Relationship Between Weed Communities in Corn and Infestation and Damage by the Stalk Borer (Lepidoptera: Noctuidae)

1991 ◽  
Vol 26 (2) ◽  
pp. 253-260 ◽  
Author(s):  
Daniel M. Pavuk ◽  
Benjamin R. Stinner
Keyword(s):  
Larval Survival ◽  
Severe Drought ◽  
Corn Plant ◽  
Stalk Borer ◽  
Weed Communities ◽  
Corn Fields ◽  
Corn Plants ◽  
The Relationship ◽  
Lepidoptera Noctuidae

During 1988 and 1989, the relationship between different weed communities in corn plantings and infestation of and damage to corn by the stalk borer, Papaipema nebris (Guenée) (Lepidoptera: Noctuidae), was studied in Ohio. The four treatments were corn without weeds, corn principally with broadleaf weeds, corn principally with grasses, and corn with a mixture of both weed types. In 1988, there were no significant differences between treatments with broadleaf weeds and treatments without broadleaf weeds, and between treatments with grassy weeds and treatments without grassy weeds, in terms of number of larvae per corn plant and number of corn plants damaged. Low populations of P. nebris in corn during 1988 may have been associated with severe drought which caused low larval survival. There were significantly more larvae per corn plant and a significantly greater percentage of corn plants damaged in plantings containing broadleaf weeds than in corn plantings without broadleaf weeds in 1989. The results of this study show that the presence of broadleaf weeds in corn fields may lead to increased infestation of corn by stalk borer larvae.

scholarly journals PERKEMBANGAN Spodoptera frugiperda J.E Smith PADA TANAMAN JAGUNG MANIS (Zea mays L. Saccharata)

2021 ◽  
Vol 6 (2) ◽  
pp. 104
Author(s):  
Wilyus Wilyus ◽  
Hamdan Maruli Siregar ◽  
Rizki Aulia
Keyword(s):  
Spodoptera Frugiperda ◽  
Zea Mays L ◽  
Sweet Corn ◽  
Population Development ◽  
Corn Plant ◽  
Plant Parts ◽  
Plant Pests ◽  
Corn Plants ◽  
The Right ◽  
The Relationship

This study was conducted to determine the relationship between sweet corn plant phenology and population development and the attack of Spodoptera frugiperda. The research was carried out at the Research Farm and at the Laboratory of Plant Pests, Faculty of Agriculture, Jambi University. The study was conducted on an area of 500 m2 containing 28 plant plots. The sample plants consisted of 4 plots determined systematically. In each sample plot, all plants were used as sample.  plants to calculate the percentage of attacked plants, and the percentage of attacked cobs. S. frugiperda population observations were carried out directly on leaves, stems, flowers and cobs. If there were S. frugiperda faeces on the shoots, stems, and cobs, destructive observations were made where the plant parts were opened, to determine the presence of S. frugiperda in them. The data obtained were tabulated and arranged in the form of tables and figures, then explained descriptively. The results showed that: the population of S. frugiperda in each growth phase continued to increase, the highest population of S. frugiperda was found in the R6 phase or in the physiological ripening phase, which was as many as 21 heads per 12 corn plants; the percentage of attacks of S. frugiperda in each phase continues to increase, the highest percentage of attacks is in phase R6, which is 78.72%;  the attack of S. frugiperda on cobs began to be seen in the R2-R5 phase and was highest in the R6 phase, which was 68.57%. It is necessary to find the right way to control S. frugiferda.

DISTRIBUTION OF THE STALK BORER PAPAIPEMA NEBRIS (LEPIDOPTERA: NOCTUIDAE) IN NO-TILL CORN

1989 ◽  
Vol 24 (4) ◽  
pp. 428-436
Author(s):  
H. Brett Highland ◽  
James E. Roberts
Keyword(s):  
Sample Size ◽  
Plant Species ◽  
Tall Fescue ◽  
Field Margins ◽  
Stalk Borer ◽  
No Till ◽  
The Mean ◽  
Corn Fields ◽  
Mean Variance ◽  
Lepidoptera Noctuidae

Significantly higher numbers of stalk borer (SB) Papaipema nebris (Guenée) larvae infested no-till corn seedlings were found adjacent to (ie. ca 4 m) field margins, compared to numbers found 30 meters from field margins. Plant species abundant in the areas surrounding SB infested no-till corn fields in southwestern Virginia included tall fescue, Fescuta arundinacea Schreb., and orchardgrass, Dactylus glomerata L. Contour and transect maps of infested fields from 1983 to 1985 suggested SB distribution to be clumped. This distribution was confirmed by high variance to mean ratios of 7.3, 5.8, 12.4, and 9.4 for 1983, 1984, 1985a and 1985b fields, respectively. Green's coefficient of dispersion and Morisita's coefficient of dispersion showed clumping of the SB independent of the mean, variance, and sample size. This is the first documentation that the SB infests fields predominantly on field borders, and the first quantification of the distribution of the SB in no-till corn.

