Inter-seasonal population dynamics and cultural management of Helicoverpa spp. in a Central Queensland cropping system

2001 ◽  
Vol 41 (2) ◽  
pp. 249 ◽  
Author(s):  
R. Sequeira
Keyword(s):  
Population Dynamics ◽  
Host Plant ◽  
Continuous Production ◽  
Cropping System ◽  
Cultural Control ◽  
Potential Contribution ◽  
Trap Crop ◽  
Trap Crops ◽  
Trap Cropping ◽  
The Impact

A strategic trap cropping program targeting Helicoverpa spp. on cotton was developed and implemented in the Emerald irrigation area of Central Queensland beginning in the winter of 1997. Growers were advised to plant 1% of total cropping area to a trap crop of chickpea (Cicer arietinum) in winter and pigeon pea (Cajanus cajan) in summer. The population dynamics of Helicoverpa spp. in relation to the Emerald cropping system was studied over a 3-year period (August 1996–July 1999) to provide a framework for testing the validity of key assumptions underlying the trap cropping strategy and optimising the implementation of the program. The population dynamics study showed continuous production of Helicoverpa pupae (moths) in the crop production system during each calendar year. The pattern of pupae production was consistent with cycling of Helicoverpa populations between irrigation and rainfed cropping components of the system. Spring rainfall and the availability of host plant resources is shown to impact on the population dynamics of Helicoverpa in the cropping system and its pest status on early-season cotton. Performance and potential impact of the trap crops are discussed within the context of host plant availability and resource bottlenecks. It is shown that the impact of the trap crops on abundance of Helicoverpa spp. early in the growing season could not be distinguished from that of naturally occurring host plant resource bottlenecks in spring most likely as a result of suboptimal timing of trap crop destruction. The potential contribution of cultural control tactics to integrated pest management of Helicoverpa spp. in cropping systems is discussed.

Evaluation of Trap Cropping for Control of Diamondback Moth (Lepidoptera: Plutellidae) in a Broccoli Production System

2020 ◽  
Vol 113 (4) ◽  
pp. 1864-1871
Author(s):  
S Sherbrooke ◽  
Y Carrière ◽  
J C Palumbo
Keyword(s):  
Plant Density ◽  
Cropping Systems ◽  
Larval Mortality ◽  
Diamondback Moth ◽  
Oviposition Preference ◽  
Indian Mustard ◽  
Trap Crop ◽  
Oviposition Choice ◽  
Trap Crops ◽  
Trap Cropping

Abstract Trap cropping, in which a trap crop is planted near a cash crop, has been used successfully for reducing pest damage in some agricultural systems. We used a meta-analysis of extensive data on two trap cropping systems, diamondback moth, Plutella xylostella (Linnaeus), exploiting cabbage and Chilo partellus (Swinhoe) (Lepidoptera: Crambidae) exploiting maize, to show that oviposition preference for, and high larval mortality on trap crops are important indicators of effectiveness of trap cropping systems. We then evaluated Indian mustard (Brassica juncea var. juncea L. Czern.) (Capparidales: Brassicaceae) and yellow rocket (Barbarea vulgaris W. T. Aiton) (Brassicales: Brassicaceae) as trap crops for protecting broccoli (Brassica oleracea var. italica Plenck) (Capparidales: Brassicaceae) against diamondback moth in Yuma, AZ, using planting configurations compatible with current practices for commercial production and without use of insecticides. In oviposition choice tests, both yellow rocket and Indian mustard were highly preferred over broccoli in the field. Furthermore, the number of larvae and pupae was significantly lower on yellow rocket and Indian mustard compared to broccoli, indicating relatively high mortality on these trap crops. Nevertheless, during the fall and spring growing seasons, no significant differences in the number of individuals on broccoli or proportion of broccoli crowns infested at harvest occurred between plots with trap crops relative to plots exclusively planted to broccoli. Thus, with the plant density and planting patterns used and without use of insecticides, there was no evidence that trap cropping was effective for reducing diamondback moth infestation of broccoli.

scholarly journals Major Lessons From Large-Scale Trap Cropping Demonstrations for Pest Reduction in Vegetables

