scholarly journals Factors affecting the amount of infection obtained by aphis transmission of the virus Hy. III

1936 ◽  
Vol 226 (540) ◽  
pp. 457-489 ◽  
Keyword(s):  
Plant Virus ◽  
Host Plants ◽  
Suitable Host ◽  
Factors Affecting

Much of the information which can be obtained about a plant virus agent is ultimately derived from the quantity as well as the type of the infections resulting from inoculations to suitable host plants. The number ofinfections obtained does not depend solely on the nature of the particular virus concerned. It is dependent on other variable factors, such as the efficiency of the means of infection introducing the virus, the susceptibility of the plants receiving it, and the concentration of the virus in the source from which it was obtained. In this paper a'n attempt has been made to estimate the effect of some of these variables on infection by insects.

Factors affecting the response ofLongitarsus jacobaeae(Coleoptera: Chrysomelidae) to upwind plant odours

1996 ◽  
Vol 86 (3) ◽  
pp. 307-313
Author(s):  
Zhi-Qiang Zhang ◽  
Peter B. McEvoy
Keyword(s):  
Wind Tunnel ◽  
Host Plants ◽  
Local Density ◽  
Flea Beetle ◽  
Late Summer ◽  
Developmental State ◽  
Early Summer ◽  
Directed Movement ◽  
Factors Affecting ◽  
Plant Odours

AbstractFactors (developmental state, starvation time, host local density and host distance from insects) affecting the response of the ragwort flea beetle,Longitarsus jacobaeae(Waterhouse), to upwind plants of tansy ragwort,Senecio jacobaeae(Compositae), were examined in a wind tunnel. There was seasonal variation in beetle response to host odours. Individuals collected during spring and early summer (6 May to 14 July 1993) showed directed movement toward the upwind plants. However, individuals collected in mid-summer (23 July 1993) showed no significant response to upwind host plants and walked randomly in the wind tunnel. Individuals collected during late summer to autumn (4 August to 23 October 1994) once again showed response to upwind plants, whereas those collected in winter (January 1994) walked randomly in the wind tunnel. The absence of beetle response to plant odours coincided with potential summer aestivation and winter ‘hibernation’. For spring and early summer beetles that responded to plant odours, the strength of the response did not change significantly with the number of plants (1, 2, 4 or 6) presented upwind in the tunnel nor with the starvation time (2, 6, 10, 12, 24 or 36 h) of the tested beetles, and these patterns were consistent for male and female beetles. Individuals responded to plants from a distance of 60 and 300 cm. The speed of movement, similar for males and females, increased slightly asL. jacobaeaeoriented more directly toward host plants.

The Role of Host Selection in the Ecology of Phytophagous Insects

1953 ◽  
Vol 85 (8) ◽  
pp. 276-282 ◽  
Author(s):  
A. J. Thorsteinson
Keyword(s):  
Host Plant ◽  
Host Selection ◽  
Host Plants ◽  
Host Plant Selection ◽  
Phytophagous Insects ◽  
Phytophagous Insect ◽  
Ecological Significance ◽  
Plant Selection ◽  
Suitable Host

It is a commonplace entomological observation that each phytophagous insect is restricted in its feeding to a small fraction only of the plant species that grow in any area. This phenomenon is generally referred to as “host selection”. The ecological significance of host plant selection among insects is manifest principally in an effect on the geographical distribution of insect species since phytophagous insects can occur only where suitable host plants are available.

Tea green leafhopper, Empoasca vitis, chooses suitable host plants by detecting the emission level of (3Z)-hexenyl acetate

2016 ◽  
Vol 107 (1) ◽  
pp. 77-84 ◽  
Author(s):  
Z.-J. Xin ◽  
X.-W. Li ◽  
L. Bian ◽  
X.-L. Sun
Keyword(s):  
Host Plants ◽  
Oviposition Preference ◽  
Green Leaf Volatiles ◽  
Hydroperoxide Lyase ◽  
Future Research ◽  
Suitable Host ◽  
Leaf Volatiles ◽  
Green Leafhopper ◽  
Hexenyl Acetate ◽  
Empoasca Vitis

