Cotton Squares Research Articles

Effect of Environmental Enrichment on Aggression in BALB/cJ and BALB/cByJ Mice Monitored by Using an Automated System.

Aggression among mice remains a common undesirable problem in laboratory settings, and animal welfare and scientific outcomes may become compromised depending on the severity of aggression. This study evaluated the effect of cage enrichment comprising a bilevel, mounted 'mezzanine' compared with a cotton square or shelter on intracage male aggression over a 6-wk period. Our first study involved home-cage behavioral challenges to male mice from a high-aggression substrain (BALB/cJ) and low-aggression substrain (BALB/cByJ). Aggressive interactions and locomotor activity were scored manually and then compared with measures of activity obtained by using a continuous automated home-cage monitoring system, the Digital Ventilated Caging (DVC) system. BALB/cJ mice exhibited similar levels of aggression across housing conditions, whereas BALB/cByJ mice had lower aggression when housed with a mezzanine. In the second study, videorecordings and continuous DVC automated measures were collected over 24 h and divided into 12-h light and dark phases. BALB/cByJ mice—but not BALB/cJ—mice had increased aggressive behaviors during the dark phase. However, the DVC detected higher activity levels during the dark phase, compared with the light phase, in both substrains. Elevated activity levels recorded by the DVC correlated with fighting bouts and high levels of locomotion. These results show that a bilevel structural form of enrichment reduces aggression, depending on the BALB/c substrain, and confirms higher aggression levels in the BALB/cJ substrain. In addition, our findings provide evidence that the DVC is effective in identifying mouse cages with patterns of high activity levels, signaling possible aggression incidences, thus potentially allowing for early intervention and consequently improving animal welfare.

Refined shape model fitting methods for detecting various types of phenological information on major U.S. crops

Crop phenological information is a critical variable in evaluating the influence of environmental stress on the final crop yield in spatio-temporal dimensions. Although the MODIS (Moderate Resolution Imaging Spectroradiometer) Land Cover Dynamics product (MCD12Q2) is widely used in place of crop phenological information, the definitions of MCD12Q2-derived phenological events (e.g. green-up date, dormancy date) were not completely consistent with those of crop development stages used in statistical surveys (e.g. emerged date, harvested date). It has been necessary to devise an alternative method focused on detecting continental-scale crop developmental stages using a different approach. Therefore, this study aimed to refine the Shape Model Fitting (SMF) method to improve its applicability to multiple major U.S. crops. The newly-refined SMF methods could estimate the timing of 36 crop-development stages of major U.S. crops, including corn, soybeans, winter wheat, spring wheat, barley, sorghum, rice, and cotton. The newly-developed calibration process did not require any long-term field observation data, and could calibrate crop-specific phenological parameters, which were used as coefficients in estimated equation, by using only freely accessible public data. The calibration of phenological parameters was conducted in two steps. In the first step, the national common phenological parameters, referred to as X0[base], were calibrated by using the statistical data of 2008. The SMF method coupled using X0[base] was named the rSMF[base] method. The second step was a further calibration to gain regionally-adjusted phenological parameters for each state, referred to as X0[local], by using additional statistical data of 2015 and 2016. The rSMF method using the X0[local] was named the rSMF[local] method. This second calibration process improved the estimation accuracy for all tested crops. When applying the rSMF[base] method to the validation data set (2009–2014), the root mean square error (RMSE) of the rSMF[base]-derived estimates ranged from 7.1 days (corn) to 15.7 days (winter wheat). When using the rSMF[local] method, the RMSE of the rSMF[local]-derived estimates improved and ranged from 5.6 days (corn) to 12.3 days (winter wheat). The results showed that the second calibration step for the rSMF[local] method could correct the region-dependent bias error between the rSMF[base]-derived estimates and the statistical data. A comparison between the performances of the refined SMF methods and the MCD12Q2 products, indicated that both of the rSMF methods were superior to the MCD12Q2 products in estimating all phenological stages, except for the case of the rSMF[base]-derived barley emerged stages. The phenological stages for which the rSMF[local] showed the best estimation accuracy were the corn silking stage (RMSE = 4.3 days); the soybeans dropping leaves stage (RMSE = 4.9 days); the headed stages of winter wheat (RMSE = 11.1 days), barley (RMSE = 6.1 days), and sorghum (RMSE = 9.5 days); the spring-wheat harvested stage (RMSE = 5.5 days); the rice emerged stage (RMSE = 5.5 days), and the cotton squaring stage (RMSE = 6.6 days). These were more accurate than the results achieved by the MCD12Q2 products. In addition, the rSMF[local]-derived estimates were superior in terms of the reproducibility of the annual variation range, particularly of the late reproductive stages, such as the mature and harvested stages. The crop phenology maps derived from the SMF [local] method were also in good agreement with the relevant maps derived from statistics, and could reveal the characteristic spatial pattern of the key phenological stages at the continental scale with fine spatial resolution. For example, the winter-wheat headed stage clearly became later from south to north. The cotton squaring stage became earlier from the central region towards both coastal regions.

