The effects of natural enemies, competition, and host plant water availability on an aphid population

Oecologia ◽  
1992 ◽  
Vol 90 (3) ◽  
pp. 359-365 ◽  
Author(s):  
William F. Morris
2019 ◽  
Vol 25 (1) ◽  
Author(s):  
NARENDRA SINGH ◽  
N. S. BHADAURIA ◽  
PRADYUMN SINGH

The Bio-efficacy of eleven plant extracts namely viz.Neem Kernel; Rhizome of Ginger; Leaves of Datura, Gajarghas, Harsingar, Oak and Latjeera; Bulb of Garlic and Onion; Flowers of Chrysenthemum and Fruits of Chilli in the concentration of 5 percent and imidacloprid @ 40 g ai/ha was tested against mustard aphid, Lipaphiserysimi and their effect on D. rapae and Coccinellid beetle were tested in the Department of Entomology, College of Agriculture, Gwalior (M.P.). All the tested plant materials and imidacloprid @ 40 g ai/ha were effective significanty in reducing the aphid population over control.The aphid population in treated plots ranged from 7.2 to 40.0 as against 85.4 aphid/twig in untreated control. Among the plant material, three sprays of Neem Kernel were found most effective followed by three sprays of chilli fruits.All the plant extracts were found significantly safer to D. rapae and coccinellid bettle in comparision to insecticide (imidacloprid).


2015 ◽  
Vol 8 (3) ◽  
pp. 1275-1283 ◽  
Author(s):  
G. Doury ◽  
J. Pottier ◽  
A. Ameline ◽  
A. Mennerat ◽  
F. Dubois ◽  
...  

Zootaxa ◽  
2012 ◽  
Vol 3423 (1) ◽  
pp. 45 ◽  
Author(s):  
SERGIO ANTONIO VANIN ◽  
DANIELA DE CASSIA BENÁ ◽  
FABIANO FABIAN ALBERTONI

Immatures of the Phelypera schuppeli (Boheman, 1834) (Curculionidae; Hyperinae; Cepurini) are described, illustrated and compared with available descriptions of larvae and pupae of Hyperini. Immatures and adults from midwest (Dourados, Mato Grosso do Sul; Pirenópolis, Goiás) and southeast Brazil (Bauru, São Paulo) were found on leaves of the host plant, Pachira aquatica Aubl. ( Malvaceae, formerly Bombacaceae), a tree used as an ornamental plant in many Brazilian frost-free cities. Larvae of P. schuppeli are exophytic, brightly colored, eruciform and possess abdominal ambulatory ampullae, resembling larvae of Lepidoptera. Mature larvae can spin globular lattice-like cocoons where pupation takes place. Data in the field and under laboratory conditions confirmed previously published biological observations on P. schuppeli. Additional information about defensive behaviors, process of cocoon construction and natural enemies, such as the larval predator Supputius cinticeps (Stål, 1860) (Hemiptera: Pentatomidae) and the prepupal and pupal parasitoid Jaliscoa nudipennis Bouček, 1993 (Hymenoptera: Pteromalidae), are reported.


2019 ◽  
Vol 112 (4) ◽  
pp. 1587-1597 ◽  
Author(s):  
Juan Pedro Raul Bouvet ◽  
Alberto Urbaneja ◽  
César Monzó

Abstract The Spirea citrus aphid, Aphis spiraecola Patch, and the cotton aphid, Aphis gossypii Glover (Hemiptera: Aphididae), are key pests of clementine mandarines in the Mediterranean basin. Severity of aphid infestations is determined by environmental variables, host plant phenology patterns, and the biological control exerted by their associated natural enemies. However, there is no information about the role these limiting and regulating factors play. Aphid densities, citrus phenology, and associated predators that overwinter in the crop were monitored weekly throughout two flush growth periods (February to July) in four clementine mandarin groves; relationships between these parameters and environmental variables (temperature and precipitation) were studied. Our results show exponential increase in aphid infestation levels to coincide with citrus phenological stages B3 and B4; shoots offer more space and nutritional resources for colony growth at these stages. Duration of these phenological stages, which was mediated by mean temperature, seems to importantly determine the severity of aphid infestations in the groves. Among those studied, the micro-coccinellids, mostly Scymnus species, were the only group of predators with the ability to efficiently regulate aphid populations. These natural enemies had the highest temporal and spatial demographic stability. Aphid regulation success was only achieved through early presence of natural enemies in the grove, at the aphid colonization phase. Our results suggest that conservation strategies aimed at preserving and enhancing Scymnus sp. populations may make an important contribution to the future success of the biological control of these key citrus pests.


2013 ◽  
Vol 61 (5) ◽  
pp. 394 ◽  
Author(s):  
Scott H. Altmann

An understanding of the impact that climate change will have on dominant plant species is important given the central role of these species in ecosystem functioning. Southern beech (Nothofagus Blume) is a central genus in the forests of the southern cone of South America, with Nothofagus glauca (Phil.) Krasser a dominant, at-risk tree inhabiting the drought-prone region of central Chile. The present study explored the relationships among several environmental variables that may be critical to understanding the impact of climate change on N. glauca, most importantly crown condition, plant water availability, insect leaf damage and landscape features. Furthermore, the study examined whether these variables differed between individuals from drier or wetter stands distributed within a north–south geographic area. Multiple regression modelling detected important relationships for the dependent variable crown condition with branch midday water potential, N. glauca diameter at breast height and vegetative cover, as well as with landscape variables in interaction with different plant vigour and water availability measures. Negative correlations between insect damage and plant water availability measures were observed at two field sites. Overall, crown condition and water availability were higher, and insect damage was lower, in wetter stands. The results of the present study have important negative implications for the species in terms of climate change and can be applied to future investigations.


Evolution ◽  
1990 ◽  
Vol 44 (3) ◽  
pp. 629-636 ◽  
Author(s):  
T. K. Wood ◽  
K. L. Olmstead ◽  
S. I. Guttman

2021 ◽  
Author(s):  
Aapo Kahilainen ◽  
Vicencio Oostra ◽  
Panu Somervuo ◽  
Guillaume Minard ◽  
Marjo Saastamoinen

Author(s):  
J. H. Lawton ◽  
M. MacGarvin

SynopsisBracken in Britain is a host for 27 species of insect herbivores, with a further 11 species that either feed below ground (and are poorly studied), or appear to be only rarely associated with the plant. A typical site in northern England has an average of 15–16 of these species in any one year. Compared with perennial herbaceous angiosperms with similar wide distributions, bracken is not noticeably depauperate in the number of insect species that feed upon it. Bracken in others parts of the world is attacked by a wide variety of insects, with more species present in the geographical areas where bracken is most common.The ‘feeding niches’ of some of these insects are reviewed. Most are very rare relative to the biomass of their host plants, probably because of the impact of natural enemies; the effect of most of the insects upon their host-plant is consequently negligible.Reverse effects, of host-plant upon the insects, are subtle but poorly understood. Experiments to elucidate these effects are briefly outlined.


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