2019 ◽  
Vol 112 (4) ◽  
pp. 298-301 ◽  
Author(s):  
Ayanava Majumdar ◽  
Matthew Price
Keyword(s):  
Large Scale ◽  
Insect Pests ◽  
Research Approach ◽  
Vegetable Production ◽  
Trap Crop ◽  
Trap Crops ◽  
Trap Cropping ◽  
Small Plot ◽  
Participatory Research Approach

Abstract Vegetable production in the Southeast is always at high risk from insect pests. Alternative integrated pest management (IPM) systems have to be effective in small plot as well as at the farming scale. This article explores the recent studies on large-scale trap crops using single or multiple cultivars and innovative layouts for long-term pest reduction. Trap crops must be planned carefully under high pest pressure and drought conditions along with an insecticide use strategy that minimizes external inputs and conserves natural enemies. Through participatory research approach, trap crop systems continue to evolve into practical solutions for the vegetable producers.

scholarly journals Evaluating legume species as alternative trap crops to chickpea for management of Helicoverpa spp. (Lepidoptera: Noctuidae) in central Queensland cotton cropping systems

2004 ◽  
Vol 94 (6) ◽  
pp. 481-486 ◽  
Author(s):  
P.R. Grundy ◽  
R.V. Sequeira ◽  
K.S. Short
Keyword(s):  
Cicer Arietinum ◽  
Cropping Systems ◽  
Field Pea ◽  
Cotton Production ◽  
Trap Crop ◽  
Production Region ◽  
Trap Crops ◽  
Trap Cropping ◽  
Blight Disease ◽  
High Level

AbstractMounting levels of insecticide resistance within Australian Helicoverpa spp. populations have resulted in the adoption of non-chemical IPM control practices such as trap cropping with chickpea, Cicer arietinum (L.). However, a new leaf blight disease affecting chickpea in Australia has the potential to limit its use as a trap crop. Therefore this paper evaluates the potential of a variety of winter-active legume crops for use as an alternative spring trap crop to chickpea as part of an effort to improve the area-wide management strategy for Helicoverpa spp. in central Queensland's cotton production region. The densities of Helicoverpa eggs and larvae were compared over three seasons on replicated plantings of chickpea, Cicer arietinum (L.), field pea Pisum sativum (L), vetch, Vicia sativa (L.) and faba bean, Vicia faba from the plants after oviposition. Plantings of field pea as a replacement trap crop for chickpea under commercial conditions confirmed the high level of attractiveness of this crop to ovipositing moths. The use of field pea as a trap crop as part of an area-wide management programme for Helicoverpa spp. is discussed.

scholarly journals The ‘Botanical Triad’: The Presence of Insectary Plants Enhances Natural Enemy Abundance on Trap Crop Plants in an Organic Cabbage Agro-Ecosystem

Insects ◽  
2019 ◽  
Vol 10 (6) ◽  
pp. 181
Author(s):  
Binita Shrestha ◽  
Deborah L. Finke ◽  
Jaime C. Piñero
Keyword(s):  
Brassica Oleracea ◽  
Natural Enemies ◽  
Trichoplusia Ni ◽  
Service Providers ◽  
Cropping System ◽  
Crop Plants ◽  
Trap Crop ◽  
Cash Crop ◽  
Trap Crops ◽  
Lobularia Maritima

Habitat manipulation through the incorporation of non-crop plants such as trap crops (to lure pests away from the cash crop) and insectary plants (to provide resources for natural enemies) into agro-ecosystems is an ecological approach to pest management. In a field-scale study, we quantified the effects of integrating the use of trap crops with insectary plants as a novel method to control pest herbivores in an organic cabbage agro-ecosystem. We hypothesized that pests would be concentrated in the trap crop habitat and suppressed by insectary-subsidized natural enemies in situ. We documented arthropod abundance (both adults and immature stages) associated with (1) two insectary plant species (sweet alyssum, Lobularia maritima, and buckwheat, Fagopyrum esculentum) either alone or in combination; (2) a trap crop mixture of mighty mustard (Brassica juncea), red Russian kale (Brassica oleracea var. acephala), and glossy collards (Brassica oleracea var. italica), and (3) cabbage cash crop (Brassica oleracea var. capitata). Trap crops were more attractive to pests than the cash crop. On a per-plant basis, densities of the herbivores Evergestis rimosalis, Trichoplusia ni, and Plutella xylostella were 154, 37, and 161× greater on the kale trap crop than on the cabbage cash crop, and 54, 18, and 89× greater on the collards trap crop than on the cash crop. Insectary plants contributed to the consumption of pests that aggregated on the trap crop. Parasitism of E. rimosalis by the braconid wasp Cotesia orobenae was significantly increased, and the abundance of eggs and larvae of the predatory coccinellid beetle Coleomegilla maculata was greater on the trap crop in the presence of insectary plants compared to trap crops that lacked insectary plants. The ‘Botanical Triad’ of cash crop, trap crop, and insectary plants represents a new type of agro-ecosystem manipulation that integrates ecosystem service providers (e.g., predators and parasitoids) within the cropping system.

