I get requests each year to provide an example of a fungicide program for pecans. DMI/Stobilurin mixes include Absolute, Brixen, Custodia, Quilt, Top Gard EQ, and Amistar Top (used to be called Quadris Top). Use Amistar Top only during extreme pressure. You could also make your own DMI/Strobi mix, sometimes cheaper than you can buy a pre-mixed product. Just be certain you have the correct amount of active ingredients in the mix. Check with our pathologists or your chemical dealer for options. There is no one program suited to every grower and every cultivar but the following provides a few options:
8 spray program for moderately susceptible cultivars or those under less scab pressure
1. DMI/Strobi mix
2. Phosphite–2 qt/acre rate*
3. DMI/Strobi mix
4. Elast/Tin
5. DMI/Strobi mix +Phosphite
6. Elast/Tin
7. Elast/Tin
8. Tin
*Check mixing compatibility of your phosphite and foliar zinc (or other foliar nutrient) choices prior to application. Some phosphite and zinc products do not mix well.
Heavy Scab Pressure (Desirable, Pawnee)
1. DMI/Strobi mix
2. Phosphite–-2 qts/acre
3. DMI Fungicide or Strobilurin + Phosphite (2 qts/acre)
4. DMI/Strobi Mix
5. Elast/Tin
6. Elast/Tin
7. Amistar Top
8. Elast/Tin
9. Elast/Tin
10. DMI/Strobi Mix + Phosphite
11. Elast/Tin
12. Elast/Tin
Continue to rotate Elast/Tin and the DMI strobi Mix if you need to go beyond 12 sprays
OFF Crop or Low Scab Risk Cultivar 8 spray Program
1. DMI or Strobi plus Phosphite @ 1 qt/acre
2. Phosphite–2 qt/acre rate*
3. DMI/Strobi mix
4. Tin
5. DMI/Strobi mix
6. Tin
7. DMI + Phosphite @ 2 qt rate
8. Tin
I have heard of a few growers out spraying already. It will make for a long spray season if you have started this soon. Most cultivars will not need spraying at this point. In addition, scab pressure is low with the cool temps we are experiencing and rain has been very scattered. I don’t see a need to get in a big rush to start spraying just yet. At the earliest, you may need to consider getting started next week on some early cultivars that are out far enough by then.
Protect your foliage and any crop that develops but as you make spray decisions consider the potential market that is out there for the crop and make wise decisions based on net return and not on keeping up with what your neighbor is doing.
