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The tarnished plant bug (TPB) is a major pest of cotton throughout the midsouthern region of the United States. Research was conducted during the squaring period from 2006 to 2008 in all 5 states of the Midsouth to evaluate thresholds in the current production environment. These data show that costs associated with TPB are minimized when average TPB density is 8 per 100 sweeps and when average square retention is 90%. Existing thresholds of 8 TPB per 100 sweeps and square retention of 80% are supported by these data and should be retained. More aggressive management resulted in both reduced yield and higher control costs and should be avoided. [ABSTRACT FROM AUTHOR]

An abstract of the article "A MidSouthern Perspective on Hemipteran Pests," by Ralph D. Bagwell, B. R. Leonard, Fred Musser, Angus Catchot, D. R. Cook, Scott D. Stewart, Kelly V. Tindall, Glenn Studebaker, D. Scott Akin and Gus M. Lorenz is presented.

Tarnished plant bug, Lygus lineolaris, has recently become the primary pest of mid-season cotton in the Mid-South. Sampling protocols during this period of development are poorly established, resulting in many insecticide applications being recommended based largely on a consultant's personal experience. An evaluation of 9 sampling methods was conducted on commercial fields throughout the Mid-South during 2005. Results show sweep nets and drop cloths to be much more efficient than other direct sampling methods. Sampling dirty blooms was the most efficient indirect sampling method. Correlations to other sampling methods show whole plant counts and sweep nets have the strongest correlations. Further research is needed to establish which methods are most strongly correlated to yield losses. [ABSTRACT FROM AUTHOR]

Boll weevil traps baited with Grandlure pheromone dispensers and dichlorvos (DDVP) dispensers are integral in the effort to eradicate the boll weevil from the United States and Latin America. The Plato Boll Weevil Trap, previously known as the S & S Boll Weevil Trap, has been in operational use in U.S. Boll Weevil Eradication Programs for four years. The Plato Trap offered 26 design modifications that were key improvements compared to the USDA model as manufactured by Precision Plastics. Between the 2003 and 2004 seasons several additional design changes were integrated into the design of the Plato Trap. These changes improved the strength of the capture cylinder and improved the locking feet of the trap cylinder. All of the changes and improvements result in time and cost efficiency improvements of the trap when in operational use. In 2004, the Plato Boll Weevil trap was compared to a new plastic trap manufactured by Technical Precision Plastics of Mebane, NC. The data illustrated no differences in trap captures observed. Field tests were conducted in 2003 in Northeast Texas, the Texas Rio Grande Valley and Arkansas to ascertain if an alternative base color would improve weevil captures. The capture results with an experimental yellow base cup were equal to the commercial green (yellow-green) base cup of the Plato Trap; however, trappers reported that the alternate color was more easily seen at distances than the commercial trap. In 2004, an alternative reflective yellow base was evaluated with inconclusive results. [ABSTRACT FROM AUTHOR]

In three separate replicated field trials, extended-release pheromone dispensers containing various combinations of Grandlure, eugenol, and DDVP (dichlorvos) were compared for efficacy to attract boll weevil (Anthonomus grandis Boh.) adults to the Plato Boll Weevil Trap®. Dispensers containing Grandlure and eugenol performed better in attracting boll weevils than Grandlure dispensers without eugenol. Dispensers combining Grandlure, eugenol and DDVP into a single dispenser demonstrated performance equivalent to separate Grandlure+eugenol and DDVP dispensers. Extended-release dispensers containing 25-mg of Grandlure captured similar numbers of weevils when changed at either 21-day or 28-day intervals; however, most boll weevil eradication programs will operate on a 21-day interval during post-eradication. The use of dispensers combining Grandlure and DDVP or Grandlure, eugenol, and DDVP are a viable approach to reducing costs associated with active or post-eradication boll weevil eradication programs. [ABSTRACT FROM AUTHOR]

The cotton aphid fungus sampling service is an extension-based program that helps growers reduce input costs by predicting natural control of cotton aphids by the entompathogenic fungus, Neozygites fresenii. This fungus has been active in reducing aphid populations, particularly outbreak populations, in the Midsouth and Southeast since 1989. The aphid fungus sampling service was started in 1993 in Arkansas and has been enlarged in subsequent years. It now includes participants in Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, and South Carolina. The service is funded by Cotton Incorporated and the University of Arkansas. The service provides extension agents, consultants, researchers, and growers, with precise information on the prevalence of the aphid fungus within their fields and counties. When the fungus is actively decimating aphid populations insecticide application for cotton aphids is generally not warranted with resultant monetary savings for producers. [ABSTRACT FROM AUTHOR]

