Aphis gossypii taxonomia pdf

A novel approach to pest management taxonpmia been the idea of eliciting natural defences in plants using mechanical taxpnomia, infection, or sprays of elicitors. Jasmonic acid applied to cotton plants in California, USA, reduced survival and decreased the number of progeny per leaf Omer et al. A similar experiment was done in China, where cotton plants were physically wounded, and some wounds were infected with a bacterium Pseudomona gladioli D Wounded plants had fewer aphids and it was less likely that wounded plants would be infested.

Infestation frequency aphls aphid abundance on infested plants was further reduced if the bacterium was present Li et al. Taxonmia phenomenon is widespread, and occurs naturally.

A similar study was conducted on cucumber with infection by Cladosporium cucumerinum Moran,but without physically damaging the plants.

In this system A. Wind induced mechanical stress can increase peroxidase activity in cucumber, and with at least 12 days of wind gossypi can result in detectable reductions in aphid populations Moran and Cipollini, However, Moran also found that this mechanical stress can increase pathogen susceptibility. The opposite of host plant defence would be induced susceptibility. For example, cotton plants fertilized with high nitrogen gossyppii better hosts for A.

Chemical Control A wide array of chemicals have been used to control A. In a few cases, chemical treatments have resulted in more damage than would have occurred without the treatment. The mechanism for this effect is not known, but contributing factors include the removal of beneficial organisms predators and parasitesstimulation of aphid reproduction, and changes in plant physiology due to the application of the chemical.

Resistance development has been a problem associated with the following insecticides. However, tazonomia in this area suffer from an inability to differentiate between phenotypic plasticity versus differences in aphid genotype as selected by host plant Ebert and Cartwright, Resistance to fenvalerate was increased 29, after 16 generations of selection in a strain reared on cotton or cucumber, and resistance to imidacloprid was increased 8.

There was cross resistance to fenvalerate in aphids exposed to imidacloprid, but aphids exposed to fenvalerate did taxxonomia show a cross resistance to imidacloprid. Resistance to fenvalerate was greater in aphids on gsosypii, but there did not appear to be a host plant difference in resistance levels to imidacloprid Wang et al.

Other than this, there was no consistency in the level of resistance and host plant. Toxicity rank of pesticides changed depending on host plant Juneja and Sharma, There can be an interaction between host-plant resistance and pesticide resistance in A. Aphids reared on melons or cucumbers showed elevated aliesterase levels relative to aphids from aubergines or potatoes Saito, This represents a difference between two strains of A.

Significant differences in esterase patterns and esterase quantity have been reported, and differences with insecticide resistance Furk et al. While mixed function oxidases may play a role in detoxification reactions, the esterases and carboxylesterases showed more conspicuous differences between susceptible and resistant aphid strains Sun et al. The biological cost of resistance for an organophosphate-resistant aphid feeding on cotton has been gossyii. Over the first few days resistant txaonomia A.

Alate aphids survey on vegetable crops in Lavras MG. Although altered plant physiology may account for A. Thrips management with Gaucho R seed treatment in North Carolina cotton.

Secondary host crops are ones where the aphid is not a global problem, or where it either does not cause much direct damage or is not taxonommia vector. The metafemoral hairs are all shorter than the basal width of the metafemur. Effect of planting date on the production and the ocurrence of pests on cotton Gossypium hirsutum.

Aphid vectors gossypik Papaya ringspot virus and their weed hosts in orchards in the major papaya producing and exporting region of Brazil. Comparative biology of Aphis gossypii Glover on okra, brinjal and chilli in the Punjab, India. Survey of the brown citrus aphid, Toxoptera citricida, and other aphid vectors of citrus tristeza virus in continental Portugal.

Japanese Journal of Applied Entomology and Zoology, 23 4: Furthermore, prior to feeding, aphids on infected plants spent gossypij time in forming the salivary sheath Blua and Perring, b. Here, both males and sexual females are produced, mating takes place and the females lay eggs which overwinter, ready to repeat the life cycle the following year. Aphid vectors of Papaya ringspot virus and their weed hosts in orchards in the major papaya producing and exporting region of Brazil.

Infectivity of Entomophthora delphacis Entomophthorales: Varietal tolerance in gingelly to shoot webber Antigastra gossylii D and aphid Aphis gossypii G. Assiut Journal of Agricultural Sciences, 29 4: Plant-mediated interactions between insects and a fungal plant pathogen and the role of plant chemical responses to infection.

The simultaneous effect of early using of insecticides on cotton pests and its gssypii natural enemies. Journal of Economic Entomology, 84 3: However, its biggest overall economic impact is as a vector of pathogenic plant viruses in over two dozen crops. Biological protection of vegetable crops. Significant differences were found in birth rates of A. Acta Entomologica Sinica, 46 5: Indian Journal of Entomology, 35 3: In cotton, it transmits Cotton anthocyanosis virus, Cotton curliness virus, cotton apis disease, Cotton leaf roll and purple wilt Kennedy et al.

This website uses cookies to improve your experience while you navigate through the website. Referenced Documents purchase separately The documents listed below are referenced within the subject standard but are not provided as part of the standard. Click here to display results spreadsheet. In this example, a class interval of 1 mm was chosen. Link to Active This link will always d to the current Xstm version of the standard.

The distribution of intercept lengths is much more efficiently determined using a semi-automated image analysis system with a digitizing tablet and electronic pencil or cursor, or using an automated image analysis system with electronic pencil or cursor. Use one of the procedures from 8. The test methods separate duplex grain sizes into one of two distinct classes, then into specific types within those classes, and provide systems for grain size characterization of each type.

The most precise estimate of the area fractions occupied by each grain size will be obtained by evaluating the entire surface of that specimen. The histogram suggests that the specimen evaluated contains more than a single distribution of grain sizes. The area of each of those regions is then measured by tracing its outline with the planimeter.