AbstractGreen leaf volatiles (GLVs) have been reported to play an important role in the host-locating behavior of several folivores that feed on angiosperms. However, next to nothing is known about how the green leafhopper, Empoasca vitis, chooses suitable host plants and whether it detects differing emission levels of GLV components among genetically different tea varieties. Here we found that the constitutive transcript level of the tea hydroperoxide lyase (HPL) gene CsiHPL1, and the amounts of (Z)-3-hexenyl acetate and of total GLV components are significantly higher in tea varieties that are susceptible to E. vitis (Enbiao (EB) and Banzhuyuan (BZY)) than in varieties that are resistant to E. vitis (Changxingzisun (CX) and Juyan (JY)). Moreover, the results of a Y-tube olfactometer bioassay and an oviposition preference assay suggest that (Z)-3-hexenyl acetate and (Z)-3-hexenol offer host and oviposition cues for E. vitis female adults. Taken together, the two GLV components, (Z)-3-hexenol and especially (Z)-3-hexenyl acetate, provide a plausible mechanism by which tea green leafhoppers distinguish among resistant and susceptible varieties. Future research should be carried out to obtain the threshold of the above indices and then assess their reasonableness. The development of practical detection indices would greatly improve our ability to screen and develop tea varieties that are resistant to E. vitis.

Viability and Fecundity of Alate Alienicolae of Aphis Fabae Scop. After Flights to Exhaustion

1961 ◽  
Vol 38 (1) ◽  
pp. 181-187
Author(s):  
A. J. COCKBAIN
Keyword(s):  
Host Plants ◽  
Reproductive Potential ◽  
Adult Life ◽  
Reproductive Rate ◽  
Aphis Fabae ◽  
Adult Longevity ◽  
Survival Times ◽  
Suitable Host ◽  
Broad Beans ◽  
And Control

1. Laboratory-reared 24 hr.-old alate alienicolae of A. fabae were flown for variable periods, but all to apparent exhaustion; their subsequent longevity and fecundity on broad beans, or their survival times during starvation, were compared with controls. 2. Adult longevity, reproductive rate and capacity, and nymph viability were similar in exhausted and control aphids that settled on host plants after flight. Mean adult life was 31 days in exhausted aphids and 32 days in the controls. Both exhausted and control aphids produced an average of 84 larvae per adult. 3. The only major difference noted between exhausted and control aphids that fed after flight was a reluctance, or inability, of exhausted aphids to fly on the following day. 4. Exhausted aphids starved after flight lived for a significantly shorter time (mean of 30 hr.) than control aphids starved without flight (55 hr.). 28% of the exhausted and 88% of the control aphids could take-off on the next day. 5. The results indicate that long migratory flights are unlikely to affect the reproductive potential of aphids, and that alate alienicolae of A. fabae, having settled on a suitable host after an exhaustive flight, are unlikely to fly again.

Planococcus citri (citrus mealybug).

2021 ◽  
Author(s):  
Gillian Watson
Keyword(s):  
Plant Material ◽  
Plant Virus ◽  
Host Plants ◽  
Planococcus Citri ◽  
Virus Diseases ◽  
Citrus Mealybug ◽  
Fresh Plant Material ◽  
The World ◽  
Cacao Swollen Shoot Virus ◽  
Human Transport

Abstract Planococcus citri is a highly polyphagous, adaptable mealybug that can feed on many host plants in a variety of conditions, and can reproduce rapidly. It has been reported on over 200 host-plant species belonging to 191 genera and 82 families, and can seriously damage many crops, particularly citrus and glasshouse tomatoes. It is known to transmit some plant virus diseases like Cacao swollen shoot virus. The mealybug is of Old World origin, but its polyphagy has facilitated its spread about the world by human transport of infested plants over many years, and it is now established in in all the temperate and tropical zoogeographic regions, and lives under glass in higher latitudes. Its small size and cryptic habits makes it difficult to detect and identify at plant quarantine inspection. The increase in international trade in fresh plant material in recent years is facilitating its continued spread.

Lymantria dispar (gypsy moth).

2021 ◽  
Author(s):  
Patrick Tobin
Keyword(s):  
Gypsy Moth ◽  
Lymantria Dispar ◽  
Range Expansion ◽  
Host Plants ◽  
Reproductive Rate ◽  
Urban Landscapes ◽  
Suitable Host ◽  
Tropical Regions ◽  
Asian Strain ◽  
Successful Invader

Abstract The gypsy moth is likely to ultimately occupy virtually all portions of the temperate world where oaks and other suitable host plants occur. Consequently, the northern hemisphere is more at risk for establishment than the southern hemisphere though some suitable hosts do occur in these areas. The gypsy moth is apparently not able to persist in very cold (e.g. Finland) or warm (subtropical to tropical) regions. The gypsy moth is a 'proven' invader. The broad range of host plants that it utilizes (Liebhold et al. 1995), along with its high reproductive rate combine to make this insect a very successful invader of many types of forest and urban landscapes. Another characteristic that contributes to the gypsy moth's invasiveness is its propensity to be transported on human-made objects (e.g., egg masses can be laid on vehicles, logs, etc.). Perhaps the greatest limitation this species has as an invader is that females (of the European strain) are incapable of flight and this limits its rate of unassisted range expansion. However, as females of the Asian strain are capable of flight and all strains can lay their eggs on human-made objects, established populations are nevertheless able to spread.