Long-term population dynamics of the red deer and European roe deer at the protected and not-protected areas in Mountain Crimea

2017 ◽  
Vol 7 (4) ◽  
pp. 65-72
Author(s):  
V. N. Shmagol' ◽  
V. L. Yarysh ◽  
S. P. Ivanov ◽  
V. I. Maltsev
Keyword(s):  
Population Dynamics ◽  
Protected Areas ◽  
Red Deer ◽  
Nature Reserve ◽  
Roe Deer ◽  
Precipitation Amount ◽  
Annual Precipitation ◽  
Population Number ◽  
The Impact

<p>The long-term population dynamics of the red deer (<em>Cervus elaphus</em> L.) and European roe deer (<em>Capreolus</em> <em>capreolus</em> L.) at the mountain and forest zone of Crimea during 1980-2017 is presented. Fluctuations in numbers of both species are cyclical and partly synchronous. Period of oscillations in the population of red deer is about 25 years, the average duration of the oscillation period of number of roe deer is 12.3 years. During the fluctuations in the number the increasing and fall in population number of the red deer had been as 26-47 %, and roe deer – as 22-34 %. Basing on the dada obtained we have assumed that together with large-scale cycles of fluctuations in population number of both red deer and roe deer the short cycles of fluctuations in the number of these species with period from 3.5 to 7.5 years take place. Significant differences of the parameters of cyclical fluctuations in the number of roe deer at some sites of the Mountainous Crimea: breaches of synchronicity, as well as significant differences in the duration of cycles are revealed. The greatest deviations from the average values of parameters of long-term dynamics of the number of roe deer in Crimea are noted for groups of this species at two protected areas. At the Crimean Nature Reserve the cycle time of fluctuations of the numbers of roe deer was 18 years. At the Karadag Nature Reserve since 1976 we can see an exponential growth in number of roe deer that is continued up to the present time. By 2016 the number of roe deer reached 750 individuals at a density of 437 animals per 1 thousand ha. Peculiarity of dynamics of number of roe deer at some sites proves the existence in the mountain forest of Crimea several relatively isolated groups of deer. We assumed that "island" location of the Crimean populations of red deer and European roe deer, their relatively little number and influence of permanent extreme factors of both natural and anthropogenic origination have contributed to a mechanism of survival of these populations. The elements of such a mechanism include the following features of long-term dynamics of the population: the reduction in the period of cyclic population fluctuations, while maintaining their amplitude and the appearance of additional small cycles, providing more flexible response of the population to the impact of both negative and positive environmental factors. From the totality of the weather conditions for the Crimean population of roe deer the recurring periods of increases and downs in the annual precipitation amount may have relevance. There was a trend of increase in the roe deer population during periods of increasing annual precipitation.</p>

Population dynamics driven by truncated stable processes with Markovian switching

2021 ◽  
Vol 58 (2) ◽  
pp. 505-522
Author(s):  
Zhenzhong Zhang ◽  
Jinying Tong ◽  
Qingting Meng ◽  
You Liang
Keyword(s):  
Population Dynamics ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Markovian Switching ◽  
Stable Processes ◽  
Necessary And Sufficient ◽  
The Impact

AbstractWe focus on the population dynamics driven by two classes of truncated $\alpha$-stable processes with Markovian switching. Almost necessary and sufficient conditions for the ergodicity of the proposed models are provided. Also, these results illustrate the impact on ergodicity and extinct conditions as the parameter $\alpha$ tends to 2.

