Resource Guide for Organic Insect and Disease ... - Cornell University
Resource Guide for Organic Insect and Disease ... - Cornell University
Resource Guide for Organic Insect and Disease ... - Cornell University
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Efficacy of Elemental Sulfur Against <strong>Disease</strong>s of Vegetable Crops <br />
Good control Fair control Poor control <br />
Number of Trials <br />
12 <br />
10 <br />
8 <br />
6 <br />
4 <br />
2 <br />
0 <br />
Crop -‐ Pest <br />
Figure 2. Efficacy of elemental sulfur against diseases of vegetable crops.<br />
Number of Trials <br />
5 <br />
4 <br />
3 <br />
2 <br />
1 <br />
0 <br />
Apple -‐ black/white rot <br />
Efficacy of Lime Sulfur Against <strong>Disease</strong>s of Fruit Crops <br />
Apple -‐ flyspeck <br />
Apple -‐ powdery mildew <br />
Apple -‐ scab <br />
Good control Fair control Poor control <br />
Apple -‐ sooty blotch <br />
Blueberry -‐ mummy berry <br />
Grapes -‐ black rot <br />
Grapes -‐ Phomopsis <br />
Grapes -‐ downy mildew <br />
Crop -‐ Pest <br />
Grapes -‐ powdery mildew <br />
Peach -‐ leaf curl <br />
Figure 3. Efficacy of lime sulfur against diseases of fruit crops.<br />
Peach -‐ Rhizopus rot <br />
Peach -‐ scab <br />
Peach -‐ shothole <br />
Pear -‐ scab <br />
ing in greater than 75% reduction in disease compared with the untreated controls, with 11 of<br />
the trials above 90% control. Eleven of 22 trials conducted in cucurbits <strong>and</strong> 10 of 13 conducted<br />
in lettuce had PM reductions of more than 75%. Powdery mildew control was also good in apple<br />
<strong>and</strong> strawberry. Sulfur was less effective against PM in cherry. A review of 12 apple scab trials<br />
found 4 with control levels above 75%. Three trials with poor results used a rate of only 1 lb. per<br />
acre. Most studies tested higher rates of 3-5 lb. per acre. In most trials, sulfur provided fair to good<br />
control of sooty blotch <strong>and</strong> flyspeck of apple, <strong>and</strong> good control of peach scab <strong>and</strong> white mold in<br />
beans. Elemental sulfur is ineffective against a variety of other plant pathogens, including peach<br />
leaf curl, angular leaf spot in strawberry, <strong>and</strong> bean rust <strong>and</strong> gray mold (Botrytis) in bean. Levels of<br />
Botrytis in strawberry <strong>and</strong> brown rot in peaches were actually increased by sulfur applications in<br />
some trials.<br />
<strong>Organic</strong> <strong>Resource</strong> <strong>Guide</strong> 177
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