CDM Diagnostic Key - Question 2 - Cucurbit Downy Mildew ipmPIPE

Question 2: Is there dark gray-brown to purplish sporulation on the lower leaf surface?

Fig 7. Very light purple-gray sporulation on the underside of a cucumber leaf (Beth K. Gugino, Penn State)

Fig 8. Moderate sporulation on the lower leaf surface of pumpkin (Beth K. Gugino, Penn State)

Fig 9. Advanced sporulation on the lower leaf surface of cucumber (Beth K. Gugino, Penn State)

Yes

Sporulation under magnification

fig4 — Fig 10. CDM hand-lens drawing and description from hand-lens key

Fig 12. Microscopic view of spores reveals acutely and dischotomously branched sproangiophores bearing lemon-shaped sporangia (Gerald Holmes, Strawberry Center, Cal Poly San Luis Obispo, Bugwood.org)

The forecast(s) presented in this report only represent estimates of pathways spores are likely to travel from confirmed sources. The forecasts were prepared for purposes of supporting the research and extension functions of North Carolina State University. The forecasts contained herein were not prepared or issued in support of business, industrial, or investment decisions whether they are profit-making or otherwise. The authors; the Department of Plant Pathology; Department of Marine, Earth, and Atmospheric Sciences; North Carolina State University; The University of North Carolina, their Governors, Trustees, officers, administrators, employees, and agents do not assume any responsibility for any interpretations of the data, nor do they warrant the fitness of the forecasts for any use.

NOTE: These forecasts/outlooks apply ONLY to disease development from AIRBORNE TRANSPORT of spores. We do not have the capability to track cucurbit downy mildew development by other means, such as transporting infected materials, nor will we attempt to do so. Please consult the County Extension Service personnel in your area if you have questions about these matters. ***

CDM Diagnostic Key – Question 2