EFFECT OF SPACING AND CLUMPING OF CORN PLANTS ON DENSITY OF CORN-ROOTWORM LARVAE (COLEOPTERA: CHRYSOMELIDAE) PER ROOT SYSTEM

1985 ◽  
Vol 117 (2) ◽  
pp. 139-142 ◽  
Author(s):  
Olga Piedrahita ◽  
C. R. Ellis ◽  
O. B. Allen
Keyword(s):  
Relative Density ◽  
Root System ◽  
Corn Rootworm ◽  
Plant Spacing ◽  
Corn Rootworms ◽  
Corn Plants ◽  
The Relationship ◽  
Field Plots

AbstractThe relative density of corn-rootworm larvae was estimated in two field plots with 4 different plant spacings and with up to 4 plants clumped per location. In both fields the relationship between plant spacing and the number of corn rootworms per sample was similar with the maximum number of larvae occurring when plants were 46 or 50 cm apart. The number of plants clumped per location affected the numbers of corn rootworm in only one field. The relationship between clumping of plants and number of corn rootworms was curvilinear in this field with the most corn rootworms occurring at 3 plants per location.

scholarly journals Within-Tree Distribution and Survival of the Eucalyptus Longhorned Borer Phoracantha semipunctata (Coleoptera: Cerambycidae) in a Mediterranean-Type Ecosystem

Insects ◽  
2020 ◽  
Vol 11 (4) ◽  
pp. 225
Author(s):  
Stephen Seaton ◽  
George Matusick ◽  
Giles Hardy
Keyword(s):  
Larval Development ◽  
Larval Survival ◽  
Severe Drought ◽  
Eucalyptus Marginata ◽  
Phoracantha Semipunctata ◽  
Tree Distribution ◽  
Eucalypt Forest ◽  
Attack Patterns ◽  
Mediterranean Type Ecosystem ◽  
Tree Characteristics

The attack patterns, infestation success and larval development of woodborers within living trees are complex and are largely shaped by host tree characteristics. Following a severe drought in a native eucalypt forest where outbreak densities of a native Australian beetle, the eucalyptus longhorned borer (Phoracantha semipunctata), occurred, a tree dissection study was conducted in Australia. This involved felling 40 trees each of jarrah (Eucalyptus marginata) and marri (Corymbia calophylla) that were cut into 1-m sections and neonate larval galleries, larvae in pupal cells and adult borer emergence were measured and added to give total numbers per tree to determine the within-tree distribution and survival of P. semipunctata. There was a significant impact on larval survival in both species, in contrast, pupal survival remained high. Within-tree distribution of P. semipunctata was directional with borer emergence and incidence of larval galleries both negatively associated with tree section height above the ground and positively associated with section diameter and bark thickness, reaching a maximum towards the base of trees. High incidence and survival in lower thicker tree sections indicate a more conducive environment for larval development, in contrast to poor larval survival in smaller thinner sections at the top of trees. The dependence of larval survival on tree characteristics controlling the within-tree distribution of borer emergence is emphasized, and needs to be considered when estimating the spread of borer populations during outbreaks.

scholarly journals Biodiversity of Segetal Weed Communities when Chlorsulfuron-Based Weed Control is Being Used on Continuous Winter Wheat

2014 ◽  
Vol 54 (3) ◽  
pp. 300-305
Author(s):  
Zbigniew Pawlonka ◽  
Katarzyna Rymuza ◽  
Krzysztof Starczewski ◽  
Antoni Bombik
Keyword(s):  
Winter Wheat ◽  
Initial Study ◽  
Short Term ◽  
Weed Communities ◽  
The Status ◽  
Weed Infestation ◽  
Weedy Species ◽  
The Relationship ◽  
Experimental Plots ◽  
Segetal Communities

Abstract The purpose of the study was to determine the relationship between herbicide rate and weed community biodiversity in continuous wheat. A six-year field experiment was conducted to examine the effect of four chlorsulfuron rates in comparison with untreated (the control) plots, on the status and severity of weed infestation - in successive study years of cultivating winter wheat in monoculture. In addition, the following indices were calculated: Shannon-Wiener and Simpson’s index of biodiversity, and Simpson’s index of domination. A total of 36 weedy species were identified in the experimental plots. The richest segetal communities were established in the control plots. An application of herbicide reduced the biodiversity of the agrophytocensosis. A short-term monoculture did not impoverish the species richness of the weed community established in winter wheat. The average number of species in the community was significantly greater in the second study year. In the initial study years of monoculture, the biodiversity of the segetal community increased markedly compared with rotation-based cultivation. The calculated indices of biodiversity were not significantly affected by herbicide rate or monoculture but the indices confirmed the trends outlined by an analysis of the status and level of weed infestation.

