Importance of Fungicide Seed Treatment and Environment on Seedling Diseases of Cotton.

The importance of fungicide seed treatments on cotton was examined using a series of standardized fungicide trials from 1993 to 2004. Fungicide seed treatments increased stands over those from seed not treated with fungicides in 119 of 211 trials. Metalaxyl increased stands compared to nontreated seed in 40 of 119 trials having significant fungicide responses, demonstrating the importance of Pythium spp. on stand establishment. Similarly, PCNB seed treatment increased stands compared to nontreated seed for 44 of 119 trials with a significant response, indicating the importance of Rhizoctonia solani in stand losses. Benefits from the use of newer seed treatment chemistries, azoxystrobin and triazoles, were demonstrated by comparison with a historic standard seed treatment, carboxin + PCNB + metalaxyl. Little to no stand improvement was found when minimal soil temperatures averaged 25°C the first 3 days after planting. Stand losses due to seedling pathogens increased dramatically as minimal soil temperatures decreased to 12°C and rainfall increased. The importance of Pythium increased dramatically as minimal soil temperature decreased and rainfall increased, while the importance of R. solani was not affected greatly by planting environment. These multi-year data support the widespread use of seed treatment fungicides for the control of the seedling disease complex on cotton.

Evaluation of Several Approaches to Manage Meloidogyne incognita and Cotton Seedling Disease Complexes in the High Plains of Texas.

Field experiments were conducted for control of the southern root-knot nematode (Meloidogyne incognita) and cotton seedling disease fungi (primarily Thielaviopsis basicola) in one naturally infested field during 1999 and 2000 and in three additional fields in 2000. Treatments included: seed-applied fungicides (triadimenol + mefenoxam + thiram and carboxin + PCNB + mefenoxam), cultivars (Paymaster [PM] 2326 RR and PM 2200 RR), and a nematicide (aldicarb at 0.83 kg a.i/ha). Plant stands were higher (P = 0.02) in the presence of aldicarb (77% emergence) than in its absence (74% emergence). Hypocotyl disease symptom ratings were lower (P = 0.0001) following triadimenol + mefenoxam + thiram seed treatment (0.53) as compared with carboxin + PCNB + mefenoxam (0.93). Root necrosis was lower (P = 0.002) following triadimenol + mefenoxam + thiram seed treatment (27%) as compared with carboxin + PCNB + mefenoxam (34%). In one field, in both years, aldicarb was associated with more root necrosis (58%) than in its absence (46%) (P = 0.004). At three other sites aldicarb did not affect root necrosis. Population densities of Meloidogyne incognita eggs and juveniles at midseason were greater (P = 0.005, P = 0.003, respectively) on PM 2200 RR (less resistant) than on PM 2326 RR (more resistant). Yield was affected by the plant genotype by aldicarb interaction (P = 0.02) but not by seed treatments. Aldicarb effect on yield was dependent on cultivar, whereas affect of seed treatment on root health was consistent and independent of cultivar and aldicarb. No conditions were identified when use of triadimenol + mefenoxam was detrimental.

Relationship of Aerial Broad Band Reflectance to Meloidogyne incognita Density in Cotton.

Aerial images were obtained on 22 July 1999 and 4 August 2000 from five cotton sites infested with Meloidogyne incognita. Images contained three broad bands representing the green (500-600 nm), red (600-700 nm), and near-infrared (700-900 nm) spectrum. Soil samples were collected and assayed for nematodes in the fall at these sites. Sampling locations were identified from images, by locating the coordinates of a wide range of light intensity (measured as a digital number) for each single band, and combinations of bands. There was no single band or band combination in which reflectance consistently predicted M. incognita density. In all 10 site-year combinations, the minimum number of samples necessary to estimate M. incognita density within 25% of the population mean was greater when sampling by reflectance-based classes (3 to 4 per site) than sampling based on the entire site as one unit. Two sites were sampled at multiple times during the growing season. At these sites, there was no single time during the growing season optimal to take images for nematode sampling. Aerial infrared photography conducted during the growing season could not be used to accurately determine fall population densities of M. incognita.

