Too much rain, a 10 degree below zero evening back in December, a sneaky insect pest, a plant disease infecting the tomatoes: solving plant problems is akin to one of those crime scene investigative shows. So many potential culprits, yet the good guys finally identify the real villain. This article provides a current overview of plant issues challenging Owen County farmers, gardeners and homeowners.

The first step in solving the plant crime is looking for evidence. Taking a representative sample in a timely manner is crucial. The next step is to determine if the problem is caused by a living organism (biotic) or a nonliving causal factor (abiotic). For example, purple corn is showing up in the area and sometimes makes growers think a plant problem is being caused by a chemical. What is happening now is due to cool, wet weather and the lack of uptake of phosphorus. Not from a low soil test level, but because environmental conditions have limited the corn plants uptake of P.

Other abiotic factors we are seeing in the area include soil compaction, poor rooting due to wet planting conditions and winter injury of landscape plants (boxwoods took a beating with the cold snap of December 2022 and December 2023). Knock Out roses look ragged now because of the cold winter injury, just that one negative 10-degree day in 2022 killed all my lovely Knock Out roses. Herbicide drift is another potential abiotic causal factor that requires careful investigation by the state chemist’s office.

Once we rule out an abiotic factor, then we evaluate possible biotic factors. The big player in biotic factors are fungal diseases like fusarium, blight and rust. About 85 percent of biotic factors are caused by fungus. Insect damage is always a challenge because so much of their damage is caused when we are asleep. Insects either chew on a plant or suck the sap. Cabbage riddled with chewing holes is often caused by the cabbage looper, the larval stage of the white moth hovering around your brassicas.

Once we identify the real villain, we can prosecute with an appropriate punishment. Sometimes we have no real treatment to recommend, like the dead boxwood. Other instances may warrant a pest control treatment and suggested label recommendations. We don’t recommend home remedies that are not research based. Moles are not repelled by chewing gum, so I never recommend it. I did have a client tell me that it did if Wrigley’s gum was used. Again, no research, no recommendation.

The summer is young and plant problems will keep coming until frost. Contact me at the Purdue Extension-Owen County office at 812-829-5020.

Or, contact me via cell phone at 812-236-6039. My email address is luzar@purdue.edu. You can attach photos to either cell or email messages. If the problem is more challenging, we can arrange a site visit. Challenging issues may require submitting a sample to the Purdue Plant and Pest Diagnostic Lab for $11. I understand that some inquiries will not justify $11, so I will do my best to make identification. But an economically important crop with look-alike disease symptoms should certainly warrant the fee. I have to go now… I just received a photo of a weed called black medic!

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