Answer: Although there are rusts that attack glads, these diseases are rare, so I wonder if the discoloration on the foliage and the poorly developed flowers are a sign of thrips and not of rust. Rusts are raised spots, either orange or brownish in color; thrips damage is a rusty colored streak. Check your plants carefully to see which of these descriptions fit. If it's damage from thrips, you can put your glads on a preventative spray schedule beginning next spring. To protect the plants, spray or dust the gladiolus when they reach 6 inches in height and continuing treatment every 7 to 10 days until flowering. Diazinon should be used for control. Other insecticides labeled for thrips, such as Tempo can also be used, but only for plants listed on the label. The active ingredient in Tempo is available in Bayer Advanced Garden Multi-Insect Killer. When using insecticides, mix and apply according to label directions.
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