Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/20/1997
Publication Date: N/A
Interpretive Summary: Population levels of selected pest caterpillars and beneficial insects and spiders in early season cotton were measured by sweeping plants with a net, shaking plants over a cloth, and sampling with a new tractor-mounted sampler. Population levels estimated by these methods were compared. Population estimates by the tractor-mounted sampler were usually strongly related to those provided by one or both of the other methods except when very few insects were present in the field. When few insects were present, the tractor-mounted sampler collected insects more often than the other methods, and usually measured populations with the most precision. The tractor-mounted sampler could be further improved, especially with regard to collection of the young of some predators. Our results show the tractor-mounted sampler is appropriate for sampling insects in early season cotton and may be especially useful in detecting and measuring populations occurring at low levels.
Technical Abstract: Population estimates of selected arthropods in early season cotton, including lepidopterous larvae, spiders, and adult and immature hemipterous and chewing predators, by sweep net, drop cloth, and a new tractor-mounted sampler were compared. Population estimates by the tractor-mounted sampler were compared. Population estimates by the tractor-mounted sampler were usually highly correlated to those provided by one or both of the other methods except for arthropods observed only at very low population levels. The tractor-mounted sampler most frequently detected presence of most arthropods at low population levels, and generally provided lower estimates of relative sample variation than sweep net or drop cloth methods. The need for modifications to the tractor-mounted sampler to improve the efficiency of collection of hemipterous nymphs is suggested. Our results indicate the tractor-mounted sampler provides an adequate means of sampling garthropods in early season cotton and may be particularly useful in monitoring arthropods occurring at low population levels.