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A monitoring program evaluated the susceptibility of male bollworm, Helicoverpa zea (Boddie), populations to the pyrethroid insecticide cypermethrin using the adult vial test. Moths were trapped near cotton fields using a synthetic pheromone trap and glass vials coated with different concentrations of cypermethrin dissolved in acetone were used to assess moth mortality. Nine Texas counties were surveyed, along with Tifton in Oklahoma and Tamaulipas in Mexico, from April to September in 2009. Data were collected from all collaborators and sent to the Insect Toxicology Laboratory (AgriLife Research) for estimation of lethal concentrations (LC50 and LC90), calculation of resistance ratios, and likelihood ratio tests of equality and parallelism. Uvalde and Nueces County populations exhibited the highest LC50 resistant ratios of 9.1 and 7.6, respectively. There were only two moth survivors at 60 µg/vial, the highest dosage tested, and none at 30 µg/vial, out of nearly 4,500 moths tested. Generally, populations monitored across other counties maintained susceptibility, and populations' resistance levels for the state of Texas were similar to those observed in 2008 and lower than those registered in the previous several seasons. [ABSTRACT FROM AUTHOR]

Studies initiated in 2005 were continued in 2008 to reassess action thresholds for the cotton fleahopper, Pseudatomoscelis seriatus (Reuter). Trials in 2008 were conducted in east (Burleson Co.) and central Texas (Tom Green Co.). Treatments included one, two or three automatic insecticide applications applied one week apart, current economic threshold and an untreated check. As in previous years of the study, insecticide treatments showed no significant yield advantages. However, the trial in Burleson County indicated that yields in the insecticide treatments were numerically higher than the untreated. These findings suggest insecticide application may be provide some benefit when moderate fleahopper population levels are present throughout the fruiting season. However, currently established thresholds appear to be adequate to maintain yields. After four years, it appears that thresholds in the Southern Blacklands are adequate but questions remain about the frequency. [ABSTRACT FROM AUTHOR]

The susceptibility of the cotton bollworm, Helicoverpa zea (Boddie), to the pyrethroid insecticide cypermethrin was monitored in the main production regions of Texas though a statewide monitoring program conducted from April to September, 2007. Twelve Texas counties were surveyed, along with one location in Tamaulipas, Mexico. Moths were trapped near cotton fields using a synthetic pheromone. Glass vials coated with different concentrations of cypermethrin dissolved in acetone were used to assess moth mortality. LC50, LC90, and resistance ratios were calculated for each location. As in previous years, populations exhibiting the highest LC50 resistant ratios were from Nueces, Burleson, Williamson and Uvalde Counties. For the first time in Uvalde Co., individual moths survived high concentrations up to 60 μg/vial, and towards the end of the growing season, the LC50 resistance ratio of about 11 indicated a highly resistant population, the most resistant of 2007. Populations monitored in other Texas counties and Mexico generally maintained susceptibility. [ABSTRACT FROM AUTHOR]

The susceptibility of the cotton bollworm, Helicoverpa zea (Boddie), to the pyrethroid insecticide cypermethrin was monitored in the main production regions of Texas though a statewide monitoring program conducted from April to September, 2007. Twelve Texas counties were surveyed, along with one location in Tamaulipas, Mexico. Moths were trapped near cotton fields using a synthetic pheromone. Glass vials coated with different concentrations of cypermethrin dissolved in acetone were used to assess moth mortality. LC50, LC90, and resistance ratios were calculated for each location. As in previous years, populations exhibiting the highest LC50 resistant ratios were from Nueces, Burleson, Williamson and Uvalde Counties. For the first time in Uvalde Co., individual moths survived high concentrations up to 60 μg/vial, and towards the end of the growing season, the LC50 resistance ratio of about 11 indicated a highly resistant population, the most resistant of 2007. Populations monitored in other Texas counties and Mexico generally maintained susceptibility. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate fungicides for control of root rot (PRR), caused by the fungus Phymatotrichopsis omnivora. The experiments were done in two production areas of Texas (San Patricio and Tom Green Counties) using drip-irrigated fields with a history of severe root rot. In separate experiments, the fungicides were applied to the lower stems of plants or were injected into drip irrigation tape when plants were flowering. Also, two seed treatment fungicides were compared with a stem application of propiconazaole when plants were flowering. With stem applications, disease incidence two months after application was 29% with propiconazole at 2 lb a.i./A, as compared with 49% for the control, and 45 to 59% for the other fungicides. There was no evident root rot control when fungicides were injected through the drip tape. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate fungicides for control of root rot (PRR), caused by the fungus Phymatotrichopsis omnivora. The experiments were done in two production areas of Texas (San Patricio and Tom Green Counties) using drip-irrigated fields with a history of severe root rot. In separate experiments, the fungicides were applied to the lower stems of plants or were injected into drip irrigation tape when plants were flowering. Also, two seed treatment fungicides were compared with a stem application of propiconazaole when plants were flowering. With stem applications, disease incidence two months after application was 29% with propiconazole at 2 lb a.i./A, as compared with 49% for the control, and 45 to 59% for the other fungicides. There was no evident root rot control when fungicides were injected through the drip tape. [ABSTRACT FROM AUTHOR]

