Effects of Soil Compaction on Bollworm (Lepidoptera: Noctuidae) Moth Emergence 1

Bollworm, Heliothis zea Boddie, moth emergence was measured from a sandy loam soil after increasing levels of soil compaction. Soil strength as measured by indentation probe resistance in kg/cm 2 was measured at successive depths under each level of compaction and related to the moth emergence pattern. Possible physical damage to pupae and the condition of the pupal chamber by the compaction process was determined by placing individual insects in cylindrical containers of soil, compacting the soil in the containers, and then excavating the pupae. Moth emergence decreased significantly with increasing soil compaction and also showed a definite relationship to the pattern of soil compaction vs. depth. Excavation of pupae from compacted soil indicated that soil compaction, rather than physical damage to the pupae, was the primary cause of reduced moth emergence.