In field experiments, thresholds, spray timings, and bollworm oviposition were conducted to evaluate the current recommended action thresholds for bollworm (Lepidoptera: Noctuidae) in cotton. Based on studies conducted evaluating thresholds, insecticide applications varied across Bt technologies. Bollgard 3 required less sprays when compared to Bollgard II and non-Bt. A second experiment highlighted the importance of timely insecticide applications for managing bollworm populations in Bollgard II cotton based on insect damage. The highest yields were associated with insecticide applications made during the timeframe that cotton is the most susceptible to bollworm damage. The last experiment was conducted to determine if oviposition varied throughout the plant canopy. Oviposition occurred throughout the whole plant, however, the greatest relationship of egg lay was observed in the top three nodes of the plant. From this research, studies would suggest that the current recommended bollworm thresholds in Mississippi cotton production systems, at this time, do not need to be adjusted.
| Identifer | oai:union.ndltd.org:MSSTATE/oai:scholarsjunction.msstate.edu:td-6107 |
| Date | 30 April 2021 |
| Creators | Francis, Michael Cade |
| Publisher | Scholars Junction |
| Source Sets | Mississippi State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
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