The cotton fleahopper, Pseudatomoscelis seriatus (Reuter), is considered a key pest in the eastern part of Texas. Both adults and nymphs feed on new growth, including small squares. Squares up to pinhead size are susceptible to damage and the plant is most susceptible during the first three weeks of fruiting. Cotton fleahopper numbers increase in wild hosts and move into cotton fields prior to squaring. In the Southern Blacklands, the population dynamics are consistent through years and vary only in numbers. As a result, cotton fleahoppers migrate continuously between wild hosts and cotton in this production region averages two insecticide applications for cotton fleahoppers, with a range of one to four applications depending on the populations. The situation changes in the western part of the state, including the Rolling Plains. In the western part of the state, the cotton fleahopper may increase to damaging populations occasionally. In the Southern Rolling Plains, wild host availability is limited by rainfall and cotton fleahopper populations usually remain at low levels. Cotton in this production region rarely averages more than one insecticide application for cotton fleahoppers. Recent research, performed with mechanical removal of squares which cannot duplicate the physiological impacts of insect feeding, has again shown that the newer cotton varieties have the ability to compensate for early square loss (including square losses in the second and third week of fruiting) if square removal ended after the third week. This study was initiated to evaluate cotton fleahopper control strategies in two different production regions in Texas in light of new research. Cotton fleahopper numbers were lower than normal in 2005. All treatment regimes numerically lowered numbers compared to the untreated control with significant differences in the Southern Blacklands six days after the second application. Differences in total squares per plant occurred with two automatic treatments having significantly higher numbers than the untreated control. No significant differences were seen in any of the parameters measured in the Southern Rolling Plains trial. Yields were not significantly different in either trial. [ABSTRACT FROM AUTHOR]

The cotton fleahopper, Pseudatomoscelis seriatus (Reuter), is considered a key pest in the eastern part of Texas. Both adults and nymphs feed on new growth, including small squares. Squares up to pinhead size are susceptible to damage and the plant is most susceptible during the first three weeks of fruiting. Cotton fleahopper numbers increase in wild hosts and move into cotton fields prior to squaring. In the Southern Blacklands, the population dynamics are consistent through years and vary only in numbers. As a result, cotton fleahoppers migrate continuously between wild hosts and cotton in this production region averages two insecticide applications for cotton fleahoppers, with a range of one to four applications depending on the populations. The situation changes in the western part of the state, including the Rolling Plains. In the western part of the state, the cotton fleahopper may increase to damaging populations occasionally. In the Southern Rolling Plains, wild host availability is limited by rainfall and cotton fleahopper populations usually remain at low levels. Cotton in this production region rarely averages more than one insecticide application for cotton fleahoppers. Recent research, performed with mechanical removal of squares which cannot duplicate the physiological impacts of insect feeding, has again shown that the newer cotton varieties have the ability to compensate for early square loss (including square losses in the second and third week of fruiting) if square removal ended after the third week. This study was initiated to evaluate cotton fleahopper control strategies in two different production regions in Texas in light of new research. Cotton fleahopper numbers were lower than normal in 2005. All treatment regimes numerically lowered numbers compared to the untreated control with significant differences in the Southern Blacklands six days after the second application. Differences in total squares per plant occurred with two automatic treatments having significantly higher numbers than the untreated control. No significant differences were seen in any of the parameters measured in the Southern Rolling Plains trial. Yields were not significantly different in either trial. [ABSTRACT FROM AUTHOR]

A statewide monitoring program for resistance to pyrethroids in males of bollworm (Helicoverpa zea) was conducted from April to September of 2004, surveying nine Texas counties. Moths were trapped near cotton fields using pheromone, Hercon Luretape® with Zealure. Moths were collected early in the morning and assays were performed the same day. Vials were prepared in the Toxicology Laboratory, Department of Entomology at Texas A&M University, College Station, Texas, and shipped as needed to Extension personnel. Moths from Burleson, Nueces, and Uvalde Counties, which had survivors at the highest dosage of 30 μg/vial in 2003, were tested at additional dosages of 60 and 100 μg/vial in 2004. A total of 2,070 moths were tested from Burleson County. Other counties in Texas participating in the monitoring program were: Hale, Hockley and Gaines Counties in the High Plains production region; Tom Green County in the Southern Rolling Plains region; Ellis and Williamson Counties in the Blacklands; Uvalde County in the Winter Garden region; and Nueces County in the Coastal Bend region. A total of 3,377 moths were tested for all areas outside Burleson County. Data from all areas in Texas was sent to Texas A&M University Toxicology laboratory and analyzed. Levels of resistance in Nueces County were nine times the LC50 value calculated in June for susceptible field populations studied by Kanga et al. (1996). Moths in Ellis County in July were seven times more resistant. Uvalde County had resistance ratios of six in September, and in Burleson (September), Ellis (July), and Williamson (June/July) moths were five times more resistant. Bollworm populations from Hockley County were susceptible to pyrethroids in 2004, having similar susceptibility as populations tested by Kanga et al. (1996). [ABSTRACT FROM AUTHOR]

