Spray Diary: Fourth Spray

Spray Date: May 2, 2017

The scheduled date for this spray was May 5, two weeks after the third spray. High humidity dictated that this date be moved up due to signs of Downy Mildew.

The tank mix was slightly modified from  previous sprays: no pesticide, a mixture of two different brands of Dithane, and granulated Rally.

• Revus Top—30 ml to prevent Black Rot, Downy Mildew and Powdery Mildew.
• Dithane M45—6 oz. dry weight, measured on a small scale. This was actually a mixture of the last of the Southern Ag Dithane and Manzate Pro-Stick. They are chemically the same, but I found a new source where I can get a six-pound pack at a reasonable price.
• Rally—This version of actual Rally is a granulated form that comes in pre-measured 4 oz. packs. I weighed out 2 oz and saved the other half for the next spray.
• Agrifos—Added 240 ml to the tank mix for Downy Mildew. This stuff really works on an active outbreak of Downy.
• Elevate—Added 2 oz. of Elevate 30 WDG. Still trying to determine if the proper dose is 4 oz.

I did not include any pesticide this time. I ordered liquid Carbaryl 4L, a double-strength version of Sevin. It should be here before I spray again.

The vines are growing by leaps and bounds, and I'm considering increasing the amount of spray to 20 gallons. I spray both side of the vines, and nearly ran out of spray on April 20.

I created a spreadsheet that calculates the amount of chemicals in five gallon increments up to 30 gallons of spray, based on the concentrations listed above. I'm pretty happy with the performance of this tank blend, pending confirmation of the Elevate concentration.

As of this writing, there is no sign of any new disease pressure. Perhaps I can now get on a two-week schedule.

Next planned spray date is May 14.