Lecture 23: Trade and pests

1. Lecture 23: Trade and pests

2. Key Points:Trade and pests • ID the below three species • CPB • SWD • BMSB • What is the underlying reason why problems like CPB develops • Which of these three abovementioned species switched hosts • Which species affects small fruit • Which species affects fruit, veg and nurseries

3. CPB: A serious pest of potatoes • now cosmopolitan • with a fascinating history Handsome devil, ‘eh?

4. Voyage of the Beetle • 17th century & the Spanish Conquista • Living in central Mexico was a beetle which fed on burweeds (Solanumrostratum) It’s name was Leptinotarsa decemlineata

5. Burweed • also known as Buffalo Bur &/or Kansas Thistle • Native of Meso-America (NOT North America) • Primary host plant for L. decemlineata

6. L. decemlineata • Life History • wet season & female cements her eggs to bur weed leaves - batches of ca. 20 eggs

7. L. decemlineata • Adults are brightly colored • warning coloration • “mess with me & I’ll toss my cookies” • Larval beetle is brightly colored

8. L. decemlineata • Both adult and larval beetles are defoliators

9. L. decemlineata Step Number One Necessary to get this

10. L. decemlineata • Note: • In the 17th century the potato was NOT found in North America or Mexico. • In the 17th century L. decemlineata was NOT a pest insect for the indigenous peoples of Meso America.

11. Voyage of the Beetle • Spanish introduced cattle to the “New” world • “Vaca” driven to northern markets in Texas in late 17th & early 18th centuries. • The cows carried the spiny seeds of the burweed, and the plant began a northward migration. • Bison also picked up the burweed seeds and carried them even further north.

12. Voyage of the Beetle • As the host burweed plant moved north, so followed thebeetle. • The beetles followed the northward trail of their host plant and by 1820 had reached the Great Plains of America. • It was here that the beetle was discovered by the entomologist Thomas Say and named.

13. The potato • Native to the western highlands of South America • Solanumtuberosum • a.k.a. the IRISH potato “Discovered” by Franciso Pizarro in 1531 during his “rape” of the Inca empire.

14. The potato Popular Elizabethan English legend has it that the potato was brought to England about 1580 by either • Sir Francis Drake, or Sir Walter Raleigh, or Both!!

15. The potato • 1719 • potato seed stock sent from Ireland back to the “New” World (New Hampshire, actually). • Potato culture (growing) spread quickly throughout America • Hypothesized that L. decemlineatafirst encountered potatoes ca. 1820

16. The potato & the beetle • 1859 • CPB made the transition from burweed to potato in central plains of U.S. • CPB population EXPLODED • Described in terms of biblical plagues, especially along the northeastern U.S. seaboard potato growing regions.

17. The potato & the beetle 1875 • CPB crosses the Atlantic to England {a small gift to our cousins} • during the next 100 years they spread throughout Europe.

18. The potato & the beetle • 1900 • W.L. Tower shows that CPB originated in Mexico, NOT Colorado or Iowa as many believed. • Mexican CPB populations have yellow larvae that do not eat potatoes • American CPB populations have red larvae that love to eat potatoes • Tower believed the CPB of the U.S. was a new “variety”/subspecies.

19. The potato & the beetle • 1982 • T.H. Hsiao (geneticist at Utah State Univ.) • Found a chromosomal inversion in the potato eating variety of the CPB • Potato eating gene (allele) found to be dominant & explained the feed switch which elevated the beetle into major pest status.

20. Final Thoughts Very minor genetic differences have enabled the beetle to switch plant hosts. {And} the beetle populations that have followed have had a major impact on our agriculture and history. Lu & Lazell - 1996

21. CPB Control • Huge list of chemical materials. • Some novelties: • Transgenic potatoes that have had B.t. genes incorporated so that the plant produces B.t. toxins. • Sounds good!! But what are some problems?? • Resistance • use as human food

23. Spotted Wing Vinegar Fly a.k.a Cherry Vinegar Fly Drosophilasuzukii The “Newest” Plague to the PNW

24. Drosophila diversity

25. D. suzukii Female flies about to oviposite on a rasp- berry fruit.

26. Hosts

27. Infested blueberry {with oviposition holes} Fly larvae exiting blueberry

28. Spotted Wing Drosophila D. Dalton

29. D. suzukii biography • First “discovered” in Japan {1916} • Pest throughout Asia • First seen in U.S. in the autumn of 2008 {California} • First seen in PNW in 2009 • Blueberries & Raspberries = 20% loss • California cherry industry = 30% loss

30. SWD U.S. Distribution 2010

31. D. suzukii biology • Thrives in cooler climates {read that as the Willamette Valley} • Up to ten generations per year • Short life cycle (egg to adult) = as little as ten days • Multiple fruit hosts available in western fruit growing regions of the PNW.

32. The future: Brown Marmorated Stink Bug This bug has a wide host range, potentially causing even more economic damage than SWD

33. Key Points:Trade and pests • ID the below three species • CPB • SWD • BMSB • What is the underlying reason why problems like CPB develops • Which of these three abovementioned species switched hosts • Which species affects small fruit • Which species affects fruit, veg and nurseries