Which irrigation method reduces leaf wetness and disease risk?

• A. Overhead irrigation
• B. Drip irrigation
• C. Furrow irrigation
• D. Flood irrigation

Answer: (B)

Leaf wetness duration on leaves drives the risk of foliar diseases. Drip irrigation delivers water directly to the root zone with little to no contact with the foliage, so the leaves stay dry and the surface moisture time is short. That dry leaf surface makes it harder for pathogens that require free water to infect, which lowers disease risk in a greenhouse setting. In contrast, overhead irrigation showers the canopy, wetting leaves and often keeping them moist longer, which creates ideal conditions for foliar infections. Furrow and flood irrigation also tend to wet the soil surface and can cause splash or higher canopy humidity, increasing the likelihood of leaf infections. So, drip irrigation best reduces leaf wetness and disease risk.