More On Fire Blight

More On Fire Blight

More On Fire Blight. I'm Greg Martin with today's Fruit Grower Report.

The tree fruit season is expected to be at least two weeks early this year and in fact cherry trees are already blooming. Temperatures are expected to be up into the 70's and maybe even 80's over the weekend. The warm temperatures and a possibility of rain in some areas could mean a heightened threat of fire blight for some fruit producers. Tim Smith has spend a great deal of his career studying fire blight.

SMITH: So the temperatures are the key component in the fire blight model. You've got to understand that bacteria multiply in a rate governed by temperature and resources. They live in the moment. Bacteria don't have a memory of how warm it was last night or yesterday or the day before that, they're living from moment to moment and the more moisture and food they have available the faster they can grow at given temperatures.

A model of temperatures has changed over the years and shows some interesting results.

SMITH: It turned out that one day at 88 is enough to build up a colony from a small group large enough to cause infection. One day. If it gets a little bit warmer than 90 degrees, like 98, the growth rate declines and they actually stop growing at about 100 degrees Fahrenheit and at 106 they're actually being destroyed and their colony numbers drop.

Smith says the Decision Aid System can help you by calculating a lot of these numbers.

SMITH: When you get on the DAS system you have a wide range of choices there. Fire blight is one of your choices and you click on that and the first think it will say is what's your situation? So you have a high pressure, medium pressure or low pressure. It's so important to know how much fire blight you have in the vicinity.

That's today's Fruit Grower Report. I'm Greg Martin on the Ag Information Network of the West.

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