Clinical evaluation of the effect of a remineralizing toothpaste on dentinal sensitivity.

Dentinal hypersensitivity is a common dental problem without a satisfactory solution. Most therapies have focused on either trying to block the stimulation of dentinal nerves or on sealing open dentinal tubules. This study evaluated, in a double blind clinical trial, the effect of Enamelon, a dentifrice containing sodium fluoride, calcium salts and phosphate salts (calcium separated from the phosphate and fluoride by a plastic divider in the tube to prevent interaction) on dentinal hypersensitivity over an 8-week period. A conventional OTC dentifrice containing NaF without calcium and phosphate enhancement served as the control. A third dentifrice, containing sodium monofluorophosphate enhanced by calcium and phosphate salts, was also tested. Based upon subjective anecdotal information, net numbers of sensitive teeth which became non-sensitive, and a logit analysis of the change in the proportion of sensitive teeth over the study time period, Enamelon was the most effective product, and the OTC control the least effective.

Comparison of Variable and Single-Rate Applications of Aldicarb on Cotton Yield in Fields Infested with Meloidogyne incognita.

Variable-rate applications of the nematicide aldicarb were compared to producer standard rates in eight field tests over 3 years. Test areas (308 to 1,015 m long) were divided into eight or five blocks. Each block contained two plots with a variable-rate treatment (VRT) of aldicarb and a producer standard treatment (PST) of aldicarb. Each VRT plot was divided into three subunits and intensively sampled for Meloidogyne incognita in either the fall or spring before planting. Rates of aldicarb were assigned to each subunit for VRT based on M. incognita population density. In three of the eight tests, VRT resulted in either higher yield or similar yields, but less nematicide applied. In two tests there were no differences between PST and VRT in yields or average rates of aldicarb applied. In three tests, VRT used more aldicarb (>0.17 kg a.i./ha difference) than PST and yields were not significantly different between treatments. In two of the cases where VRT was superior to PST, the producer's rate of aldicarb was judged to be either too low or too high for the average M. incognita density present in the field. In all three cases where PST was superior to VRT, perennial weeds were an important factor also limiting yield. Variable-rate application of aldicarb did not consistently provide for higher yields or lower nematicide usage than standard application rates.

Measurement of tooth hypersensitivity and oral factors involved in its development.

The various methods of measurement of dentinal hypersensitivity are based upon the types of stimuli used to elicit a pain response in teeth, which include thermal, tactile, evaporative, electrical and osmotic. Pulpal inflammation in its early stages reduce the threshold of pain response to these stimuli but electrical stimulation may make it possible to assess the possible contribution of such inflammation to sensitivity determinations. Although the magnitude of each stimulus is quantifiable, patient response is subjective, which necessarily makes measurements of dentinal sensitivity semisubjective. Various methods of testing dentinal sensitivity are discussed, along with their advantages and disadvantages. The teeth most suited for measurement in clinical studies are the canines and premolars. This is because approx. 80% of the sensitivity lesions are associated with these teeth, which have similar thicknesses of root dentine. Data from several studies involving the same subjects indicate that individual measurements readily return to baseline and that the commonly seen placebo effect is probably due to some as yet unidentified factor in desensitizing formulations. Possible roles of salivary and plaque environmental factors in the development of dentinal sensitivity are discussed, as well as methods for their measurement.

Design and statistical aspects of the management of clinical trials to assess antihypersensitivity product efficacy.

This paper discusses the design of clinical trials for testing the efficacy of therapeutic products for hypersensitive teeth with emphasis on statistical considerations. The preparation of a proper protocol is essential to the successful outcome of any clinical study. Key considerations in this regard are the criteria for patient selection, the size of the sample, the method of stratification of subjects into various test and control groups, the methods to be used for assessing sensitivity, and the statistical treatment of the data generated. The importance of other factors such as the requirement for a quiet, relaxed atmosphere and allowing adequate time for the examiner to establish a rapport with the subject, and the need to comply with institutional review board regulations, are stressed.

Use of multiple sensitivity measurements and logit statistical analysis to assess the effectiveness of a potassium-citrate-containing dentifrice in reducing dentinal hypersensitivity.