Certain applied electrical signals during EPG cause negative effects on stylet probing behaviors by adult Lygus lineolaris (Hemiptera: Miridae)

This study is the first to fully evaluate whether electrical signals applied to large insects during electropenetrography (EPG; also called electrical penetration graph) negatively affect insect behavior. During EPG, electrical signals are applied to plants, and thus to the gold-wire-tethered insects feeding on them. The insect completes an electrical circuit whose changes in voltage reflect the insect’s stylet probing/penetration behaviors, recorded as waveform output. For nearly 50 years of EPG science, evidence has supported that there are no or negligible effects on tiny insects from applied electricity during EPG. Recently however, EPG studies of large-bodied hemipterans such as heteropterans and sharpshooter leafhoppers have been published. The wider stylet diameters of such large insects cause them to have lower inherent resistances to applied signals compared with smaller insects, conveying more electrical current. The present study asked whether such increased currents would affect insect stylet probing, by comparing Lygus lineolaris behaviors on pin-head cotton squares using an AC-DC electropenetrograph. Effects of AC or DC applied signals were separately examined in two factorial studies, each comparing four input resistor (Ri) levels (106, 107, 108 and 109 Ω) and four applied voltage levels (2, 60, 150 and 250 mV). Results showed that changes in both probing and non-probing behaviors were indeed caused by changing signal type, Ri level, or applied voltage. Negative effects on feeding were numerically greater overall for DC than AC applied signals, perhaps due to muscular tetany from DC; however, AC versus DC could not be statistically tested. Results strongly support the need for flexible Ri and applied voltage levels and types, to tailor instrument settings to the size and special needs of each insect subject. Our findings will facilitate further EPG studies of Lygus spp., such as host plant resistance or insecticidal assays/bioassays to assess mode of action and appropriate dosage. It is hoped that this study will also inform EPG studies of similar, large heteropterans in the future.

African elephants (Loxodonta africana) display remarkable olfactory acuity in human scent matching to sample performance

This paper presents data on the success rate of African elephants in human scent matching to sample performance. Working with equipment and protocols similar to those used in the training of forensic canine units in Europe, scent samples were collected on cotton squares from twenty-six humans of differing ethnic groups, sexes and ages, and stored in glass jars. Three African elephants were trained to match human body scent to the corresponding sample. In total, four hundred and seventy trials, during which the elephant handlers were blind to the experiment details, were conducted. Each trial consisted of one scent that served as the starting (target) sample to which the elephant then systematically determined a potential match in any of the nine glass jars presented. Elephants matched target and sample at levels significantly higher than indicated by random chance, displayed no loss of working memory, and successfully discriminated target odours. They also discriminated between related human individuals spanning three generations and including sibling pairs. In addition to demonstrating scent matching capabilities, this experiment supported the elephants’ significant ability to perform well at operant conditioning tasks.