The results found in this experiment showed that the average time required for the sweep sampling method was 1:39 and the average number of tarnished plant bugs found was 1.16. When the drop sampling method was used the average time for a sample was 1:00 and the average number of tarnished plant bugs found was 0.37. The visual "whole plant" sampling method took the longest time to complete, but it also found the highest number of tarnished plant bugs. The average time taken to complete the visual sampling method was 9:18, with an average number of 1.29 tarnished plant bugs found. The average time taken to complete the square sampling method was 3:32. In this sampling method, external and internal damage was examined. The average number of tarnished plant bugs found was 0.19 and the average number of squares with external damage was 2.03; the average number with internal damage was 1.69. The bloom sampling method, which also examined the blooms for damage, found an average of 0.31 tarnished plant bugs, an average of 3.90 of the blooms were damaged and took an average time of 2:43 to complete. The last sampling method evaluated was bolls. The average amount of time required to complete a boll sample was 6:06 and the average number of bolls with external damage was 2.54 and the average number of bolls found with internal damage was 1.50. The sampling method that took the least amount of time to complete was the drop method. The average time taken to complete a drop sample was 1:00. The sampling method that took the longest time to complete was the visual "whole plant" sampling method. The average time taken to complete it was 9:18. The boll sampling method took an average time of 6:06, and the sweep sampling method took an average time of 1:39 to complete. The square sampling method took an average time of 3:32 to complete, and the bloom sampling method took an average time of 2:43 to complete. The average time taken to complete all six of these sampling methods was 24:15. The sweep sampling method found the highest number of tarnished plant bug adults. The drop sampling method found the highest number of tarnished plant bug nymphs. However, when the adults and nymphs are added together, the sweep method found 1.25 plant bugs per minute and the drop method found 1.54 plant bugs per minute. The difference between these two methods is only 0.29 plant bugs found per minute, but the sweep method still finds more plant bugs per minute. The drop sampling method also found the highest number of stinkbug adults and nymphs. Therefore, the drop sampling method proved to be more effective and efficient than any of the other sampling methods that were evaluated in this study. [ABSTRACT FROM AUTHOR]

A regional study, including Arkansas, Louisiana, Mississippi, and Tennessee, was conducted to evaluate early season thresholds for the tarnished plant bug and to determine at what level plant bug numbers impact yield in cotton. The study was a large block trial with treatment triggers for foliar applications of insecticide as follows: 1) High (16 plant bugs/ 100 sweeps); 2)Low (8 plant bugs/ 100 sweeps); 3) Automatic applications made weekly from pinhead square to bloom; and, 4) Untreated. Centric at 2 oz/ acre was used when plots triggered for application. In seven of the eight locations plant bug numbers never reached either the high or low threshold. Yields indicated that automatic applications reduced yields by 40 lbs of lint cotton per acre compared to the untreated plots. [ABSTRACT FROM AUTHOR]

An abstract of the article "2006 Louisiana Evaluation of Spatially Variable Defoliation," by R. Keith Collins, Ralph D. Bagwell, Jonathan W. Sharp, A. M. Stewart, and D. Keith Morris is presented.

The tarnished plant bug (TPB) is a primary pest of mid-south cotton. Significant changes in the status of TPB as a cotton pest have occurred over the past 10 years. These changes have occurred as a result of boll weevil eradication, bt-cotton, federal programs, and changes in cropping structure. Insecticide treatments targeting TPB have increased significantly over the past 10 years. [ABSTRACT FROM AUTHOR]

Remotely sensed imaging offers great potential as a method to base variable rate sprays of plant growth regulators (PGR) and defoliants. Normalized Difference Vegetative Index or NDVI is most often used as a method of remotely sensing plant vigor. Initially, images obtained are multi-spectral images that capture data in the green, red and near infra-red wavelengths. These images can be obtained from either a satellite or from an aircraft equipped with a multi-spectral camera. NDIV is then calculated as a ratio of light intensity in the near infra-red wavelength to the light intensity in the red wavelength. This ratio provides a relative measure of plant biomass. NDVI values are thus used as the basis for changes in rate structures of PGRs and defoliants. Little research has been conducted to evaluate variable rate applications of PGRs or defoliants, presumably because the intuitive relationship between NDVI and rate structure needs for PGRs and defoliants. Most research in this area defiantly indicates that PGR and defoliant rates can be varied without significantly impacting lint yield or quality. There are, however, limitations to NDVI images such as equal distribution of class data within the image and difficulty obtaining cloud free images. Equal distribution of class data within an NDVI means that comparisons cannot be made from field to field or on a single field over time. Research and demonstration with variable rate PGRs based on NDVI indicates that little reduction in PGR use when the grower is given the option of varying PGR rate. Growers/consultants tended to select a variable rate structure where the average use rate is similar to the rate that the grower/consultant would have used had a broad cast application been applied. Thus, when given the opportunity to make a variable rate application the producer has opted to apply a higher rate on areas with a high NDIV and a lower rate on areas with a low NDVI in comparison to the rate of PGR selected when a broadcast application is applied. Research with variable rate applications of defoliants based on NDVI indicates defoliant savings from 0 to 40% of the cost of defoliant without significant impact on lint yield or quality. The savings range is directly related to the amount of in-field variability. The 40% reduction in defoliant cost only occurred when in-field variability was extremely high (30% to 95% open bolls with considerable natural defoliation occurring) and multiple defoliant applications were made. Savings of 20 to 30% (approximately $4.00/acre) reduced defoliant costs have been common for most variable rate defoliation application. Evaluations of variable rate defoliation applications in California have indicated little in-field variability, thus no significant savings on defoliant cost using variable rate applications based on NDVI. Current application technology is such that variable rates are achieved by varying the volume output from the spray equipment. Pump capacity thus limits the variable rate applications because of a maximum output rate and speed of rate change. Application error rates are increased as the complexity of the prescription increases. Future work with variable rate applications will probably include studies that have an initial prescription basis in the historical yield and studies of new remote sensing technology such as hyper-spectral imaging. Advances in application technology will also occur. Advances such as injection systems are already available for ground based sprays and should become available for aircraft in the near future. [ABSTRACT FROM AUTHOR]