Within-plant distribution patterns of the cotton fleahopper (Hemiptera: Miridae)

Authors: Suh, Charles; Westbrook, John

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 5/1/2009
Publication Date: 5/1/2009
Citation: Suh, C.P., Westbrook, J.K. 2009. Within-plant distribution patterns of the cotton fleahopper (Hemiptera: Miridae). pp. 708-711. National Cotton Council Beltwide Cotton Conference.

Interpretive Summary: The standard method for quantifying cotton fleahopper abundance in cotton fields involves whole plant examinations and direct counts of fleahoppers on plants. This sampling procedure, however, becomes increasingly laborious and time-consuming as plants increase in size. We examined the distribution of cotton fleahopper adults and nymphs on cotton plants to determine whether sampling only the terminal portion of plants provides reliable fleahopper population estimates. Overall, we found that the terminal portion of plants accounted for 65 percent of the adults and 78 percent of the nymphs observed on plants. Our findings suggest fleahopper population estimates obtained from sampling only the terminal portion of plants are adequate for pest management programs, but this sampling practice does not provide the level of precision typically required in population research.

Technical Abstract: The standard method for estimating cotton fleahopper abundance involves whole-plant examinations and direct counts of fleahoppers on plants. This procedure, however, becomes increasingly arduous and time-consuming as plants increase in size. We examined the distribution of cotton fleahopper adults and nymphs on plants to determine whether sampling only the terminal portion of plants provides reliable population estimates. Fleahopper distribution patterns were examined in seven commercial fields during the initial three or four weeks of squaring in 2007 and 2008. Examinations were performed three days a week and twice each day (0800-1130 h, 1300-1630 h) to reveal potential time-of-day sampling effects. Overall, the mean numbers of fleahoppers observed during the morning and afternoon sampling periods were statistically similar. However, significantly more adults and nymphs were observed in the terminal of plants than below the terminal during both sampling periods. When the total numbers of fleahoppers (adults and nymphs combined) observed on plants were regressed on the numbers of fleahoppers found in the terminal of those plants, the relative variation and R2 values of the model were 28 and 0.89, respectively. Based on the slope of the regression, the terminal accounted for 75% of all fleahoppers observed on plants. Our results suggest fleahopper population estimates obtained from sampling only the terminal portion of plants are adequate for pest management programs, but this sampling practice does not provide the level of precision typically required in population research.