Vector-Borne Pathogens: Influence on Disease Development

Vector-borne diseases are generally monocyclic with only one transmission cycle within one season.

Aphids have two forms of adults: apterae (without wings local movement resulting in aggregation) and alatae (winged forms that can disperse over short and long distances).

The effect of wind on the spatial spread of black currant reversion virus transmitted by aphids can be estimated using the 'multiple infection transformation' ln[1/(1-x)], where x is the proportion of diseased plants or diseased area.

Prevention of landing of the vector on the crop may work better, for example by reflective mulches or a barrier with insecticide strip.

Host plant resistance to the vector and pathogen is not an effective control method for vector-borne diseases.

Roguing of post-infectious plants has no effect on disease development.

Roguing of infectious symptomatic and asymptomatic plants can be effective in controlling the spread of vector-borne diseases.

Generally, a combination of different control tactics is not needed to reduce epidemic development of vector-borne diseases.

The distribution of wheat streak mosaic virus transmitted by the wheat curl mite, as measured by a spectral reflectance meter at different distances from the edge of a field, is shown by the dotted line in the graph.

The incidence of tomato yellow leaf curl, transmitted by Bemisia tabaci whiteflies, is not affected by the use of a barrier with insecticide.

Yellow sticky traps are less effective for Homoptera than water pans.

Trap design does not affect catch.

Real-time quantitative PCR methods can be used for identifying and quantifying viruses in plants or vectors.

Amplicon sequence non-specific methods, such as SYBR Green I, show fluorescence proportional to total dsDNA.

Amplicon sequence specific methods include TaqMan, Molecular beacons, Scorpion PCR, and probes labeled with a donor fluorophore and acceptor dye.

Vector relationships include specificity and persistence, which can affect epidemic development.

There are four steps in vector transmission: acquisition, movement inside the vector, multiplication, and inoculation.

Factors affecting transmission and epidemic development include the proportion of infected source plants, pathogen content, vector density, vector aggregation, vector movement, and presence of alternate hosts.

Modeled virus transmission includes acquisition and inoculation over time, as well as disease incidence over time for various types of viruses.

Vectors are not more attracted to diseased plants, indicating co-evolution.

Vector-borne pathogens can include viruses, bacteria, and some fungi.

The main insect vectors that transmit viruses, bacteria, and mollicutes belong to the order Lepidoptera.

Some viruses can be transmitted by thrips, mites, fungal-like organisms, or nematodes.

Spores of plant pathogenic fungi can be transmitted by bees and butterflies.

Pathogen population size does not influence disease development.

For many plant virus diseases, the epidemiologically important propagule is often the vector.

The text mentions that the same is true for phloem-limited bacteria or mollicutes.

Quantifying viruses and other pathogens in vectors is not important for plant virus diseases.

The text mentions that the same is true for phloem-limited bacteria or mollicutes.

Pathogen ecology, such as being soilborne or foliar, does not influence disease development.