1. Fighting bacterial wilt with row covers Erika Saalau and Mark L. Gleason Plant Pathology Department Iowa State University

2.  Transplanted in May-June  First harvest by August  Early muskmelons = premium prices

3.  Adult beetles overwinter near fields  Become active in May  Look for young cucurbits  Feed, reproduce, lay eggs  Next generation emerges in fields

4.  Caused by Erwinia tracheiphila  Transmitted by cucumber beetles  Plants wilt and die

5. Overwintering adults Cucurbit seedlings Transmission Symptoms Beetles reproduce Acquire bacteria

6. How do plants become infected with the disease? ??

7.  Early!!!  Highest risk period= early beetles

8.  Managing beetles!!!  Insecticides  Trap crops  Baited traps  Row covers Management

9. Why row covers?  Protect from frost and extreme weather conditions  Increase earliness and yield  Prevent insect damage  Protect from bacterial wilt!!!

10. How do they work?

11. What about pollination?  Timing of removal  Conventional removal= flowering  Could row covers stay on a bit longer?

12.  Open row cover ends for pollinators  Add bumblebees  Remove row covers 10 days after flowering

13.  Plants were covered from transplant  No insecticides were applied!

14. No Row Cover Remove covers at flowering No Row Cover At flowering: Open ends Add bumblebees

15. No row covers Row covers removed @ anthesis Delayed-removal row covers

16.  Delaying removal by 10 days can provide season-long protection against bacterial wilt.  This strategy can reduce the need for insecticides.

17. No row covers Row covers

18.  All row cover treatments suppressed bacterial wilt

19.  No beetles! =  No disease

21. Delayed RC None RC removed at bloom None RC removed at bloom

22.  Sporadic disease in the Midwest  Delayed-removal strategy may provide consistent returns.

23. Do you feel lucky?

24.  Cost effectiveness is affected by how often bacterial wilt outbreaks occur.  Delayed-removal strategy was advantageous when wilt occurred ≥ 50% of the growing seasons.

25.  USDA's Organic Research and Extension  Pennsylvania, Kentucky, and Iowa http://organiccucurbit.org/