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Back in June, we injected a year’s worth of imidacloprid through the irrigation system in an attempt to achieve systemic control of leafminers and psyllids.  Immediately following the treatment — within a week or so — there was a flush, and it was hammered by leafminers.  We applied a spray application to try and control them, but that of course has limited success when they’re already bad and doesn’t really control anything on subsequent flushes.

Our neighbor on Okeechobee Road, David Robinson, has been working with Dr. Steve Lapointe with USDA on the use of leafminer pheromone that causes mating disruption.  It’s applied in a compound called “Splat” (aptly named in our opinion), and David has built a machine that applied gobs of it on leaves in carefully controlled amounts to evaluate dosage and longevity.  David had a little left over from a recent field application, so he kindly ran over to Rock Bottom and applied a good dose.

The next flush that emerged came out clean.  No leafminer or psyllid damage.  It’s hard to say at this point whether it was the imidacloprid, Splat, or both that had an effect.  I suspect the Splat played a role since we don’t see leafminer in the microjet block, which received an imidacloprid trunk drench instead of an irrigation injection, and usually that has limited success on trees the size of those in Rock Bottom.

We are very interested in using tools such as these to reduce the amount of foliar sprays necessary to grow grapefruit.  Between canker and psyllid control for greening, if we applied a spray every time it appears necessary, the number of applications would be excessive and there wouldn’t be any hope of biological control.  We feel that the imidacloprid injection, because of the root balls and extremely efficient uptake, is a promising tool, and the Splat technology is exciting.

Rock Bottom is being hammered by both canker and HLB.  Our less aggressive program to date has not worked well, so for the moment we would recommend the heavy spray program on commercial acreages.  But, we’re not done yet, and hopefully will find the balance we would need to rely less on spraying and more on less expensive and disruptive measures.