crop for arable farms. Pumpkins can potentially offer high-value returns from pick your own local Halloween markets, however there has been continued growth of pumpkin as an edible crop with a number of prominent eating varieties now available to growers.

A common problem within this crop group is the development of rots such as blossom end rot (BER) which can render the fruit unmarketable. BER can lead to significant crop loses and it is one of the primary sources of wastage in this sector. A limited range of fungal plant protection products are available, but as these are generic fungicides their use in an open field setting may be unsuitable.

An evolving body of evidence suggests that the development of BER is likely to be linked with crop nutritional status and it is believed that management of the crop’s calcium and boron nutritional status may provide a method of its control. As it is a difficult and relatively slow process to control the crop’s nutrition through the soil, applying calcium and boron directly to the plant through foliar feeding may be a more effective method. In this approach, nutrients are applied to the leaf and fruit of the plant as a fine mist which is then absorbed by the plant.

Two relatively small scale horticultural units based in Brecon, who are members of the Tyfu Cymru network, worked together in this two year project to gain more knowledge on whether foliar feeding calcium and boron can reduce the incidence of BER in their pumpkin crops.

Project Objectives

• To gain experience of commercially available foliar feed products, with technical evidence for best practice use guidance for a range of products.
• To develop an evidence base to guide the decision-making process for foliar feeding, using commercially-relevant data to identify the positive effects that can be achieved by foliar feeding.
• To produce a holistic review of nutrition management in cucurbit production to reduce the incidence and severity of BER, reducing wastage and requirement for fungicide application in commercial production in Wales.

Project Results

• The variable onset of BER symptoms, and difficulties achieving effective inoculation in the lab, impacted the ability of this project to draw clear conclusions.
• The results suggest that the use of calcium foliar feeds can be beneficial in reducing the incidence of rots in the field, and the progression of rots once they become established.
• Growers should not assume that all foliar calcium products are equivalent to each other, and they should base their choice of feed product on all available information rather than on pure calcium content alone.
• Foliar nutrient sprays are effective at directly addressing specific deficiencies with the crop but remain secondary in effect to soil nutrient management.