Interior Rows Research Articles

Evaluating French marigold as a border insectary plant for the enhancement of beneficial arthropods in sweet corn plantings

Non-crop flora is often used on arable lands to augment beneficial arthropods in cropping systems. Though there may be an enhancement in the abundance of beneficials, this increase may be limited to crop borders or may not result in greater herbivore suppression. French marigold (Tagetes patula L.) was evaluated as an insectary plant for sweet corn (Zea mays L.) and compared with monoculture sweet corn plots. Several families of parasitoids and predators representing multiple taxa were attracted to marigold plants and more parasitoids were captured on sticky card traps located at the margins of sweet corn plots bordered by marigold as opposed to margins of sweet corn plots without marigold strips. Still, similar numbers of predators and/or parasitoids were found on sweet corn plants and/or card traps within the border and interior rows of sweet corn plots in both treatments. Furthermore, the percentage of sweet corn ears with herbivore feeding damage was similar in marigold diversified and monoculture sweet corn plots. Though marigold attracted some beneficial insects, it may not result in enhanced biological control of herbivorous pests in sweet corn plantings.

Spatial distribution of spotted-wing drosophila (Diptera: Drosophilidae) and other insects in fruit of a sweet cherry (Rosaceae) orchard

AbstractSpotted-wing drosophila, Drosophila suzukii (Matsumura) (Diptera: Drosophilidae), is an invasive pest of many small and soft fruits. We present the first results concerning its oviposition in the canopy of a sweet cherry (Prunus avium Linnaeus; Rosaceae) orchard. We examined the distribution of arthropods emerging from fruits of five cultivars ripening successively over seven weeks, in interior and border rows, within four regions of the tree canopy (top/bottom height × north/south aspect), and measured the associated fruit ripeness (ºBrix). Single fruits were reared for more than two weeks: 1328 arthropods emerged from 887 cherries in June, and 10 426 emerged from 1071 cherries in July. When populations were low, significantly more D. suzukii were present in the northernmost row and northern canopy aspect. Later, its distribution with respect to cherry row, height, and aspect was homogenous. Drosophila suzukii density per sweet cherry was highest in the latest ripening cultivar, when its distribution was not homogeneous; significantly more D. suzukii were in the centre than the southernmost row, in the lower canopy, and the southern aspect, than elsewhere. In the early season, single egg clutches were found without aggregation. As population density increased, so did intraspecific aggregation, but D. suzukii did not co-exist with other Drosophila Fallén species, nor with Rhagoletis indifferens Curran (Diptera: Tephritidae) when present.

Evaluating a push-pull tactic for management of Epilachna varivestis Mulsant and enhancement of beneficial arthropods in Phaseolus lunatus L.

Restoring ecological services in agroecosystems can compensate for the negative effects associated with agricultural intensification. For example, disruption of natural pest suppression can be mitigated through habitat manipulation to attract beneficial arthropods and alter colonization by herbivores. We evaluated a push-pull habitat manipulation system for its potential to suppress Mexican bean beetle (Epilachna varivestis Mulsant) and augment natural enemies in lima bean (Phaseolus lunatus L.). The push-pull treatment consisted of P. lunatus interplanted with French marigold (Tagetes patula L.) and bordered by wax snap beans (P. vulgaris L.), and was compared with a P. lunatus monoculture. Greater numbers of E. varivestis and other herbivores were found in the push-pull border (P. vulgaris) relative to the monoculture border and interior rows of both habitat types. Abundances of chewing and piercing-sucking predators were greatest in the interior rows of the push-pull treatment, and parasitoids were more abundant in the interior compared to the border rows of the push-pull treatment. However, while Pediobius spp. parasitoid wasps [Pediobius foveolatus (Crawford) attacks immature stages of E. varivestis] were also more abundant in the push-pull than monoculture treatment, their abundance was higher in the border relative to interior rows. Phaseolus lunatus plant productivity was lower in push-pull compared to monoculture habitats. Although further refinement is necessary, this push-pull strategy shows promise for manipulating Phaseolus cropping systems to improve natural pest control.