Effects of Weed Control Methods on Sweet Corn

Weed Science ◽  
1970 ◽  
Vol 18 (6) ◽  
pp. 707-711 ◽  
Author(s):  
L. L. Danielson
Keyword(s):  
Sweet Corn ◽  
Root Zone ◽  
Soil Surface ◽  
Root Systems ◽  
Severe Drought ◽  
Silt Loam ◽  
Control Methods ◽  
Herbicide Treatments ◽  
Drought Conditions ◽  
Corn Plants

Three tractor cultivations that severely pruned the root systems of hand-weeded plots of sweet corn [Zea mays L. var. rugosa Bonaf., Iochief] grown on a Codorus-Elkton silt loam under extreme drought conditions did not reduce the yield of marketable ears when irrigation totalling 2 acre-inches was applied during pollination and ear-filling. Pre-emergence application of 2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine [atrazine] to the soil surface without cultivation reduced brace root growth and yields significantly in the year of most severe drought. These effects of atrazine were avoided when the herbicide treatments were supplemented with tractor cultivations that covered the brace root zone of the corn plants with soil.

scholarly journals Estimate of Alabama argillacea (Hübner) (Lepidoptera: Noctuidae) development with nonlinear models

2003 ◽  
Vol 63 (4) ◽  
pp. 589-598 ◽  
Author(s):  
R. S. Medeiros ◽  
F. S. Ramalho ◽  
J. C. Zanuncio ◽  
J. E. Serrão
Keyword(s):  
Relative Humidity ◽  
Gossypium Hirsutum ◽  
Nonlinear Model ◽  
Nonlinear Models ◽  
Gossypium Hirsutum L ◽  
Developmental Rates ◽  
Alabama Argillacea ◽  
The Relationship ◽  
Lepidoptera Noctuidae

The objective of this work was to evaluate which nonlinear model [Davidson (1942, 1944), Stinner et al. (1974), Sharpe & DeMichele (1977), and Lactin et al. (1995)] best describes the relationship between developmental rates of the different instars and stages of Alabama argillacea (Hübner) (Lepidoptera: Noctuidae), and temperature. A. argillacea larvae were fed with cotton leaves (Gossypium hirsutum L., race latifolium Hutch., cultivar CNPA 7H) at constant temperatures of 20, 23, 25, 28, 30, 33, and 35ºC; relative humidity of 60 ± 10%; and photoperiod of 14:10 L:D. Low R² values obtained with Davidson (0.0001 to 0.1179) and Stinner et al. (0.0099 to 0.8296) models indicated a poor fit of their data for A. argillacea. However, high R² values of Sharpe & DeMichele (0.9677 to 0.9997) and Lactin et al. (0.9684 to 0.9997) models indicated a better fit for estimating A. argillacea development.

scholarly journals Research on Occurrence and Development of Pasture Drought Events in Alpine Grassland using the Drought Threshold

2018 ◽  
Author(s):  
Tiaofeng Zhang ◽  
Lin Li ◽  
Hongbin Xiao ◽  
Hongmei Li
Keyword(s):  
Soil Moisture ◽  
Alpine Grassland ◽  
Soil Drought ◽  
Severe Drought ◽  
Drought Event ◽  
Drought Intensity ◽  
Quantitative Expression ◽  
Initial Soil Moisture ◽  
Initial Soil ◽  
The Relationship

Abstract. Pasture is vital to livestock husbandry development in Qinghai and even in North China. Drought is the primary meteorological disaster that affects pasture, but insufficient soil moisture is the most prominent cause of pasture drought. Timely and accurate determination of the soil moisture threshold of pasture is important for objective recognition and monitoring of the occurrence and development of pasture drought. This study aims at investigating pasture responses to soil drought as well as quantitative expression of soil drought degree and drought threshold. Test plots were selected from the pasture test station. Five testing groups were set according to coverage rate (0–100 %) at the initiation the pasture growth period. The impacts of profile moisture characteristics, drought threshold, and precipitation on duration of pasture drought were studied. Research results have demonstrated that moisture in the soil profile below 20 cm decreases slightly throughout drought events in alpine grassland. Changes of soil moisture in the 0–20 cm layer can generally reflect drought stress of the pasture. In the process of a drought event, the relationship between soil water storage and cumulative relative water loss can be expressed via a logarithmic linear equation. Quantitative expression of drought degree in grasslands can be realized by transforming the slope of this equation into the index D with an interval of [0, 1]. The occurrence rates of mild drought,moderate drought, and severe drought were 0.36, 0.45, and 0.70, respectively. The duration of severe drought was closely related with initial soil moisture. The relationship between duration of drought and the necessary minimum precipitation can be expressed by an exponential equation. Values of the D index can express soil drought intensity and pasture drought intensity. The durations for different grades of drought events were correlated with both initial soil moisture and previous precipitation. The conclusions of this study can provide scientific references for the objective understanding onoccurrence, development, monitoring, and early warning of pasture drought.

Sign in / Sign up

Export Citation Format

Share Document