Tarnished Plant Bug (Hemiptera: Miridae) Thresholds and Sampling Comparisons for Flowering Cotton in the Midsouthern United States

Abstract

The tarnished plant bug, Lygus lineolaris (Palisot de Beauvois) (Hemiptera: Miridae), has become the primary target of foliar insecticides in cotton, Gossypium hirsutum L., throughout the Midsouth over the past several years. This prompted a reevaluation of existing action thresholds for flowering cotton under current production practices and economics. A trial was conducted at 19 locations throughout the Midsouth during 2006 and 2007. Threshold treatments ranged from a weekly automatic insecticide application to a very high threshold of 10 tarnished plant bugs per 1.5 row-m on a black drop cloth. Individually, all locations reached the lowest threshold, and eight locations had a significant yield loss from tarnished plant bugs. Across all locations, lint yield decreased 0.85 to 1.72% for each threshold increase of one tarnished plant bug per 1.5 row-m. Yield loss was most closely correlated to pest density during the latter half of the flowering period. The relationship between plant bug density or damage and yield was similar for drop cloth, sweep net, and dirty square sampling methods, but the correlations among these sampling methods were not high. Incorporating actual insecticide application data from the trial and average production and economic factors for Midsouth cotton, the economic threshold, if monitoring once per week, should be between 1.6 and 2.6 tarnished plant bugs per 1.5 row-m during the flowering period. More frequent monitoring or situations where insecticide applications are more efficacious may alter this threshold.

Development of a Plant-Based Threshold for Tarnished Plant Bug (Hemiptera: Miridae) in Cotton

“…Although the 5% dirty squares threshold resulted in a greater economic return in the Mississippi and Arkansas experiments, previous research has shown that lower thresholds with a drop cloth do not provide additional returns for the additional insecticide applications (Musser et al 2009a). The 10% dirty squares threshold resulted in similar numbers of applications, yields, and economic returns to that with a drop cloth in the Mississippi and Arkansas experiments, and also produced the highest economic return in the Louisiana experiment.…”

“…The numbers of adults and nymphs were counted and recorded. The threshold used for drop cloth samples was three tarnished plant bugs per 1.5 row/m (Musser et al 2009a). The decision to make an insecticide application was based on the average of all four replications for each threshold.…”

“…During the ßowering stages, thresholds are based on drop cloth samples, but no consideration is given for a plant-based threshold like that of square retention during the preßowering stages. The threshold for tarnished plant bug during the ßowering stages is three bugs per 1.5 m of row (Musser et al 2009a).…”

Tarnished Plant Bug (Hemiptera: Miridae) Thresholds for Cotton Before Bloom in the Midsouth of the United States

“…This paper focuses on yield response to tarnished plant bug feeding before bloom. The impact of tarnished plant bug feeding during the ßowering period is addressed elsewhere (Musser et al 2009). …”

Impact of Planting Date and Varietal Maturity on Tarnished Plant Bug (Hemiptera: Miridae) in Cotton

“…A sample involved laying the drop cloth between two rows and shaking all of the plants from each row within the 0.76 m onto the drop cloth. Previous research determined that the drop cloth is the most effective sampling method to determine tarnished plant bug population levels during the ßowering period, because populations at this time are made up mostly of nymphs (Musser et al 2007(Musser et al , 2009a. Nodes above white ßower were determined by counting the number of main stem nodes above the uppermost Þrst position white ßower as described in Bourland et al (1992).…”