Arthropod Abundance and Community Structure in Adjacent Cotton and Alfalfa on the Texas High Plains

A study was designed to examine the community composition of canopydwelling arthropods in adjacent fields of cotton, Gossypium hirsutum L., and alfalfa, Medicago sativum L., at Texas A&M University AgriLife Research and Extension Center farm near Lubbock, TX, during the cotton-growing seasons of 2008 and 2009. Samples were collected from 61 row-meter sections of cotton (1.02-m row spacing) and 61 row-meter sections of alfalfa (0.51-m spacing) via a “Keep It Simple Sampler” (KISS). Six samples were collected on each of 11 weekly sampling dates during the cotton-growing seasons of both years. We found that specimens in the canopy-dwelling arthropod community in cotton and alfalfa were from the orders Araneae, Coleoptera, Diptera, Hemiptera, Hymenoptera, Lepidoptera, Neuroptera, and Orthoptera, and in the orders, 41 families were identified. Members of Araneae, Coleoptera, and Hemiptera were most abundant in both crops. Overall, a greater number of arthropod taxa was found in alfalfa, but some arthropod taxa were unique to each crop. Analyses revealed a difference in temporal abundance of captured arthropods at the order (p ≤ 0.018) and family levels (p ≤ 0.021) during cotton squaring, flowering, and boll-development stages, with significantly greater abundance of arthropods at the order level in alfalfa compared to cotton in both years, except during the cotton-flowering period in 2008. Implications of arthropod community differences between alfalfa and cotton were discussed with respect to using alfalfa as a potential source of predators for adjacent cotton.

Correlation of Electropenetrography Waveforms From Lygus lineolaris (Hemiptera: Miridae) Feeding on Cotton Squares With Chemical Evidence of Inducible Tannins.

Probing behavior of Lygus lineolaris (Palisot de Beauvois) has previously been characterized with electropenetrography (EPG). Cell rupturing (CR) and ingestion (I) EPG waveforms were identified as the two main stylet-probing behaviors by adult L. lineolaris. However, characterization and identification of EPG waveforms are not complete until specific events of a particular waveform are correlated to insect probing. With the use of EPG, histology, microscopy, and chemical analysis, probing behavior of L. lineolaris on pin-head cotton squares was studied. Occurrences of waveforms CR and I were artificially terminated during the EPG recording. Histological samples of probed cotton squares were prepared and analyzed to correlate specific types and occurrences of feeding damage location and plant responses to insect feeding. Both CR and I occurred in the staminal column of the cotton square. Cell rupturing events elicited the production of dark-red deposits seen in histological staining that were demonstrated via chemical analysis to contain condensed tannins. We hypothesize that wounding and saliva secreted during CR triggered release of tannins, because tannin production was positively correlated with the number of probes with single CR events performed by L. lineolaris. Degraded plant tissue and tannins were removed from the staminal column during occurrence of waveform I. These results conclude the process of defining CR and I as probing waveforms performed by L. lineolaris on pin-head cotton squares. These biological definitions will now allow EPG to be used to quantitatively compare L. lineolaris feeding among different plant treatments, with the goal of improving pest management tactics against this pest.

Discrimination of infested cotton squares by females of Anthonomus grandis

The avoidance of infested squares of Gossypium hirsutum as oviposition substrate by females of Anthonomus grandis was studied following two approaches. First, the preference for oviposition in infested versus non-infested squares was studied in laboratory. Second, the distribution of ovipositions by A. grandis in nature was analyzed in cotton plots from Argentina. In addition, the consequences of multiple ovipositions were assessed in terms of emergence rate, adult weight and sex ratio. In the laboratory, the number of ovipositions was significantly higher in non-infested than in infested squares. Likewise, females were found to reject infested squares more frequently than non-infested squares. In the field, oviposition pattern fitted a uniform distribution for squares collected from the ground, while the distribution in squares sampled from the plant fitted random and uniform distributions. This suggests that oviposition decisions could be dynamic and change with the infestation conditions. Multiple ovipositions resulted in the elimination of competing larvae between L1 and L2 instars. The weight of the individual that develops to the adult stage was negatively affected by the level of larval competition, and the sex ratio deviated toward females. Our results suggest that females of A. grandis tend to avoid already infested squares. This behavior would allow reducing the levels of intraspecific competition, which we also found can seriously affect the development of their progeny. A deeper knowledge of the oviposition behavior of A. grandis could contribute to developing control methods against this important cotton pest.

