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

Bernard et al (2010) found minor detrimental effects against G. occidentalis and Euseius victoriensis
at a rate of 200 g/100 liters, but a high level of toxicity at 400g/100 liters. In other insect orders,
Martinson et al. (2001) found sulfur to be highly toxic to Anagrus parasitoids of grape leafhopper.
Guven and Goven (2002) found low toxicity to green lacewing (Chrysopa carnea) in the lab.
Given such variable research results, general statements about the impact of sulfur on natural
enemies are not possible. Negative impacts are possible and may depend on the type of natural
enemy and level of exposure. The level of impact on natural enemies may be influenced similar to
the way that efficacy against pest mites is influenced by temperature and relative humidity.
EFFECT ON HUMAN HEALTH
Elemental sulfur is known to be of low toxicity to humans and poses very little, if any, risk to human
and animal health. Short-term studies show that sulfur is of very low acute oral toxicity and
does not irritate the skin; however, it can cause some eye irritation, dermal toxicity (toxicity that
results from absorption through skin), and inhalation hazards. Acute exposure inhalation of large
amounts of the dust may cause catarrhal inflammation of the nasal mucosa, which may lead to
hyperplasia with abundant nasal secretions. Analyses of farm worker injury reports in California
found that sulfur is one of the most common pesticides implicated in injuries (Das et al. 2001,
Reeves et al., 2002). No known risks of oncogenic, teratogenic, or reproductive effects are associated
with the use of sulfur (Extoxnet 1995).
Lime sulfur can be fatal if inhaled, swallowed, or absorbed through the skin. It is extremely caustic
and can cause irreversible eye damage and skin burns. If mixed with an acid, it may give off extremely
toxic and flammable hydrogen sulfide gas (Meister & Sine 2009).
EFFICACY
Diseases
In Figures 1-4, “good control” includes studies that showed statistically significant reductions in
pest levels of more than 75%. “Fair control” includes any non-significant reductions over 50% and
significant reductions between 50 and 75%. “Poor control” includes results with less than 50%
control. The Y-axis refers to number of studies in each efficacy category.
Elemental sulfur is most effective and widely used against powdery mildews (PM) in a variety of
fruit and vegetable crops (Figs. 1 & 2). A review of 30 trials conducted on grapes found 19 result-
Number of Trials
Efficacy of Elemental Sulfur Against Diseases of Fruit Crops
Good control Fair control Poor control
25
20
15
10
5
0
176 Organic Resource Guide
Crop -­‐ Pest
Figure 1. Efficacy of elemental sulfur against diseases of fruit crops.