Bill Cissel, Extension Agent – Integrated Pest Management; bcissel@udel.edu
Over the past couple of weeks, we have been following the corn plant in the photographs below to see if the plant would out-compete the slugs or if the slugs would ultimately kill the plant.
In the first photo taken on May 9th, I asked, if all your plants looked like the the plant in the photograph, would you apply slug bait? Sixty percent of the respondents said they would and forty percent said No.
Taken on May 9th, 2018
Approximately one week later, I took another photograph of the same plant and asked, if you said YES, that you would treat the field if all the plants looked like the plant in the first photo taken on May 9, do you think you made the right decision. Half (50%) of the respondents said that they feel they made the right decision in treating and half said they didn’t feel as though they made the right decision to treat.
As I mentioned last week, this is a difficult decision and in many cases, there is no “right or wrong”. That is because the weather is a variable that can’t be controlled for and is often not easy to predict, or should I say, rarely predicted accurately. There is little doubt that the plant in the pictures would be in serious trouble now if the weather had been cool and wet.
Taken on May 15, 2018
Below is a photo of the same plant we have been following taken on May 24, 2018. As you can see in the photo, the plant is well on its way and with some sun and heat; I expect it to jump, leaving slugs in its rear view mirror. However, even though this plant is well on its way, there are spots in this field that the slugs are doing their best to kill the plants. There is little doubt that if the weather conditions had been less favorable for corn growth during the past few weeks, this field would be in a re-plant situation today.
Taken on May 24, 2018
Determining when an application of slug bait is justified can be difficult and only comes with experience because the weather has so much impact on not only seedling vigor and growth but also the slugs. There really isn’t a “right” or “wrong” answer in this scenario because even though everything suggests that the plant in the photo will survive and out compete the slugs, there is still some uncertainty as to whether or not the slug feeding injury has impacted the yield potential of this plant.
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