Field Conidial Spray Inoculation
Protocol modified from Dr. Ruth Dill-Macky’s original.
Sprayer: Double nozzle solo backpack
Sprayer Capacity: 8 liters
Inoculum concentration: 100,000 macroconidia/liter
Isolates/tank mix: Use as many isolates as on hand
Surfactant: Tween-20
Storage of isolates. We store FHB inoculum (macroconidial suspensions) frozen in a concentrated form (800,000 macrocondia/ml) in one-liter Nalgene bottles.
A. Thawing of Inoculum
1. Thaw inoculum on the day of inoculation. Thaw in cool water in the sink until a small sliver of ice remains in each of inoculum bottles.
Please calculate how much inoculum is needed to spray the plots intended before pulling inoculum from the freezer.
2. Hold thawed inoculum on ice in coolers to take to the field.
Any unused inoculum should be discarded at the end of the day.
B. Diluting Inoculum in the Field
NOTES:
- Appropriate eye protection and protective clothing should be worn whenever operating spray equipment.
- Inoculum should be applied towards the end of the day to minimize detrimental UV effects.
3. Transfer one liter (a bottle) of concentrated inoculum (800,000 macroconidia/ml) into the main tank of the sprayer
4. Add 20 ml of Tween-20
5. Add 7 more liters of water (Total volume = 8 liters/tank)
6. Replace the lid on the spray tank and lock the lid in place
7. Check the lid is aligned and you have a good seal
8. Shake the tank to mix well
9. To spray, pump the handle to create pressure.
C. Inoculation of Plots
14. Inoculate plots at a rate of 1 second/linear foot of row. Time the application using a stop-watch.
(A ten foot row would be inoculated for 10 seconds or an 8 foot row would be inoculated for 8 seconds). Be sure to keep an even rate of movement and spray inoculum over the row in two to three passes of the sprayer-wand.
When the tank is empty, note or mark the plot number you are stopped at and refill the spray-tank.
Kent Evans, RDM lab Page 2 of 2 modified by NMundell: 2/1/2007
C:\Scab data\Protocols\Current\Conidial Spray Inoculation.doc