Cover Image, Volume 73, Issue 4

The cover image of a scentless plant bug feeding on a cotton square is based on the Perspective Perspectives on the agrochemical industry and agrochemical discovery, by Thomas C. Sparks and Beth A Lorsbach, DOI: 10.1002/ps.4457. Photo Credit: William Fisher – Hillsborough, North Carolina. image

Survival pattern of the boll weevil during cotton fallow in Midwestern Brazil

Abstract: The objective of this work was to determine the survival pattern of the cotton boll weevil during fallow in Midwestern Brazil. The percentage of adults that remained in the cotton reproductive structures, the percentage of adults searching for shelters, and the longevity of adults fed on pollen and nectar as alternative food sources were determined. For this, four populations were sampled in cotton squares and bolls, totaling 11,293 structures, from 2008 to 2012. The emergency of cotton weevil adults was monitored from the collection of the structures until the next cotton season. In the laboratory, newly-emerged adults were fed on hibiscus or Spanish needle, and their life span was monitored individually. Most adults (85.73%) left the reproductive structures, regardless of the cotton plant phenology, up to 49 days after the structures were collected. One individual (0.0002%) from 5,544 adults was found alive after the fallow period. The diet with hibiscus and Spanish needle provided adult longevity of 76±38 days, which was enough time for adults to survive during the fallow period. Most of the boll weevils leave the cotton structures at the end of harvest, survive using alternative food sources, and do not use cotton plant structures as shelter during the legal cotton fallow period in Midwestern Brazil.

Spatial and temporal distribution of cotton squares and small cotton bolls fallen on ground after damage by boll weevil and the efficiency of the equipment used to collect them

ABSTRACT: In this study, we determined the spatial and temporal distribution of fallen cotton squares and small cotton bolls fallen damaged by boll weevil and the efficiency and time interval of the equipment used to collect cotton samples. Spatial and temporal distribution of cotton squares and small cotton bolls fallen on the soil damaged by boll weevil among cotton rows was determined in an experimental design of randomized blocks in a factorial arrangement of 4x3, represented by soil surface tracks located at 1-11cm, 12-22cm, 23-33cm, and 34-44cm away from the planting row of cotton plants 70, 85, and 100 days of age. Efficiency and collection time interval of the cotton samples fallen on the soil infested by boll weevil by plastic rakes that were straight or fan-shaped, big broom, collector instrument model CNPA and aspirator of leaves ‘Trapp’ were determined in randomized block design with five treatments, 10 repetitions for each. Results demonstrated that the collection of cotton samples must be performed with greater attention to soil strips located below the cotton top projection and aspirator ‘Trapp’ of leaves was more appropriate for the operation as it used less time of collection with similar efficiency to other available equipment.

Aqueous washings of host plant surface influence the growth inhibitory effects of δ‐endotoxins ofBacillus thuringiensisagainstHelicoverpa armigera

AbstractBiological activity of the bacteriumBacillus thuringiensisBerliner (Bt) against insect pests is influenced by the host plants. To understand the underlying mechanism of variation in biological activity of Bt on host plants, we studied the effect of chemicals from the surface of chickpea (Cicer arietinumL.,Fabaceae) leaves (ICCC37 andICC506EB), sorghum [Sorghum bicolor(L.)Moench,Poaceae] grain (ICSV745 andIS18698), pigeon pea [Cajanus cajan(L.) Millsp.,Fabaceae] pods (ICPL87 andICPL332WR), and cotton (Gossypium hirsutumL.,Malvaceae) squares (RCH2 and BtRCH2), on whichHelicoverpa armigera(Hübner) (Lepidoptera:Noctuidae) feeds under natural conditions. Surface chemicals extracted in water from host plant leaves were added to the standard artificial diet containing a commercial formulation of Bt or Cry1Ac. Data were recorded on larval and pupal weights, pupation, adult emergence, larval and pupal periods, adult longevity, and fecundity. Weights ofH. armigeraat 5 days after initiation of the experiment were significantly reduced on artificial diets containing Bt + pod washings ofICPL87 andICPL332WR, grain washings ofICSV745, or square washings ofRCH2, and Cry1Ac + leaf‐surface washings ofICC506EB. Pupal weights were lower on diets containing leaf‐surface washings ofICCC37 + Bt than on standard artificial diet. Larval periods were prolonged on diets containing Bt + leaf‐surface washings ofICCC37, pod washings ofICPL87, and square washings ofRCH2, and on standard artificial diet + Cry1Ac. Pupation was significantly higher on standard artificial diet + Cry1Ac than on diets with Bt + grain washings ofICSV745 and Cry1Ac + square washings ofRCH2 and BtRCH2. Adult emergence was lowest on diets with square washings ofRCH2 + Bt and grain washings ofICSV745 + Cry1Ac. The results suggested that leaf‐surface washings play an important role in biological activity of Bt/Cry1Ac againstH. armigera.