Spotted Wing Drosophila Prefer Low Hanging Fruit: Insights into Foraging Behavior and Management Strategies

Spotted wing drosophila, Drosophila suzukii, is an invasive insect that attacks ripe, small fruit such as raspberries, blackberries and blueberries. Little is known about its foraging ecology and current trapping methods and monitoring systems are ineffective at commercial scales. In semi-field studies, we evaluated adult alightment and ovipositional preference within and among raspberry plants using sentinel Tangletrap-coated and clean raspberry fruit, respectively, positioned within the exterior and interior plant canopy at four different heights (60, 85, 110 and 135 cm from the base) and conducted in field cages using sexually mature adults. Alightment of adults on Tangle-trap-coated fruit indicated a preference for fruit positioned at lower heights and/or interior locations based on significantly greater numbers being captured on sentinel sticky-coated berries at the two lowest heights. Oviposition in clean raspberry fruit also yielded a similar pattern. In mark-release-recapture studies conducted in the field, spotted wing drosophila prefer sentinel sticky fruit positioned on exterior rows as they alighted on these berries in significantly greater numbers than fruit at in the central portion of the plot. Likewise, in field trials with wild fly populations, infestations were significantly greater in edge rows compared with interior rows. Collectively, our results suggest that monitoring and behaviorally based management strategies may be more effective if they target adults foraging in the lower canopy of small fruit plants located on the crop perimeter.

Evidence for Functional Groupings of Vibrissae across the Rodent Mystacial Pad.

During natural exploration, rats exhibit two particularly conspicuous vibrissal-mediated behaviors: they follow along walls, and “dab” their snouts on the ground at frequencies related to the whisking cycle. In general, the walls and ground may be located at any distance from, and at any orientation relative to, the rat’s head, which raises the question of how the rat might determine the position and orientation of these surfaces. Previous studies have compellingly demonstrated that rats can accurately determine the horizontal angle at which a vibrissa first touches an object, and we therefore asked whether this parameter could provide the rat with information about the pitch, distance, and yaw of a surface relative to its head. We used a three-dimensional model of the whisker array to construct mappings between the horizontal angle of contact of each vibrissa and every possible (pitch, distance, and yaw) configuration of the head relative to a flat surface. The mappings revealed striking differences in the patterns of contact for vibrissae in different regions of the array. The exterior (A, D, E) rows provide information about the relative pitch of the surface regardless of distance. The interior (B, C) rows provide distance cues regardless of head pitch. Yaw is linearly correlated with the difference between the number of right and left whiskers touching the surface. Compared to the long reaches that whiskers can make to the side and below the rat, the reachable distance in front of the rat’s nose is relatively small. We confirmed key predictions of these functional groupings in a behavioral experiment that monitored the contact patterns that the vibrissae made with a flat vertical surface. These results suggest that vibrissae in different regions of the array are not interchangeable sensors, but rather functionally grouped to acquire particular types of information about the environment.

Hunters, herders and hearths: interpreting new results from hearth row sites in Pasvik, Arctic Norway

The transition from hunting to reindeer herding has been a central topic in a number of archaeological works. Recently conducted archaeological investigation of two interior hearth row sites in Pasvik, Arctic Norway, have yielded new results that add significantly to the discussion. The sites are dated within the period 1000-1300 AD, and are unique within this corpus due to their rich bone assemblages. Among the species represented, reindeer is predominant (87 %), with fish (especially whitefish and pike) as the second most frequent category. Even sheep bones are present, and represent the earliest indisputable domesticate from any Sámi habitation site. A peculiar feature is the repeated spatial pattern in bone refuse disposal, showing a systematic and almost identical clustering at the two sites. Combining analyses of bone assemblages, artefacts and archaeological features, the paper discusses changes in settlement pattern, reindeer economies, and the organization of domestic space. The analyses provide new perspectives on early domestication as well as on the remarkable changes that took place among the Sámi societies in northern Fennoscandinavia during the Viking Age and early Medieval Period.

