Resource Guide for Organic Insect and Disease ... - Cornell University

Micro Sulf (NuFarm Americas, Inc.)
Microthiol Disperss (United Phosphorus Inc.)
PHT Copper Sulfur Dust (J.R. Simplot Company)
pht Bt 25 Sulfur Dust (Britz-Simplot Grower Solutions LLC)
pht Copper Sulfur 15-25 Dust (Britz-Simplot Grower Solutions LLC)
pht Dryout Dust (Britz-Simplot Grower Solutions LLC)
Proganic Micronized Sulfur (Wilbur-Ellis Company)
ProNatural Micronized Sulfur (Wilbur-Ellis Company)
Safer Brand 3-in-1 Concentrate II (Woodstream Corporation)
Safer Brand 3-in-1 Garden Spray II (Woodstream Corporation)
Special Electric (Wilbur-Ellis Company)
Sulfur DF (Wilbur-Ellis Company)
Wilbur-Ellis Ben-Sul 85 (Wilbur-Ellis Company)
Lime Sulfur
Rex Lime Sulfur Solution (OR-Cal, Inc.)
Tetrasul 4s5 (OR-Cal, Inc.)
References to OMRI listed products in this Guide are based on the 2012 edition of the OMRI
Product List. Please consult www.omri.org for changes and updates in the brand name product
listings.” after product list.
REENTRY INTERVAL (REI) AND PRE-HARVEST INTERVAL
Elemental sulfur REI 24 hours, PHI 0 days
Lime sulfur REI 48 hours, PHI 0 days
AVAILABILITY AND SOURCES
Sulfur and lime sulfur are widely available from agricultural suppliers and through mail order.
EFFECT ON THE ENVIRONMENT
In its elemental reduced or oxidized forms, sulfur represents approximately 1.9% of the total
weight of the earth. Most aquatic and terrestrial environments are high in sulfur (Extoxnet
1995). Sulfur is an essential macronutrient for crop production, and it is allowed by the NOP
as a soil amendment for crop fertility. As mentioned above, sulfur fertility status has been
associated with increased crop resistance to some pathogens. Since the reduction of sulfur air
pollutants, some areas of the world are experiencing soil sulfur deficiencies.
Wildlife
Elemental sulfur is considered non-toxic to birds, aquatic organisms, and honeybees
(Extoxnet 1995). The acidifying effects of sulfur on soil have been reported to cause declines
in earthworm populations. Carcamo et al. (1998) found an absence of earthworms in sulfurcontaminated
soil close to a natural gas processing plant. Earthworms were virtually
eliminated at sulfur levels in the soil of 6673 mg/kg (pH 2.85) at a distance of 50 m from the
source, increasing only slightly as the pH rose to 5.39 at 250 m. Sulfur is used on turf for
decreasing earthworm numbers to manage earthworm castings on golf course fairways. In
one study, applications of ammonium or ferrous sulfate over a two-year period lowered pH
and reduced castings compared with an untreated control (Backman et al. 2001). Sulfur levels
high enough to decrease soil pH are not likely from foliar applications for disease or insect
management, but the pH levels associated with soil applications for scab control in potato are
in the range reported to reduce earthworm populations.
Natural enemies
While elemental sulfur has generally been thought to be detrimental to natural enemies, especially
predaceous mites, an examination of the literature reveals a wide range of impacts. Studies
looking at impacts on predaceous mites have found both strong negative (Prischmann et al.
2005) and negligible (Costello 2007; Stavrinides & Mills 2008) impacts on Galindromus occidentalis,
moderate impacts on Euseius mesembrinus (Childers et al. 2001), and negligible impacts
on Typhlodromus pyri (Zacharda & Hluchy 1991) and Anystis baccarum (Laurin & Bostanian 2007).
Organic Resource Guide 175