The perfect day -- warm weather, and not a cloud in the sky!

Becky Yates, Arapaho’s Irrigation Manager, and I spent the day working out imidacloprid injection in the drip zones at Rock Bottom.  It was a classic “Bluebird Day”, without a cloud in the sky — perfect weather.

Typically, trees 3 years old and up are too large for imidacloprid to work — it’s too diluted in the tissue to control asian citrus psyllids and leafminers.  The South African growers have had success with injecting imidacloprid, so we decided to give it a try with a Florida twist.

The theory is to apply an entire year’s worth of imidacloprid all at once to try and build the level high enough to control psyllids and leafminers on the critical summer flushes that normally get hammered hard.  We planned it out, and then waited for the right moment.

To promote maximum uptake of the imidacloprid, we waited for two days in a row with clear skies and warm temperatures.  These conditions cause the stomates in the leaves to open to the maximum extent, resulting in the highest transpiration rates, and water uptake by the root systems, of the year. June is the month when this is most likely to occur, plus it’s just before the rainy season when the flushes kick off.

Yesterday, we turned off the irrigation in the drip zones.  The root clusters under the drip emitters are incredibly dense right now, and if you turn off the water for even one day, the roots dry out the soil in those clustered areas rapidly, even if the surrounding soil is wet. 

Today, we injected the imidacloprid in 20-minute cycles, followed by 20 minutes of irrigation to get all the material out of the system.  We have been applying six 30-minute pulses each day, so this is much less water than the trees have been receiving on a daily basis, but enough to carry the material down through the root zone, made easier because the roots are clustered right at the soil surface.

We’ll withhold irrigation tomorrow and Sunday.  Usually only one day afterwards should be sufficient, but we’re giving Becky a day off, and want to provide this first attempt the best chance.  The root clusters should suck up every drop of the water we applied today, which will pump as much imidacloprid into the trees as possible within 48 hours.

We are hoping to achieve psyllid control even with relatively large trees.  For comparison, we applied the same amount of material to the trees in the microjet zone as a trunk drench last week.

We’ll keep you posted.

Pete