Blight Doesn’t Wait — Neither Should You

Late last week, I visited two tomato growers — one with several seasons under their belt, and another relatively new to the industry. Both had encountered blight in their crops, but the outcomes were very different.

The experienced grower had identified early signs of blight and, understanding the weather conditions were ideal for disease development, had already taken preventative steps. As a result, the outbreak was small and contained.

In contrast, the newer grower had the correct product on hand — but had delayed treatment. Unfortunately, that delay made all the difference. The speed at which both early and late blight (often referred to as “plant destroyers”) can spread is phenomenal. Once visible symptoms appear, you are already behind. Immediate action is essential.

Key Takeaways for All Growers:

• Be proactive, not reactive. If conditions are conducive to disease — high humidity, cooler nights, leaf wetness — apply protectant fungicides even before symptoms appear.
• Have a blight management plan in place. Know what products you’ll use preventatively and what you’ll switch to curatively if infection occurs.
• Do not delay treatment. Waiting even a day can significantly increase the risk of crop loss.
• Consult your local supplier. They can advise on the most effective preventative and curative products currently available and registered for your crop.

Please e-mail: stefan@grower2grower.co.nz for commercial greenhouse growing advice.