Natural outcrossing and isolation distance requirements in exserted stigma tomato (Solanum lycopersicum) seed production

Genetic purity is of utmost important in seed production of varieties and hybrids. Since exserted stigma tomato types are much prone to natural crossing the chances of genetic contamination is higher in seed production and the recommended isolation requirements for hybrid seed production is higher (200m for foundation seeds and 100m for certified seeds). Hence, studies were conducted at Indian Institute of Horticultural Research, Bangalore, during rabi season of three years, 2007 to 2010 with an objective of determining the extent of natural cross pollination in terms of genetic contamination and to optimize the minimum isolation distance requirements for maintaining genetic purity in seed production of exserted stigma (recessive) tomato. The natural out crossing, i.e. genetic contamination was within 2% (permissible genetic standards) at a minimum isolation of 50m in interior rows of seed plots (R2 and R3) and in all the three years of study. Hence, a safer minimum isolation of 50 m with border rows is sufficient for tomato seed production using exserted stigma Ex-3 as seed parent for obtaining seeds of permissible genetic purity standards (98 %) under IIHR, Bangalore conditions, which is lesser than the recommended isolation of 200m for foundation seeds and 100m for certified seeds in hybrid seed production of tomato.

Effects of planting design on planted seedlings and spontaneous vegetation 16 years after establishment of forest edges

In afforestation, studies of forest edges seldom span the effects of planting design and the self-designing capacities of spontaneous vegetation. This study revisited experimental forest edge sections 16 years after their establishment to assess the impact of five design elements on (1) horizontal and vertical edge structure, (2) growth of planted species and species groups, and (3) spontaneous establishment of woody vegetation. The design elements were: exposure to direct solar radiation; edge typology (shrub mixture, mixture of trees and shrubs, no edge planting); width of edge planting (5 or 10 m); species mixture principle (intimate mixtures or single species grouping); and planting row position from outermost to interior planting row (max. 6 rows). The results demonstrate that edge plantings support significantly more spontaneous woody vegetation than stand boundaries without such edge plantings. This result was consistent across the different design elements. Position across the planting rows from the outermost to innermost row was the most influential design element for the development of planted seedlings. Planted tree and shrub species of similar shade tolerance had contradicting development, where light-demanding pioneer tree species had obtained dominant positions while shade-tolerant shrub species had outgrown more light-demanding species. These results demonstrate that important successional processes can be activated by establishing the initial components and structures of forest edges. When designing such edges, species should preferably be allocated to different row cohorts reflecting their growth form and shade tolerance.

EFFECTS OF THINNING ON TRANSPIRATION BY RIPARIAN BUFFER TREES IN RESPONSE TO ADVECTION AND SOLAR RADIATION

EFFECTS OF THINNING ON TRANSPIRATION BY RIPARIAN BUFFER TREES IN RESPONSE TO ADVECTION AND SOLAR RADIATION

Bonding and magnetism in nanosized graphene molecules: Singlet states of zigzag edged hexangulenes C6m2H6m(m=2,3,…,10)

A novel molecular phenomenon is predicted on the basis of trends identified in an ab initio density functional theory study of the electronic and geometric structure of the hexagonal shaped zigzag edged graphene hydrocarbon molecules C(6m(2) )H(6m)(m=2,...,10). Electrons in the interior organize to form a graphene core that grows with edge size m. Electrons in the highest occupied molecular orbital levels, localized primarily on the perimeter carbons, polarize the interior atoms with a intensity that decays rapidly with distance from the perimeter. Three distinctive bond length patterns emerge: (i) a central graphene core that grows with size m; (ii) shape-similar transverse and radial bond length patterns on interior rows close to the edges; and (iii) quinoidal bonds radiating from each apex that link adjacent edges. Concomitant with these changes are: (i) a monotonic decrease in atomic charge from center to perimeter and (ii) relegation of spin in diradical states to the outer atomic rows of the bipartite lattice.