scholarly journals Parasitism of Aedes albopictus by Ascogregarina taiwanensis lowers its competitive ability against Aedes triseriatus

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Emma Stump ◽  
Lauren M. Childs ◽  
Melody Walker
Keyword(s):  
Population Dynamics ◽  
Competitive Advantage ◽  
Aedes Albopictus ◽  
Abiotic Factors ◽  
Mosquito Species ◽  
Disease Spread ◽  
Aedes Triseriatus ◽  
La Crosse Virus ◽  
The Impact ◽  
Ascogregarina Taiwanensis

Abstract Background Mosquitoes are vectors for diseases such as dengue, malaria and La Crosse virus that significantly impact the human population. When multiple mosquito species are present, the competition between species may alter population dynamics as well as disease spread. Two mosquito species, Aedes albopictus and Aedes triseriatus, both inhabit areas where La Crosse virus is found. Infection of Aedes albopictus by the parasite Ascogregarina taiwanensis and Aedes triseriatus by the parasite Ascogregarina barretti can decrease a mosquito’s fitness, respectively. In particular, the decrease in fitness of Aedes albopictus occurs through the impact of Ascogregarina taiwanensis on female fecundity, larval development rate, and larval mortality and may impact its initial competitive advantage over Aedes triseriatus during invasion. Methods We examine the effects of parasitism of gregarine parasites on Aedes albopictus and triseriatus population dynamics and competition with a focus on when Aedes albopictus is new to an area. We build a compartmental model including competition between Aedes albopictus and triseriatus while under parasitism of the gregarine parasites. Using parameters based on the literature, we simulate the dynamics and analyze the equilibrium population proportion of the two species. We consider the presence of both parasites and potential dilution effects. Results We show that increased levels of parasitism in Aedes albopictus will decrease the initial competitive advantage of the species over Aedes triseriatus and increase the survivorship of Aedes triseriatus. We find Aedes albopictus is better able to invade when there is more extreme parasitism of Aedes triseriatus. Furthermore, although the transient dynamics differ, dilution of the parasite density through uptake by both species does not alter the equilibrium population sizes of either species. Conclusions Mosquito population dynamics are affected by many factors, such as abiotic factors (e.g. temperature and humidity) and competition between mosquito species. This is especially true when multiple mosquito species are vying to live in the same area. Knowledge of how population dynamics are affected by gregarine parasites among competing species can inform future mosquito control efforts and help prevent the spread of vector-borne disease.

scholarly journals A Cross-Metabolomic Approach Shows that Wheat Interferes with Fluorescent Pseudomonas Physiology through Its Root Metabolites

Metabolites ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 84
Author(s):  
Laura Rieusset ◽  
Marjolaine Rey ◽  
Florence Gerin ◽  
Florence Wisniewski-Dyé ◽  
Claire Prigent-Combaret ◽  
...  
Keyword(s):  
Secondary Metabolites ◽  
Host Plant ◽  
Soil Microorganisms ◽  
Wheat Root ◽  
Bioactive Metabolites ◽  
Root Extracts ◽  
Fluorescent Pseudomonas ◽  
Health And Development ◽  
The Impact ◽  
Metabolomic Approach

Roots contain a wide variety of secondary metabolites. Some of them are exudated in the rhizosphere, where they are able to attract and/or control a large diversity of microbial species. In return, the rhizomicrobiota can promote plant health and development. Some rhizobacteria belonging to the Pseudomonas genus are known to produce a wide diversity of secondary metabolites that can exert a biological activity on the host plant and on other soil microorganisms. Nevertheless, the impact of the host plant on the production of bioactive metabolites by Pseudomonas is still poorly understood. To characterize the impact of plants on the secondary metabolism of Pseudomonas, a cross-metabolomic approach has been developed. Five different fluorescent Pseudomonas strains were thus cultivated in the presence of a low concentration of wheat root extracts recovered from three wheat genotypes. Analysis of our metabolomic workflow revealed that the production of several Pseudomonas secondary metabolites was significantly modulated when bacteria were cultivated with root extracts, including metabolites involved in plant-beneficial properties.

