Keep a close eye on corn and soybean fields for SLUG Damage
Slug damage on 5 leaf corn Slug damage on soybeans
 
Photo courtesy of
www.ipcm.wisc.edu Photo courtesy of www.utextension.utk.edu
A new fact sheet from Ohio State provides good information on slug biology, scouting and management of slugs on field crops http://ohioline.osu.edu/ent-fact/pdf/0020.pdf.
Slugs continue to be the main pest of concern in many fields. Options to reduce damage and allow plants to grow ahead of the damage include the use of Deadline M-Ps or night time applications of 30% liquid nitrogen when plants are dry (the rate used in past years was 20 gallons per acre of 30% N on corn in the spike to one-leaf stage and the mix was cut 50/50 with water to reduce – not eliminate -- plant injury). Also, slugs seem to be most active on the plants between midnight and 3 AM so applications of nitrogen have been most effective when applied between those hours. The best control with the Deadline M-Ps has been observed when applications were made and there was at least one day of sunny weather after an application. In general slugs stop feeding in 2-3 hours even though it may take the slugs 2-3 days to die. Last season, we also had reports of good results in commercial fields where a potash application was needed and slugs were also present in the field. It was probably effective due to its high salt index. Remember that when it comes to slug management all of the available control tactics only reduce the slug activity - buying time to enable the crop to outgrow the problem. Research conducted by Galen Dively from the University of Maryland in 2003 indicated that “populations of five or more slugs around each plant prior to the 3-leaf stage may be economic, especially if injury is heavy, plant growth is slow, and cool, wet conditions prevail. If the weather turns hot and dry, 10 or more slugs per plant may be tolerated if the seedlings reach the 3-leaf stage. Generally, if a heavily infested field reaches the 3-leaf stage without severe seedling mortality, the crop has survived the critical period and should outgrow further slug injury, regardless of the population pressure.”
Information from Joanne Whalen, Extension IPM Specialist
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