Diplodia shoot blight and asymptomatic persistence of Diplodia pinea on or in stems of jack pine nursery seedlings

Summary Diplodia pinea (syn. Sphaeropsis sapinea) is known as a major cause of damage to red pine (Pinus resinosa) seedlings in nurseries. The fungus can also be a latent pathogen of red pine seedlings, persisting in the absence of gross symptoms and later proliferating under conditions that induce host stress. In the fall of 2004, three nurseries in Wisconsin were surveyed to determine the potential for the occurrence of Diplodia shoot blight on jack pine (Pinus banksiana) seedlings and the persistence of D. pinea on or in asymptomatic seedlings of this species. Incidence of shoot blight was quantified in five 1 m long segments of an interior row in each of two survey areas in each nursery. The pathogen was identified on symptomatic seedlings collected in these areas on the basis of presence of characteristic pycnidia and conidia. Five groups of 20 asymptomatic seedlings were also collected in each of the two survey areas in each nursery. A segment of the lower stem/root collar from each of these asymptomatic seedlings was surface‐disinfested and culturally assayed using tannic acid agar. The mean incidence of shoot blight (as high as 9%) and mean frequency of cultural detection from asymptomatic seedlings (as high as 20%) were greatest in proximity to red pine windbreaks which are a source of inoculum. Only D. pinea was confirmed from subsets of symptomatic and asymptomatic seedlings which were tested using mt SSU rDNA polymerase chain reaction (PCR) primers that allow differentiation of D. pinea from D. scrobiculata and other fungi in the genus Botryosphaeria and related anamorphic fungi. Jack pine seedlings inoculated with D. pinea isolates obtained from asymptomatic nursery seedlings developed shoot blight symptoms in greenhouse trials. Thus, the ability of D. pinea to damage jack pine seedlings in nurseries has been documented and the potential for virulent strains of this latent pathogen to be distributed on asymptomatic jack pine seedlings from nurseries has been confirmed.

Evidence for host plant preference by Iphiseiodes quadripilis (Acari: Phytoseiidae) on Citrus

In this study, we present field and laboratory evidence on the preference of Iphiseiodes quadripilis (Banks) for grapefruit (Citrus paradisi Macfadyen) leaves compared with sweet orange (Citrus sinensis (L.) Osbeck) leaves. This preference was confirmed in four orchards whether leaf samples were taken from either border trees of contiguous grapefruit or sweet orange or interior row trees with both citrus species in adjacent rows. Iphiseiodes quadripilis was most abundant in grapefruit trees in spite of the greater abundance of the Texas citrus mite, Eutetranychus banksi (McGregor) (Acari: Tetranychidae) in sweet orange trees. Similar preference responses were observed in laboratory tests using a Y-tube olfactometer whether I. quadripilis were collected from sweet orange or grapefruit. Iphiseiodes quadripilis collected from grapefruit trees showed significant preference for grapefruit over sweet orange leaves in contact choice tests using an arena of alternating leaf strips (12 mm long x 2 mm wide) of sweet orange and grapefruit. However, I. quadripilis collected from sweet orange trees did not show preference for either grapefruit or sweet orange leaves. Based on these results, grapefruit leaves foster some unknown factor or factors that retain I. quadripilis in greater numbers compared with sweet orange leaves.

Stall Usage Differences of Thirteen Different Freestall Base Types

The objective of this study was to compare percentages of cow preference measures for factors affecting use of stalls with different stall bases. Stall status was recorded four times each day in two pens with different stocking densities for a 6-mo period starting June 19, 2002. Six factors were analyzed: stall base, distance to water (WDIST), stall location within stall base section (STLLOC), stalls on interior or exterior row (RLOC), inside barn temperature, and length of time cows were exposed to stall bases (XPOSR). The 101% stocking density (SD) pen had eight different bases: two foam mattresses (FMATR), three rubber mattresses (RMATR), and three rubber mats (RMAT). The 66% SD pen had seven different stall bases, two identical to the first pen: a cork-filled mattress (CMATR), two FMATR, two RMATR, a waterbed, and a RMAT. Each pen was analyzed separately. Stall bases were grouped with 3 to 7 stalls per section and randomly placed in each row. In the 101% SD pen, FMATR and RMATR had the greatest lying and occupied percentages, and two RMAT had the least lying and occupied percentages. In the 66% SD pen, one FMATR and one RMATR had the greatest lying and occupied percentages, waterbeds were intermediate, and the CMATR, one RMATR, and a RMAT were inferior. Waterbeds were the stall base of choice during the coldest weather. In both pens, cows preferred the exterior (EXTR) row during evening and early morning. The addition of a foam layer increased use of mattresses and mats.

