Herbicide injury caused from natural oils and acids including acetic acid (vinegar), clove oil, d-limonene, long-chain fatty acids, and others.
- Leaf burn. Amount of necrosis will depend on how much spray solution contacts the plant. Direct exposure will result in overall necrosis. Small amounts of spray drift may result in leaf spotting.
- Necrotic spots on fruit when spray drift occurs while plants are forming fruit.
- New, untreated growth will look normal.
Naturally occurring oils or acids can be absorbed by any tender tissue resulting in foliar burn to any plant parts if sprayed at high doses or at times of high heat/drought. Young or older treated foliage will show the same symptomology and at the same time intervals with the exception of tissues with thick cuticles, which may not display any symptoms.
Injury from natural oils and acids injury may be confused with symptoms from:
- Other non-selective, postemergence herbicides including glufosinate, paraquat or diquat.
- Protoporphyrinogen oxidase (PPO) inhibitors including acifluorfen, lactofen, sulfentrazne, oxyflourfen, and others.
- Organic arsenical herbicides (MSMA, DSMA) causing desiccation within 1-2 days.
- Salt stress.
- Prolonged drought stress.
Applied Weed Science: Including the Ecology and Management of Invasive Plants (3rd Edition), Merrill Ross & Carol Lembi, pages 165, 170-172.
Publication date: Sept. 10, 2015
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