scholarly journals Effect of Different Plants on the Growth and Reproduction of Thrips flavus (Thysanoptera: Thripidae)

Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 502
Author(s):  
Yu Gao ◽  
Yijin Zhao ◽  
Di Wang ◽  
Jing Yang ◽  
Ning Ding ◽  
...  
Keyword(s):  
Host Plant ◽  
Host Plants ◽  
Solanum Melongena ◽  
Insect Development ◽  
Life Table Analysis ◽  
Suitable Host ◽  
Table Analysis ◽  
Development Duration ◽  
Growth And Reproduction ◽  
Duration Of Development

Host plants play an important role in affecting insect development and reproduction. Understanding the host plant preferences is important for pest control. Thrips flavus Schrank (Thysanoptera: Thripidae) is a worldwide phytophagous pest in Palearctic Asian and European countries. We used a life table analysis to study the development duration, population parameters, and population growth of T. flavus on five plant species, including Solanum melongena (Solanaceae), Capsicum annuum (Solanaceae), Glycine max (Leguminosae), Brassica rapa var. glabra (Cruciferae), and Cucumis sativus (Cucurbitaceae). The results showed that T. flavus can survive and reproduce on Cu. sativus and G. max, which were two potentially suitable host plants. T. flavus preferred to oviposit on Cu. sativus with a shorter duration of development (17.8 days) at 25 °C. Therefore, the host plant was an important factor influencing the development and fecundity of T. flavus populations. These results will improve our understanding of the population dynamics of T. flavus and facilitate the development of more scientific and efficient measures to control thrips.

scholarly journals Distinct Transcriptional Programs Underlie Differences in Virulence of Isolates on Host Plants in a Fungal Pathogen, Colletotrichum gloeosporioides

2021 ◽  
Vol 12 ◽  
Author(s):  
Wonsu Cheon ◽  
Young Soo Kim ◽  
Kotnala Balaraju ◽  
Younmi Lee ◽  
Hyeok Tae Kwon ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Host Plants ◽  
Colletotrichum Gloeosporioides ◽  
Isocitrate Lyase ◽  
Glyoxylate Cycle ◽  
Virulence Gene ◽  
Rna Seq ◽  
Susceptible Host ◽  
Factors Affecting ◽  
Different Types

Susceptible host plants challenged by fungal pathogens can display different types of lesions, which can be attributed to environmental factors affecting the nature of interactions between the host and pathogen. During our survey of apple anthracnose in Korea, two distinct types of disease symptoms, designated as progressive (PS) and static symptoms (SS), were recognized. PS is a typical, rapidly enlarging symptom of apple anthracnose, while SS is a small, dark speck that does not expand further until the harvesting season. Isolation and genotyping of pathogens from disease lesions suggested that all of them belong to Colletotrichum gloeosporioides, a well-known causal agent of apple anthracnose. Two types of isolates were comparable in growth on media, spore germination and appressorium formation, virulence test on fruits at various temperature conditions. Furthermore, they were analyzed at the molecular level by a phylogenetic tree, RNA-seq, and expression of virulence gene. However, the SS isolates were defective in appressorium-mediated penetration into the underlying substratum. RNA-seq analysis of PS and SS isolates showed that distinct transcriptional programs underlie the development of different types of anthracnose symptoms in host plants. One downregulated gene in SS encoded isocitrate lyase is essential for disease development via its involvement in the glyoxylate cycle. It partly explains why SS is less virulent than PS on host plants. Overall, our work challenges the traditional view on the development of different lesion types and provides valuable insights into variations that exist in the pathogen population.

Factors Affecting the Metabolite Productions in Endophytes: Biotechnological Approaches for Production of Metabolites

2020 ◽  
Vol 27 (11) ◽  
pp. 1855-1873 ◽  
Author(s):  
Viridiana Morales-Sánchez ◽  
Maria Fe Andrés ◽  
Carmen Elisa Díaz ◽  
Azucena González-Coloma
Keyword(s):  
Host Plants ◽  
Large Scale ◽  
Fungal Endophytes ◽  
Optimization Process ◽  
Factors Affecting ◽  
Medicinal Compounds ◽  
Different Strains

:Since 1980, many species and different strains from endophytic genera of Phomopsis, Fusarium, Pestaliopsis and Aspergillus have been studied because of their ability to produce medicinal compounds found in their host plants. Some of these medicinal agents such as Taxol, Brefeldine A, Camptothecin and Podophyllotoxin are being produced in large-scale after an optimization process. However, the potential of fungal endophytes to produce host-like medicinal compounds remains largely unexplored.

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