Competition for water in a pecan (Carya illinoensis K. Koch) – cotton (Gossypium hirsutum L.) alley cropping system in the southern United States

Understanding the belowground interactions between trees and crops is critical to successful management of agroforestry systems. In a study of competition for water in an alley cropping system consisting of pecan (Carya illinoensis) and cotton (Gossypium hirsutum) in a sandy loam soil (Rhodic Paleudult) in Jay, Florida, root systems of the two species were separated by trenching to 120 cm depth. A polyethylene barrier was installed in half of the plots. Spatial and temporal variations in soil water content, root distribution and water uptake by both species, and leaf area development and height of cotton were measured. Interspecific competition for water was greater in the non-barrier treatment near tree rows than at the alley center. Competition became evident 3 to 4 weeks after emergence of cotton and increased during the following 7 to 8 weeks. Compared with the non-barrier treatment, the barrier treatment had higher soil water content and better growth of cotton (height, leaf area, and fine root biomass). Cotton lint yield in the barrier treatment (677 kg ha–1) was similar to that in a sole-crop stand, but higher than in the non-barrier (502 kg ha–1) treatment. Lint production efficiency of plants was higher in the interior rows in the non-barrier treatment (0.197 kg lint per square meter of leaf area, compared to 0.117 kg in the barrier treatment). The results suggest that trenching or even deep disking parallel to the tree row may reduce competition for water, but the impact on tree growth cannot be established from this study.

9.1.9 Decision Metrics Matrix Process

AbstractThis paper presents a decision metric matrix process to evaluate the stakeholders needs related to their goal for improvement of a process, product or resources. The decision metric matrix gives the system engineer a method to name the components of the decision matrix and provides a process to extract, quantify and evaluate the metrics of the stakeholders' goals. Column one and subsequent rows of the decision matrix contain the decision parameters and the interior rows and columns contain the associated action statements and values. The stakeholder uses the action statements and action values as indicators to make a weighted decision concerning the goal. The decision metrics matrix uses concepts from the Goal‐Driven Measurement paradigm (Basili).

Movement of Corn Rootworm Larvae (Coleoptera: Chrysomelidae) Between Border Rows of Soybean and Corn in a Strip Intercropping System

Strip intercropping of corn may provide spatial and temporal diversity for management of extended-diapause corn rootworm populations. Strip-intercropped corn may sustain infestations of corn rootworm larvae attributable to migration of larvae into 1st-yr corn from soil previously planted to corn. Row-specific distribution of corn rootworm eggs and adult emergence were determined in a strip intercropped system, and effects of interstrip cultural and insecticidal treatments on rootworm infestation of outer rows were evaluated. Corn rootworm eggs were found in all rows of strips previously planted to corn. Root injury ratings were significantly higher in the outer rows than in the interior rows of corn adjacent to the previous year’s corn strips. Oilseed meal and insecticide treatments were associated with lower corn rootworm adult emergence and larval root injury than was found in untreated plots. Higher rootworm adult emergence and root injury scores in tillage treatments, where the soil was disturbed by ripping with a cultivator shank, were attributed to increased soil pore space that facilitated larval movement into adjacent corn strips. Fewer adults emerged and less root injury occurred in outer rows of corn adjacent to soybean strips that were subjected to interrow soil compaction from wheel traffic. In severely infested fields, deliberate compaction of interrow soil or incorporation of cruciferous plant material into soil between strips are possible noninsecticidal management options for reducing severe corn rootworm infestation of outside rows of corn in strip intercropping systems.

