Question

Spotting   QUESTION: Dr. Vann, Today we noticed light whitish-tan colored spots on the leaves of virtually every plant (even the weeds) in our garden. We don't know if it is a problem with a particular deficiency in the soil, too much fertilizer or disease.

ANSWER: Brandon:
Since there are lots of apparently unrelated plants with the same symptoms, I would not be suspicious of an infectious plant disease nor an insect. Based on this information and your photo showing the distribution of the spots, I would be inclined to think along the lines of a contact type injury. Take a look at any chemicals that may have been sprayed in the vicinity previously over the past week or two. There may have been something a weed killer (herbicide) or other injurious material applied close by and on a windy day. Sometimes these materials can get moved around on a breeze. Depending on the dose, I suspect plants will probably recover.
Regards
Steve



---------- FOLLOW-UP ----------

QUESTION: That sounds very probable. We are surrounded by fields so it is likely that some sort of over-spray could have occurred. Is it possible that this type of coloration would be caused by contact with a fertilizer directly on the leaf?

Answer
Brandon:
Yes, it is possible, especially if it was mixed inappropriately and resulted in injury. Sometimes contaminated spray bottles/tanks can be an issue too. Sometimes we may use a sprayer for weed killers and then use it for other things. There may be some residual chemical left in spray tank that causes injury- this is why it is best to not use other products in the same spray container as weed killers are used for.

If you have the opportunity, take a look at those plants in the surrounding fields for similiar spots that may have occurred.

Steve