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

174 Organic Resource Guide
FORMULATIONS AND APPLICATION GUIDELINES
Formulations of elemental sulfur include dry flowable, water-dispersible granules, soluble
concentrates, and wettable powders. Smaller sulfur particles have been shown to be more toxic
to fungi in numerous trials (summarized in Horsfall 1956) and to better adhere to leaf surfaces
(Feichtmeyer 1949). Finely ground sulfur for dusting is made flowable by the addition of clay,
talc, gypsum, or other materials. Micronized sulfur is ground to especially fine particles (4-5
microns). Colloidal sulfurs are even smaller particles produced by several possible methods,
including acidifying lime sulfur solutions. Flowable sulfur is a microfine sulfur formulated in an
aqueous suspension.
Elemental sulfur may cause phytotoxicity at high temperatures; it should not be used if
temperatures are forecasted to be above 90° F within three days following application. It
should not be applied within two weeks of an oil application. It may cause toxicity in sensitive
plants, including some varieties of grapes; apples and pears; cranberries; apricots; certain
varieties of cucurbits, particularly melons; filberts; and spinach. Test a few plants of each
cultivar in sensitive families before applying sulfur to the entire crop.
Sulfur dust suspended in air ignites easily. Keep away from heat, sparks, and flame. Do not
smoke while applying.
Elemental sulfur is also formulated with other pest management materials, namely Bt (Bacillus
thuringiensis) and fixed coppers. These formulations have generally not been tested in
university trials and are not included in the efficacy information supplied below.
Lime sulfur is a liquid. It has a strong potential for phytotoxicity. It is used as a dormant
application to fruit trees to control fungal and bacterial pathogens, mites, and scale insects.
During the growing season, it is also used at lower rates to control several fungal pathogens.
It can be used as a spray crop thinner in apples during and shortly after bloom, usually in
conjunction with oil. With this usage, lime sulfur’s phytotoxic effect reduces photosynthesis
and stresses the trees, resulting in the abscission of some fruitlets (Schupp et al. 2006).
CROPS AND VARIETIES THAT MAY BE INJURED BY SULFUR
D’Anjou pears
Comice pears
MacIntosh apple
Jonathan apple
Golden Delicious apple
Concord grape and some other labrusca varieties
cranberries
apricots
certain varieties of cucurbits, particularly melons
certain varieties of beans
filberts
spinach
OMRI LISTED PRODUCTS
Elemental Sulfur
BT 320 Sulfur 25 Dust (Wilbur-Ellis Company)
Cosavet DF (Sulfur Mills, Ltd)
CSC Copper Sulfur Dust Fungicide (Martin Operating Partnerships, LP)
CSC Dusting Sulfur (Martin Operating Partnerships, LP)
Dusting sulfur (Wilbur-Ellis Company)
Dusting Sulfur Fungicide-Insecticide (Loveland Products, Inc.)
Golden Micronized Sulfur (Wilbur-Ellis Company)
IAP Dusting Sulfur (Independent Agribusiness Professionals)
Integro Magnetic Sulfur Dust (Integro, Inc.)
Kumulus DF (Arysta LifeScience North America Corporation and BASF Sparks, LLC)