Have a question about leaf spotting on osteos. Seems like later in the crop we get spotting (or pitting) on the older leafs of the crop. Sometimes there is some yellowing of the plant as well. Is this caused by a lack of feed or something else?

Hi KG -

When you describe pitting and leaf spotting on the older foliage it makes us think of edema. Whether Osteos are grown outdoors or in greenhouses the nights can be on the cool side while the days warm to the 70's and 80's. When you combine a wide temperature fluctuation between day and night with high moisture availability during the day, during the transpiration process the turgor pressure is too high and cells can actually burst causing the spotting you see. The spots are also usually surrounded by a yellow hallow. We also can't rule out something pathogenic such as bacterial leaf spotting or in an edema situation a secondary botrytis infection can set in on the damaged tissue.

Now when you talk about overall yellowing that could be a different issue. Have you checked root health for any signs of disease? Have you checked pH and EC of the soil? What is your fertility program like?

There are several possibilities here. If you have access to a digital camera and could post some images that may help us better determine the cause for the spotting and yellowing.