Yield and yield components of relay-intercropped wheat and soybean

Relay intercropping, where soybean [ Glycine max (L.) Merr.] is sown into standing wheat ( Triticum aestivum L.), alleviates several problems associated with delayed soybean sowings following wheat in a double-cropping system. However, relay intercropping has resulted in wheat yield reductions at some locations. Little information is available on the relative performance of wheat cultivars in this system or on the effect of wheat cultivar on performance of the soybean crop. This 2-y study compared performance of relay-intercropped versus sequentially double-cropped wheat and soybean and determined the influence of wheat cultivar on performance of wheat and the succeeding soybean crop. Three wheat cultivars were sown in a relay intercropping pattern (33-cm-wide rows with two 61-cm-wide traffic lanes per 11-row planter pass) and in a conventional double-cropping pattern (18-cm-wide rows). Intercropped soybean was sown between wheat rows 19 (1991) or 27 (1992) days before wheat harvest. Double-cropped soybean was sown in 97-cm rows after wheat harvest. Averaged over cultivars and years, intercropped wheat yield was 18% less than double-cropped wheat due to fewer spikes per unit area. No consistent cultivar by cropping system interaction occurred for wheat yield or yield components. The exception was that, in 1991, ‘Williams’ wheat had similar yields in both cropping systems, but its yields in both systems were very low. In the intercropped system, yields (on an area basis) were less in rows bordering traffic lanes than in interior rows. Double-cropped soybean plants were taller at harvest, but intercropped soybean had longer lower internodes and higher lodging scores. However, relay-intercropped and double-cropped soybean yields were similar, and independent of the previous wheat cultivar.

Microautoradiographic detection of CO2 fixation in lenticel chlorenchyma of youngFraxinus excelsior L. stems in early spring

Microautoradiography indicated that 1-year-oldFraxinus excelsior L. stem chlorenchyma assimilated external14CO2 in mid-April, when buds were swollen, but before bud-break. The lenticel regions showed the highest amount of radioactively labeled assimilates. Labeled assimilates declined in the tangential direction with increasing distance from lenticels, suggesting that14CO2 entered the stem through the open intercellular spaces of lenticels. In the radial direction, the amount of radioactively labeled assimilates did not constantly decline with growing distance from the lenticel entrance. It was high in all lenticel phelloderm cells, which had high chlorophyll autofluorescence and very small starch grains, highest in the adjacent 4–6 rows of chlorenchyma, which had larger starch grains that increased in size towards the interior rows, and much lower in the inner cortex chlorenchyma, which had large starch grains. We suggest that the main function of the lenticel chlorenchyma (lenticel phelloderm plus 4–6 rows of adjacent cortex chlorenchyma) is the refixation of respiratory CO2 which could easily leave the stem intercellular spaces, rather than the fixation of external CO2. The lenticel chlorenchyma could reduce the loss of respiratory CO2 by its photosynthetic activity.

Generalized Gaussian Birkhoff Quadrature Formulas

Existence of a generalized Gaussian Birkhoff quadrature formula is proved for a wide class of incidence matrices which satisfy the delayed Pólya conditions and contain no odd non-Hermitian sequences in the interior rows.

An improved model for solving the optimal placement for river-routing problem

Describes two linear-time river-routing algorithms for respectively optimizing and computing channel separation between the interior rows and columns of synthesized random-logic cells for custom module generation. The method uses river routing within the cells to virtually eliminate routing channels between the cell rows and columns while producing little or no increase in cell area. The first algorithm is a terminal-position assignment procedure that can be used in conjunction with the optimal-placement-for-river-routing algorithm given by C.E. Leiserson and R.Y. Pinter (see SIAM J. Computing, vol.12, no.3, p.447-462, 1983) to eliminate, or greatly reduce, the routing area that is computed by the second proposed algorithm. The second algorithm computes embedded river-routing channel separations between the rows and columns of cells. Use of these algorithms for optimizing the interconnections between custom-synthesized cells provides a significant improvement in area usage in comparison with using standard river routing methods. >