Characterization of an EPG Waveform Library for AdultLygus lineolarisandLygus hesperus(Hemiptera: Miridae) Feeding on Cotton Squares

Lygus lineolaris (Palisot de Beauvois) and Lygus hesperus Knight are among the most important pests affecting production of cotton in the United States. Lygus spp. use a cell rupture feeding strategy. However, the precise stylet-probing behaviors of adult Lygus spp. are not well understood or quantifiably related to cotton damage. The long-term goals of our research are to: 1) relate stylet probing to damage, and 2) quantitatively compare L. lineolaris feeding among resistant and susceptible host plants. The specific objectives of this study were to apply the latest technology in electropenetrography (EPG) to record adult, prereproductive Lygus spp. feeding, to identify and characterize all the waveforms, and to hypothesize their biological meanings. We used a third-generation AC–DC electropenetrograph to record nonprobing and probing waveforms of adult bugs on pinhead (<3 mm) cotton squares, and constructed a waveform library from the output. Recordings were obtained with both AC and DC applied signals and at different input impedances (106–109 Ω). Three nonprobing waveforms were identified and visually correlated: Standing still (S), walking (W), and antennation (A). Probing waveforms were classified as: cell rupturing (CR), transition (T), and ingestion (I). T waveform is the first finding of an X wave for a nonsalivary sheath feeder in Hemiptera, implying that tasting/testing/acceptance behaviors can be performed by a cell rupture feeder. While waveform I is not performed in every probe, when performed, its appearance and structure were affected by applied signal and input impedance. Overall, time spent in nonprobing behaviors was longer than time spent on probing behaviors.

Use of an Insect Growth Regulator Applied at the Second Week of Cotton Squaring for Management of Lygus Bugs, 2015: Table 1

A commercial cotton field planted with cv. ‘DP 164’ Round-Up Ready cotton was selected with alfalfa fields adjacent on two sides prior to establishment of experimental plots. The experiment consisted of a split plot design with a whole-plot (≈3.39 ha each) factor of either a foliar application of Diamond (novaluron) or Carbine (flonicamid) applied during the second week of squaring. The sub-plot factor consisted of eight individual treatments replicated three times ( n = 3) within each main-plot in a randomized complete block design. Plot size for sub-plots was eight rows wide with a total area of ≈0.14 ha. Sub-plot treatments were applied three times at 7–10 d intervals following the recommended labeled …

Cotton Square Morphology Offers New Insights into Host Plant Resistance to Cotton Fleahopper (Hemiptera: Miridae) in Upland Cotton

Cotton fleahopper, Pseudatomoscelis seriatus (Reuter) (Hemiptera: Miridae), is a piercing-sucking pest of cotton (Gossypium hirsutum L.) that feeds preferentially on developing flower buds, called squares. Heavy infestations cause yield reductions that result from abscission of squares damaged by the cotton fleahopper feeding. Antixenosis, or nonpreference, has been reported as a mechanism of host plant resistance in cotton to cotton fleahopper. Square structure, particularly the placement of the reproductive tissues, and stylet penetration were investigated as factors that influence resistance to cotton fleahopper in cotton lines derived from crosses with Pilose, a cultigen of upland cotton resistant to cotton fleahopper, and backcrossed with high-yielding, susceptible lines. Ovary depth varied among the lines tested and was found to be a heritable trait that affected the ability of a fleahopper's feeding stylets to penetrate the reproductive tissues in the square and might influence preference. Behavioral assays suggested antixenosis as a mechanism of host plant resistance, and the trait conferring antixenosis was found to be heritable. Results suggest ovary depth plays a role in conferring resistance to cotton fleahopper and is an exploitable trait in resistance breeding.