scholarly journals The influence of density in population dynamics with strong and weak Allee effect

2021 ◽  
Vol 29 (1) ◽  
Author(s):  
Kamrun Nahar Keya ◽  
Md. Kamrujjaman ◽  
Md. Shafiqul Islam
Keyword(s):  
Population Dynamics ◽  
Allee Effect ◽  
Global Bifurcation ◽  
Reaction Diffusion ◽  
Logistic Growth ◽  
Allee Effects ◽  
Reaction Diffusion Model ◽  
Positive Steady States ◽  
The Stability ◽  
The Impact

AbstractIn this paper, we consider a reaction–diffusion model in population dynamics and study the impact of different types of Allee effects with logistic growth in the heterogeneous closed region. For strong Allee effects, usually, species unconditionally die out and an extinction-survival situation occurs when the effect is weak according to the resource and sparse functions. In particular, we study the impact of the multiplicative Allee effect in classical diffusion when the sparsity is either positive or negative. Negative sparsity implies a weak Allee effect, and the population survives in some domain and diverges otherwise. Positive sparsity gives a strong Allee effect, and the population extinct without any condition. The influence of Allee effects on the existence and persistence of positive steady states as well as global bifurcation diagrams is presented. The method of sub-super solutions is used for analyzing equations. The stability conditions and the region of positive solutions (multiple solutions may exist) are presented. When the diffusion is absent, we consider the model with and without harvesting, which are initial value problems (IVPs) and study the local stability analysis and present bifurcation analysis. We present a number of numerical examples to verify analytical results.

scholarly journals Genomic imbalances in the placenta are associated with poor fetal growth

2021 ◽  
Vol 27 (1) ◽  
Author(s):  
Giulia F. Del Gobbo ◽  
Yue Yin ◽  
Sanaa Choufani ◽  
Emma A. Butcher ◽  
John Wei ◽  
...  
Keyword(s):  
Fetal Growth ◽  
Sex Chromosome ◽  
Copy Number Variants ◽  
Placental Insufficiency ◽  
Potential Contribution ◽  
Genomic Imbalances ◽  
Significant Difference ◽  
Underlying Causes ◽  
Risk Of Disease ◽  
The Impact

Abstract Background Fetal growth restriction (FGR) is associated with increased risks for complications before, during, and after birth, in addition to risk of disease through to adulthood. Although placental insufficiency, failure to supply the fetus with adequate nutrients, underlies most cases of FGR, its causes are diverse and not fully understood. One of the few diagnosable causes of placental insufficiency in ongoing pregnancies is the presence of large chromosomal imbalances such as trisomy confined to the placenta; however, the impact of smaller copy number variants (CNVs) has not yet been adequately addressed. In this study, we confirm the importance of placental aneuploidy, and assess the potential contribution of CNVs to fetal growth. Methods We used molecular-cytogenetic approaches to identify aneuploidy in placentas from 101 infants born small-for-gestational age (SGA), typically used as a surrogate for FGR, and from 173 non-SGA controls from uncomplicated pregnancies. We confirmed aneuploidies and assessed mosaicism by microsatellite genotyping. We then profiled CNVs using high-resolution microarrays in a subset of 53 SGA and 61 control euploid placentas, and compared the load, impact, gene enrichment and clinical relevance of CNVs between groups. Candidate CNVs were confirmed using quantitative PCR. Results Aneuploidy was over tenfold more frequent in SGA-associated placentas compared to controls (11.9% vs. 1.1%; p = 0.0002, OR = 11.4, 95% CI 2.5–107.4), was confined to the placenta, and typically involved autosomes, whereas only sex chromosome abnormalities were observed in controls. We found no significant difference in CNV load or number of placental-expressed or imprinted genes in CNVs between SGA and controls, however, a rare and likely clinically-relevant germline CNV was identified in 5.7% of SGA cases. These CNVs involved candidate genes INHBB, HSD11B2, CTCF, and CSMD3. Conclusions We conclude that placental genomic imbalances at the cytogenetic and submicroscopic level may underlie up to ~ 18% of SGA cases in our population. This work contributes to the understanding of the underlying causes of placental insufficiency and FGR, which is important for counselling and prediction of long term outcomes for affected cases.

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