Which parameters are used in forecasting fire blight?

The correct choice highlights the significance of temperature, relative humidity, and precipitation in forecasting fire blight, a bacterial disease primarily affecting fruit trees, particularly apples and pears.

Temperature is a critical factor since the pathogen responsible for fire blight, Erwinia amylovora, has specific temperature ranges that favor its growth and activity. Warmer temperatures often promote bacterial multiplication and increase the likelihood of infection.

Relative humidity plays a pivotal role in the moisture availability necessary for bacterial dissemination and infection. High humidity levels can create conditions conducive for the pathogen's survival and increase the chances of infection through flower wounds or other entry points in the plant.

Precipitation is also a significant parameter since rainfall can facilitate the spread of the bacteria to plant surfaces and canopy, often washing pathogens down from infected plant parts, which can lead to new infections.

This combination of environmental conditions—temperature, humidity, and precipitation—creates an optimal environment for the development and spread of fire blight, making it essential for accurate forecasting and subsequent management practices.