Concentração eficiente e econômica de caulim para a proteção de algodoeiro contra o bicudo

Resumo:O objetivo deste trabalho foi determinar a concentração de caulim mais eficiente e econômica para a proteção de algodoeiro contra os danos causados pelo bicudo-do-algodoeiro (Anthonomus grandis). Utilizou-se o delineamento experimental de blocos ao acaso, com cinco tratamentos de pulverizações com caulim nas concentrações: 20, 40, 60, 80 e 100 g L-1. Determinaram-se os seguintes parâmetros: percentagem de botões florais com orifícios de oviposição por fêmeas do bicudo; resíduos de caulim depositados sobre as folhas e as brácteas do algodoeiro; média da produção; e receita líquida do algodão, por hectare, a partir da pesagem da pluma de algodão com caroço. As percentagens de botões florais com orifício de oviposição variaram de 13,6 a 30,8%; o resíduo médio de caulim depositado nas folhas, de 0,0010 a 0,0034 mg mm-2, e nas brácteas, de 0,0010 a 0,0034 mg mm-2; a produção variou de 348,1 a 717,8 kg ha-1; e a receita líquida de algodão de R$ 1.033,88 a R$ 2.098,86 por hectare. As concentrações de caulim mais eficientes para a proteção de algodoeiro contra o bicudo são as de 60, 80 e 100 g L-1; no entanto, a de 60 g L-1foi a mais econômica.

Assessing nest-building behavior of mice using a 3D depth camera

We developed a novel method to evaluate the nest-building behavior of mice using an inexpensive depth camera. The depth camera clearly captured nest-building behavior. Using three-dimensional information from the depth camera, we obtained objective features for assessing nest-building behavior, including “volume,” “radius,” and “mean height”. The “volume” represents the change in volume of the nesting material, a pressed cotton square that a mouse shreds and untangles in order to build its nest. During the nest-building process, the total volume of cotton fragments is increased. The “radius” refers to the radius of the circle enclosing the fragments of cotton. It describes the extent of nesting material dispersion. The “radius” averaged approximately 60mm when a nest was built. The “mean height” represents the change in the mean height of objects. If the nest walls were high, the “mean height” was also high. These features provided us with useful information for assessment of nest-building behavior, similar to conventional methods for the assessment of nest building. However, using the novel method, we found that JF1 mice built nests with higher walls than B6 mice, and B6 mice built nests faster than JF1 mice. Thus, our novel method can evaluate the differences in nest-building behavior that cannot be detected or quantified by conventional methods. In future studies, we will evaluate nest-building behaviors of genetically modified, as well as several inbred, strains of mice, with several nesting materials.

Laboratory Evaluation of Transgenic Bt Cotton (cry1Ac +cry2Ab genes) and Non-Bt Cotton against Neonates, First and Second Instar Larvae of Spodoptera litura Fab.

Transgenic Bt cotton BG II (cry1Ac +cry2Ab genes) in comparison with non-Bt cotton were evaluated for their effect on the development of Spodoptera litura in the IPM Laboratory of Department of Entomology, Punjab Agricultural University Ludhiana. The leaf and square of various Bt cotton cultivars viz. MRC 7017, BCHH 6488, BCHH 6588, Ankur 3028, NCS 855 and non-Bt cotton LH 2076 were fed to the neonates, first and second instars larvae of cotton leaf worm, S. litura. The neonates, 1st and 2nd instar larvae when fed on leaves of transgenic Bt cotton resulted in 100 per cent mortality as compared to non-Bt cotton (0.00). However, 2nd instar larvae fed on squares of Bt cotton resulted in 100 per cent mortality in most of the Bt cotton cultivars, MRC 7017, BCHH 6488, BCHH 6588 and Ankur 3028 except NCS 855 (82.16) and non-Bt (6.63). The developmental times of 2nd instar larvae of S. litura were different among Bt cotton cultivars and non-Bt cotton. The survived 3rd instar larvae fed on leaves in Ankur 3028 (11.11) followed by BCHH 6588 (7.14) and BCHH 6488 (7.4) continued to be 3rd instar even after 17 days, while those on non Bt cotton moulted to pupal stage (7.14). However, when larvae fed on squares of Bt cotton and non-Bt cotton, maximum pupation takes place in non Bt cotton cultivar, LH 2076 (93.33) followed by Bt cotton cultivar NCS 855 (17.85) after 24 days. The total developmental time of larvae in the Bt cotton was significantly longer than that of larvae on non-Bt squares. The higher weight of larvae fed on leaves was recorded in LH 2076 (19.72 mg). Similarly, after 10 days of release of S. litura on squares of different cotton cultivars higher weight of larvae was recorded in LH 2076 (25.671 mg) and lower in MRC 7017 (2.919 mg). The pupae that developed from the larvae that fed on non-Bt were heavier than those that developed from the larvae that fed on non-Bt cotton squares. After 27 days, 100 per cent adult emergence was recorded in non-Bt cotton cultivar, LH 2076 followed by single emergence in BG II cotton cultivar NCS 855. However, after 31 days, four adults were formed in case of NCS 855 but they were not able to survive for more than 2 days and all of them were males. It can be inferred that all BGII cotton cultivars were toxic to neonates, first and second instar larvae of S. litura under laboratory conditions.

