Foliar Sulfur sprays applied in June and July have been shown to provide several benefits for pecan production, including suppression of mite populations and an increase in nut size. Sulfur may also aid in the suppression of some minor foliar diseases, and there is some evidence that it may aid in scab suppression on cultivars with moderate scab resistance. However, our studies have shown no difference in scab incidence or severity by foliar sulfur on scab susceptible cultivars like Desirable. The research paper discussing foliar Sulfur sprays on pecan can be found here:
While foliar sulfur sprays have proven benefits, growers should be wary of applying Sulfur as a foliar spray when temperatures are in the 95-100 degree range or higher as we are facing over the next week.
The most proven benefits of foliar Sulfur are mite suppression and an increase in nut size. Mite populations are normally higher late in the season and the benefits of Sulfur on nut size can be realized with sprays anytime during the nut sizing period which extends until mid August. Therefore, growers should not feel pressured to get Sulfur sprays out now. Under our current high temperatures, Sulfur may cause more damage in the form of burned foliage than any potential benefits it may provide.