Producers in the Southern Rolling Plains (SRP) of Texas are usually limited by moisture when producing cotton. Some producers are shifting their tillage practices from conventional to a reduced or conservation tillage program. Although conservation tillage can incorporate many different practices, producers in the SRP usually use the term to mean fewer trips and leaving more organic material at the surface. Producers are making the shift due to increasing fuel costs and managing labor and equipment costs. Producers have expressed concern that the shift to different tillage practices will lead to greater pest problems so a three year study was established to determine the impacts. In general, the shift to conservation tillage did not lead to greater pest problems. There were slight increases in grasshopper populations in the conservation tilled fields but grasshoppers never reached economic threshold levels in the three years of the study. Natural enemy populations were also impacted minimally between different tillage systems. Although advantages may be seen early in the growing season in reduced tillage systems, as with carabids, in general, neither tillage system favors natural enemies by the end of the season. [ABSTRACT FROM AUTHOR]

Producers in the Southern Rolling Plains (SRP) of Texas are usually limited by moisture when producing cotton. Some producers are shifting their tillage practices from conventional to a reduced or conservation tillage program. Although conservation tillage can incorporate many different practices, producers in the SRP usually use the term to mean fewer trips and leaving more organic material at the surface. Producers are making the shift due to increasing fuel costs and managing labor and equipment costs. Producers have expressed concern that the shift to different tillage practices will lead to greater pest problems so a three year study was established to determine the impacts. In general, the shift to conservation tillage did not lead to greater pest problems. There were slight increases in grasshopper populations in the conservation tilled fields but grasshoppers never reached economic threshold levels in the three years of the study. Natural enemy populations were also impacted minimally between different tillage systems. Although advantages may be seen early in the growing season in reduced tillage systems, as with carabids, in general, neither tillage system favors natural enemies by the end of the season. [ABSTRACT FROM AUTHOR]

Reniform nematode, Rotylenchulus reniformis, is a destructive pest of cotton in areas of Texas resulting in stand reductions, stunted plants, and reduced fiber yields. A replicated trial using two seed treatments of abamectin + thiamethoxam and thiodicarb + imidacloprid, each alone and combined with three rates of at planting in-furrow applications of aldicarb was established near San Angelo, TX. Soil samples were taken to confirm high populations of nematodes and significant stand and diseased plants were observed in the control and other treatment plots. Plots were evaluated throughout the season for stand, plant growth, and fiber yield. Treatment efficacy in terms of agronomics and fiber yield will be presented. [ABSTRACT FROM AUTHOR]

An abstract of the article "Stem Application of Fungicides for Control of Phymatotrichopsis (Cotton) Root Rot," by T. Isakeit, R. R. Minzenmayer, and Steve E. Sturtz is presented.

The objective of this study was to determine if fungicides sprayed on the lower stem could control cotton root rot, caused by the fungus Phymatotrichopsis omnivora. The experiments were done in three drip-irrigated fields in Texas, located in San Patricio County (SPC) near Tynan, and near Wall and Mereta in Tom Green County. The fungicides, thiophanate-methyl, propiconazole, azoxystrobin, and fludioxinil applied with fluazinam, were evaluated in all locations at a rate of 3.3 lb ai/A. Additionally, flusilazole and a formulation of famoxate + flusilazole were evaluated at the Tom Green County locations. The fungicides were applied using a hollow cone nozzle directed toward the lower stem in a volume of 50 GPA at 26 PSI. Plots consisted of two, 17-foot-long rows and were arranged in a randomized complete block design with four replications. Plots were located in portions of the fields with a prior history of total infection. Fungicides were applied June 23, 2005 in the SPC field, and July 6, 2005 in the Wall and Mereta fields, when plants were at 3 NAWF, 7th true leaf stage, and 12th true leaf stage, respectively. None of the fungicides adequately reduced the incidence of disease, although disease incidence was lowered and disease onset was delayed by the fungicides, in comparison with the control. An analysis of variance demonstrated significant differences in the incidence of disease between the control and some of the treatments in the Mereta (P=0.023) and Wall (P=0.033) fields, but not in SPC. By the end of the season, disease incidence was lower with the combination of fludioxinil + fluazinam at all three locations, in comparison with no fungicide treatment: 26.2% in SPC (70.4% non-treated); 77.1% in Wall (94.5% nontreated); and 78.5% in Mereta (98.8% non-treated). Propiconazole and azoxystrobin also reduced disease incidence in SPC (36.7% and 43.2%, respectively), while propiconazole and flusilazole significantly reduced disease in Wall (73.5% and 72%, respectively), and thiophanate-methyl, propiconazole and flusilazole significantly reduced disease in Mereta (83.2%, 89.1% and 86.4%, respectively). None of these fungicides are labeled for root rot control on cotton. Further experiments are needed to determine if application timing could improve the level of control. If control efficacy is improved, the cost of such applications must be weighed against the economic return. Such applications may be most economical as part of a precision agriculture program in a high input-high yield production system such as drip-irrigated cotton. [ABSTRACT FROM AUTHOR]