Pre- And Post-emergence Strike Of Slugs & Snails On Soybeans
DR. RAUL T. VILLANUEVA
PRINCETON, KENTUCKY
The warmer winter in 2024, along with rains and foggy conditions during several days in March and April, have been conducive to the presence of slugs and snails in commercial and research plots in Western Kentucky. Since the end of March and the first week of April, UK entomologists have been observing slugs in various stages of development, including eggs in soybean and corn fields. The favorable conditions described above might have increased their populations in fields, leading to a reduction of plant stands in several soybean fields; in many cases, entire fields have been consumed.
In soybean fields heavily affected by slugs, plant stands of 2 to 10 plants per 5-ft row are in contrast to normal stands of 20 to 30 plants per 5-ft row (based on average plantings in Kentucky: 5 to 6 seeds per foot-row planted in 20” row width) (Figure 1). Damage observed in fields showed that slugs were feeding on unsprouted seeds and emerging seedlings (Figure 2). Also, observations since the first week of April have shown that eggs were laid in moist soils covered by organic matter from the previous crop (soybeans, corn, or wheat). Figure 3 shows that slugs were well protected under dry brace roots of corn, ovipositing eggs under these structures.
Mollusk Management
There is no rescue treatment for slug damage or thresholds for application of molluscicides. If stands are low, replanting is recommended, and an application of molluscicides may be necessary. On February 27, 2024, we wrote a KPN article (Slugs are Active in February 2024, but Farmers Have Two Registered Molluscicides under Section 24(c) in Kentucky) that discussed the possibility of abundant mollusks during corn and soybean germination periods. This was based on environmental conditions and mentioned two metaldehyde molluscicides that are registered under the Section 24(c) for soybeans and corn in Kentucky: Deadline® M-Ps™ and Slug-Fest®. In addition to these two products, Table 1 shows additional molluscicides that can be used in corn and soybeans for management of slugs or snails. ∆
DR. RAUL T. VILLANUEVA: University of Kentucky