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By Ismael Escobar and Dr. Rebecca Creamer ASSURED Program 2007

By Ismael Escobar and Dr. Rebecca Creamer ASSURED Program 2007. Non-Preference Feeding Of Beet Leafhopper on Tabasco Pepper as A Resistance Mechanism to Beet Curly Top Virus. Introduction. A problem in the USA since 1899 Infects crops and weeds

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By Ismael Escobar and Dr. Rebecca Creamer ASSURED Program 2007

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  1. By Ismael Escobar and Dr. Rebecca Creamer ASSURED Program 2007 Non-Preference Feeding Of Beet Leafhopper on Tabasco Pepper as A Resistance Mechanism to Beet Curly Top Virus

  2. Introduction • A problem in the USA since 1899 • Infects crops and weeds • The crops are peppers, tomatoes, sugarbeets, spinach, melons and beans • Youngest plants most susceptible to infection • Transmitted by the leafhopper

  3. Symptoms of Curly Top in Chile • Disease reported in peppers in NM in 1927 • Severely stunted plants • Some plants have chlorotic rolled leaves • Small rounded fruit • Stiff plants with brittle leaves • Symptoms appear 1-2 weeks after infection • Plants infected when young may die

  4. The Beet Leafhopper • Feeds on a wide host range of plants • Prefers semi-arid and arid areas • Can transmit viruses to plants on which it can’t complete its life cycle

  5. Vector Identification • 3-3.5 mm length • Robust with lots of spines • Light tan to yellowish to gray • Color and size vary slightly with season • Found throughout western USA • 3 morphs - summer, winter, and migratory

  6. Curly Top Transmission • Transmits virus in a circulative manner • Can acquire virus after feeding for 15 min, but with longer feeding (48 hr) acquires more virus • Can transfer virus to healthy plant with few minutes of feeding, but transmit better if longer • Can continue to transmit the virus for days • Requires 4 hr latent period in insect before transmitting

  7. Management Options • Heavy seeding • Weed removal • Plant resistance in bean, sugarbeet, tomatoes, none in chile • Kaolin sprays • Insecticides - to decrease leafhopper numbers • Predictive model

  8. Objective • To determine the preference of the Beet leafhopper between Tabasco and NM64.

  9. Hypothesis • The NM64 is going to be the more susceptible to be affected by the virus.

  10. Plant Resistance • Commercial varieties susceptible to, other Capsicum species appear to have some level of resistance. • Tabasco vs. NM64

  11. Methods and Materials • Plants were grown in greenhouse • Cotyledons were caged in sets of 4 with 5 leafhoppers for 19 hours. • After 2 weeks plants were set for staining, DNA extraction and PCR.

  12. Methods and Materials • Leaf Staining (Acid Fuschin) • Confirmation by microscope by staining stylet tracks and punctures • Examined 1 leave/plant • Extraction/PCR • PCR using CP4r & CP6f

  13. Punctures and Stylet Tracks

  14. Staining and PCR Results • Tabasco plants with leafhoppers had an average of 6.3 punctures per leaf and the range was from 0 to 28. Stylet tracks had an average of .14 • NM64 with leafhoppers had an average of 15.6 punctures per leaf and the range was from 6 to 33. Stylet tracks had an average of .2 • None of the plants with leafhoppers tested positive to Curly Top Virus.

  15. Staining and PCR Results • Tabasco plants without leafhoppers had an average of 0.4 punctures per leaf and no stylet tracks. • NM64 plants without leafhoppers had an average of 2.8 punctures per leaf and no stylet tracks. • None of the plants without leafhoppers tested positive to Curly Top Virus.

  16. Conclusion • NM64 had a higher number of punctures than Tabasco due to preference of the leafhopper. • Plants without leafhoppers had punctures due to white flies in the greenhouse.

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