Host-free Survival of Boll Weevils (Coleoptera: Curculionidae) from Two Regions of Texas

New information regarding boll weevil, Anthonomus grandis Boheman, overwintering is important to efforts to improve efficiency of eradication efforts. The boll weevil diapause remains a contentious issue despite intense study and some evidence suggests the diapause response differs among weevil populations

Effect of different irrigation water level on cotton yield and yield components

Effects of different water level on yield and yield components of the drip irrigated cotton were evaluated in Amik Plain in the East Mediterranean Region of Turkey. Four levels of irrigation water were tested in2003 and 2004. Treatments were 25 (I25), 50 (I50), 75% (I75) of the full irrigation treatment (I100) which received 100% class-A pan evaporation. Numbers of irrigation events were 5 and 8 in 2003 and 2004, respectively. Under I25, I50 and I75 treatment conditions, evapotranspiration, total cotton seed yield, boll weight, lint percentage, number of sympodial branches and leaf area index decreased while some boll parameters such as boll weights and opened boll numbers increased. Increase of boll number per plant under water stress condition showed that cotton had high ability for adapting water stress conditions. The highest yield was obtained in the I100 treatment. A second degree polynomial relation could adequately describe the cotton seed yield response to the irrigation water amount. The highestirrigation water use efficiency (IWUE) was obtained with the I50 treatment

From minimal Lagrangian to J-minimal submanifolds: persistence and uniqueness

Given a minimal Lagrangian submanifold L in a negative Kaehler--Einstein manifold M, we show that any small Kaehler--Einstein perturbation of M induces a deformation of L which is minimal Lagrangian with respect to the new structure. This provides a new source of examples of minimal Lagrangians. More generally, the same is true for the larger class of totally real J-minimal submanifolds in Kaehler manifolds with negative definite Ricci curvature.Comment: Final version, 22 pages; to appear in a special volume in memory of Paolo de Bartolomeis, Boll. UM

Linearizability and fake Lax pair for a consistent around the cube nonlinear non-autonomous quad-graph equation

We discuss the linearization of a non-autonomous nonlinear partial difference equation belonging to the Boll classification of quad-graph equations consistent around the cube. We show that its Lax pair is fake. We present its generalized symmetries which turn out to be non-autonomous and depending on an arbitrary function of the dependent variables defined in two lattice points. These generalized symmetries are differential difference equations which, in some case, admit peculiar B\"acklund transformations.Comment: arXiv admin note: text overlap with arXiv:1311.2406 by other author

Boll Weevil (Coleoptera: Curculionidae) Feeding and Reproduction as Functions of Cotton Square Availability

The influence of food item availability on boll weevil, Anthonomus grandis grandis Boheman, feeding and reproduction was determined by providing different numbers of cotton squares (flower buds) to individual weevils. Squares were replaced daily after a 5-d feeding and mating conditioning period. The number of lifetime punctures produced by boll weevil females and males increased with square availability. The total number of punctures caused by boll weevil females was 2.7-fold higher than that caused by males. Fecundity was significantly higher in the 10:1, 15:1, and 20:1 (squares:female) treatments than in the 1:1 treatment. The relationship between eggs laid per day and the square to female ratio significantly changed over the life of the female, with the largest differences among treatments occurring in the first 3 wk of adulthood. Survival of weevil progeny to adulthood was about two-fold higher in the 10:1, 15:1, and 20:1 treatments than in the 1:1 and 5:1 treatments. When each boll weevil female was provided 10, 15, or 20 cotton squares per day, estimates of a population growth index (percent of immatures surviving to adulthood divided by immature development time) and the exponential rate of increase (rm) were significantly higher than for those provided only one or five squares per day. Boll weevil populations maintained at a square:weevil ratio of 10:1 or above will increase \u3e60-fold each generation (Ro), a rate significantly higher than that exhibited under 5:1 or 1:1 square:female regimens. These data show that daily provision of 10 squares per female provides sufficient resources to elicit a maximal oviposition response in the laboratory. Our results also will be useful in predicting changes in boll weevil populations relative to crop phenology and starting population density

On some differential-geometric aspects of the Torelli map

In this note we survey recent results on the extrinsic geometry of the Jacobian locus inside $\mathsf{A}_g$. We describe the second fundamental form of the Torelli map as a multiplication map, recall the relation between totally geodesic subvarieties and Hodge loci and survey various results related to totally geodesic subvarieties and the Jacobian locus.Comment: To appear on Boll. UMI, special volume in memory of Paolo de Bartolomei

Influence of two acyclic homoterpenes (Tetranorterpenes) on the foraging behavior of anthonomus grandis Boh

Previous studies have shown that the boll weevil, Anthonomus grandis, is attracted to constitutive and conspecific herbivore-induced cotton volatiles, preferring the blend emitted by cotton at the reproductive over the vegetative stage. Moreover, this preference was paralleled by the release of the acyclic homoterpenes (tetranorterpenes) (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT) and (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT) in Delta Opal cotton being higher at the vegetative than at the reproductive stage. Here, we evaluated whether this difference in release of acyclic homoterpenes also occurred in other cotton varieties, and if boll weevils could recognize these compounds as indicators of a specific cotton phenological stage. Results showed that cotton genotypes CNPA TB-90, BRS-293 and Delta Opal all produced higher levels of DMNT and TMTT at the vegetative stage than at the reproductive stage and that these homoterpenes allowed for principal component analysis separation of volatiles produced by the two phenological stages. Electroantennograms confirmed boll weevil antennal responses to DMNT and TMTT. Behavioral assays, using Y-tube olfactometers, showed that adding synthetic homoterpenes to reproductive cotton volatiles (mimicking cotton at the vegetative stage in terms of homoterpene levels) resulted in reduced attraction to boll weevils compared to that to unmodified reproductive cotton. Weevils showed no preference when given a choice between plants at the vegetative stage and the vegetative stage-mimicked plant. Altogether, the results show that DMNT and TMTT are used by boll weevils to distinguish between cotton phenological stages

ECONOMIC, ENVIRONMENTAL AND ENERGY USE IMPLICATIONS OF SHORT-SEASON COTTON PRODUCTION: TEXAS LOWER RIO GRANDE VALLEY

Crop Production/Industries,

Studies of fiber-matrix adhesion on compression strength

A study was initiated on the effect of the matrix polymer and the fiber matrix bond strength of carbon fiber polymer matrix composites. The work includes tests with micro-composites, single ply composites, laminates, and multi-axial loaded cylinders. The results obtained thus far indicate that weak fiber-matrix adhesion dramatically reduces 0 degree compression strength. Evidence is also presented that the flaws in the carbon fiber that govern compression strength differ from those that determine fiber tensile strength. Examination of post-failure damage in the single ply tests indicates kink banding at the crack tip

On the Lagrangian structure of 3D consistent systems of asymmetric quad-equations

Recently, the first-named author gave a classification of 3D consistent 6-tuples of quad-equations with the tetrahedron property; several novel asymmetric 6-tuples have been found. Due to 3D consistency, these 6-tuples can be extended to discrete integrable systems on Z^m. We establish Lagrangian structures and flip-invariance of the action functional for the class of discrete integrable systems involving equations for which some of the biquadratics are non-degenerate and some are degenerate. This class covers, among others, some of the above mentioned novel systems.Comment: 21 pp, pdfLaTe