<i>Diatraea saccharalis</i> (F.) and <i>Eoreuma loftini</i> (Dyar) are stem boring pests of sugarcane (<i>Saccharum</i> spp.) and rice (<i>Oryza sativa</i> L.) crops in the Gulf Coast region. Studies were conducted to determine the role of agroecological factors, including predator disruptions, alternate hosts, and crop phenological conditions, on stem borer populations.<br>
The year after Hurricane Rita storm surge flooded sugarcane in Louisiana, a 71% reduction in the predaceous <i>Solenopsis invicta</i> Buren was recorded. Even with a 2.4-fold increase in the number of insecticide applications used for <i>D. saccharalis</i> management in flooded fields, growers still incurred higher injury.<br>
In two field experiments, October sampling showed that sugarcane planted in early August harbored 4.7 to 19.0-fold greater <i>D. saccharalis</i> infestations than September plantings. Although there is a potential for increased <i>D. saccharalis</i> overwintering populations in early plantings, differences in infestations were not recorded during the spring.<br>
Sentinel plant experiments confirmed that a number of non-crop grasses are stem borer hosts. Subsequently, sampling along transects every 6-8 wk compared stem borer infestations in non-crop grasses adjacent to rice fields. While <i>D. saccharalis</i> densities were relatively low, <i>E. loftini</i> average densities were 0.3 to 5.7 immatures/m2 throughout a 2-yr period. A greenhouse study showed that rice is more preferred for <i>E. loftini</i> oviposition than the primary non-crop hosts johnsongrass [<i>Sorghum halepense</i> (L.) Pers.] and Vaseys grass (<i>Paspalum urvillei</i> Steud.). In addition, <i>E. loftini</i> larval development duration in degree-days above a threshold temperature is 1.7-fold greater on johnsongrass and Vaseys grass than on rice.<br>
A 2-yr rice study showed that a lower than traditional harvest cutting height (20 vs. 40 cm) reduced <i>E. loftini</i> infestations by 70 to 81% whereas <i>D. saccharalis</i> infestations were not changed. Furthermore, rice stubble under favorable conditions represents an overwintering habitat in addition to non-crop hosts.<br>
This research showed that predator disruptions, sugarcane planting dates, non-crop hosts, and rice stubble management impact stem borer populations when they are traditionally left unmanaged. Thus, the evaluation of a stem borer management strategy that targets infestations in late season sugarcane and rice, but also in non-crop hosts, is warranted.
| Identifer | oai:union.ndltd.org:LSU/oai:etd.lsu.edu:etd-06272011-125731 |
| Date | 29 June 2011 |
| Creators | Beuzelin, Julien M. |
| Contributors | Damann, Kenneth E., Jr., Webster, Eric P., Stout, Michael J., Wilson, Lloyd T., Blouin, David C., Reagan, Thomas E. |
| Publisher | LSU |
| Source Sets | Louisiana State University |
| Language | English |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | http://etd.lsu.edu/docs/available/etd-06272011-125731/ |
| Rights | unrestricted, I hereby certify that, if appropriate, I have obtained and attached herein a written permission statement from the owner(s) of each third party copyrighted matter to be included in my thesis, dissertation, or project report, allowing distribution as specified below. I certify that the version I submitted is the same as that approved by my advisory committee. I hereby grant to LSU or its agents the non-exclusive license to archive and make accessible, under the conditions specified below and in appropriate University policies, my thesis, dissertation, or project report in whole or in part in all forms of media, now or hereafter known. I retain all other ownership rights to the copyright of the thesis, dissertation or project report. I also retain the right to use in future works (such as articles or books) all or part of this thesis, dissertation, or project report. |
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