Comments: I purchased this at a local store to try it out, the plan being to order concentrate from RWH if it worked. Well, it didn't work at all!  My horse suffered despite multiple applications & the flies laughed at me. I'm using (Nature’s Force) the MannaPro brand of Natural Shield in the green bottle… & it's awesome!  Smells great & the flies get aggravated looking for landing pads on my horse. :-))  Organic oils & leaves her coat shiny.  RWH needs to carry this ASAP. It's great stuff!
From: HorseCrazyRN - St. Louis, MO, USA
RW Response: Thank you for your review! Nature's Defense is a water based fly spray, while Manna Pro Natural Shield is an oil-based product. It is difficult to compare the two as oil-based sprays will always last much longer than a water-based spray. We recommend the Ultrashield Green or the EcoSmart Fly Spray as they are both oil-based, natural sprays and will last longer! 

Comments:This fly spray smells pleasant and is easy to apply, but it does not last very long. I put it on a horse after I brushed him and by the time I was done tacking up, the flies were back. I did another application and it seemed to work for a little longer. Not a perfect product, but it works decently. 
From: Casey- Portland, Oregon, USA