A potassium citrate-SMFP containing dentifrice was tested in a double-blind 8-week clinical trial on subjects with a history of dentinal hypersensitivity. A dentifrice containing SMFP but no potassium salt was used as the control and a 2nd test dentifrice containing potassium nitrate-SMFP was assessed at the same time. The sensitivity of the subjects was evaluated at 0, 3 and 8 weeks using electrical and tactile methods plus a 1-s air blast. The sensitivity scores for each subject at each examination were summarised as a proportion of the examined teeth deemed sensitive. Assessment of any effects of the dentifrices was via an analysis of covariance of the logit transformation of these proportions with the baseline value as the covariate. The use of this novel method of analysis had the advantage of taking into account changes in sensitivity of all of the teeth, both sensitive and non-sensitive, since electrical measurements indicated effects on both. Of the original 120 subjects, 111 completed the trial and the 3 dentifrice groups remained well balanced for age, sex and sensitivity. All 3 dentifrice groups showed statistically significant reductions in sensitivity over the 8 weeks. However, the potassium citrate-SMFP dentifrice was significantly more effective than either the control SMFP dentifrice, or the potassium nitrate-SMFP dentifrice, at reducing sensitivity after 3 weeks, and this difference plus further sensitivity reduction with all 3 dentifrices was observed after 8 weeks.

Pilot study comparing the salivary cationic protein concentrations in healthy adults and AIDS patients: correlation with antifungal activity.

This investigation compared the salivary cationic protein concentrations of 12 healthy adult controls with those of 12 hospitalized patients with AIDS. Salivas were quantified by capillary electrophoresis using purified cationic protein standards. In parotid saliva, histidine-rich polypeptides (HRPs) 1-6, histatin 6, and lysozyme concentrations were determined. In addition to these eight cationic proteins, submandibular-sublingual saliva was also quantified for histatin 2 and the histatin 2 degradation product. When comparisons were made on the basis of individual proteins, the HRP-histatin concentrations in the AIDS patients showed either statistically significant decreases or a decreasing trend compared with healthy adult controls. When HRP-histatin concentrations were summed for each patient, there were statistically significant differences between the healthy adult controls and the individuals with AIDS in both parotid and submandibular-sublingual salivas. Closer examination revealed that some individuals with AIDS had HRP-histatin concentrations that fell within the normal range of the healthy adult controls. For these individuals, lower than expected salivary antifungal values were obtained. Either decreasing histidine-rich protein concentrations and/or an inability of these proteins in saliva to interact with Candida albicans may contribute to the defective salivary antifungal activity seen in AIDS patients.

Determination of salivary anticandidal activities in healthy adults and patients with AIDS: a pilot study.

This investigation compared the salivary anticandidal activities of 12 healthy adults with 12 hospitalized patients with AIDS. Stimulated parotid, submandibular-sublingual, and whole salivas were collected during a period of 10 min, immediately acidified, boiled, and then centrifuged to isolate salivary supernatants. Supernatants were then tested for antifungal activity against Candida albicans in blastospore viability inhibition and germ tube formation assays. A unit of blastospore or germ tube antifungal activity was established as that activity yielding 90% or greater inhibition during a defined time period in each salivary assay. Each of the patients with AIDS were found to be defective in one or more of their salivary antifungal activities, and in comparison with healthy adults the differences in antifungal units per milliliter of saliva and total antifungal units were statistically significant for each saliva and each antifungal assay. Defective salivary antifungal activity may contribute to the oral candidiasis seen in patients with AIDS.

Caries prevalence, treatment level, and sealant use related to school lunch program participation.

A total of 2,753 schoolchildren (8-11 years old) from two school districts received visual-tactile examinations for caries. The school districts were approximately 15 miles apart and located in fluoride-deficient (F less than 0.3 ppm) Long Island, New York. The higher socioeconomic community (HSES) had 9.2 percent of its students enrolled in the free or reduced-payment school lunch program; the lower socioeconomic community (LSES) had 50.3 percent enrolled. The LSES community had a higher caries prevalence, more untreated lesions, fewer caries-free children, and fewer children treated with sealants. School lunch programs provide an index to identify communities for dental programs.