Crop hosts and genotypic resistance influence the biological activity of Bacillus thuringiensis towards Helicoverpa armigera

Studies on the influence of genotypic resistance on biological activity of a commercial formulation of Bacillus thuringiensis (Bt) and pure Bt toxin Cry1Ac were carried out to develop appropriate strategies for pod borer, Helicoverpa armigera management in chickpea, sorghum, pigeonpea and cotton. The interaction effects of host plant resistance and biological activity of commercial Bt/Cry1Ac were studied by incorporating the lyophilized tissues of chickpea leaves, milk stage sorghum grain, pigeonpea pods and cotton squares into the artificial diet with and without Bt formulation or Cry1Ac. The H. armigera larval weights were significantly lower in insects reared on diets with square powder of the insect - resistant Bt-cotton RCH 2 + Bt/Cry1Ac and pod powder of insect - resistant pigeonpea genotype, ICPL 332WR + Bt/Cry1Ac as compared to the larvae reared on diets with leaf powder of H. armigera susceptible chickpea genotype, ICCC 37 and the standard artificial diet. Pupation and adult emergence were significantly lower in insects reared on diets with tissues of pod borer-resistant genotypes + Bt/Cry1Ac as compared to insects reared on diets with tissues of the insect susceptible genotypes + Bt/Cry1Ac. Insects reared on diets containing insect-resistant and -susceptible genotypes of sorghum, pigeonpea and cotton and pod borer-resistant genotype of chickpea (ICC 506EB) + Bt/Cry1Ac did not lay any eggs. However, eggs were laid by the insects reared on diets containing pod borer-susceptible genotype of chickpea, ICCC 37 and on the standard artificial diet + Bt/Cry1Ac. The insects reared on diets with sorghum genotype, ICSV 745, and Bt-cotton, RCH 2 without Bt/Cry1Ac also did not lay eggs. The results suggested that Bt/Cry1Ac is more effective for management of H. armigera when deployed in combination with insect-resistant genotypes of cotton, chickpea, pigeonpea and sorghum.

Individual human odor fallout as detected by trained canines

We tested the hypothesis that if odor fallout (the release of a human's odor onto an untouched object) in human subjects exists, then holding a hand above an absorbent will produce a detectable scent which will be subsequently matched in a detection test by trained canines. Scents were collected from seven males to sterile cotton absorbent squares. The left hand was used to get the control scent and the right hand served as the target scent. Each experimental subject was sitting; his left hand was laid down on a cotton square for 3min. The right hand was held 5cm above another cotton square for 3min. The scent identification was done by two specially trained police German shepherds. These canines had routinely performed scent identification line-ups as part of criminal investigation procedures. Both canines performed 14 line-ups and correctly matched the collected scents of all test subjects. The results suggest the existence of human odor fallout, whereby a human scent trace is left by humans even if they do not touch an object.

Response by Lygus hesperus (Hemiptera: Miridae) Adults to Salivary Preconditioning of Cotton Squares

Response by Lygus hesperus (Hemiptera: Miridae) Adults to Salivary Preconditioning of Cotton Squares