Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu
Disease Severity Value (DSV) Accumulation as of July 22, 2009 is as follows:
Location: Shadybrook Farms, Little Creek, DE in Kent County.
Greenrow: May 1
| LATE BLIGHT | EARLY BLIGHT | |||
| Date | Daily DSV | Total DSV | Spray Recs | Accumulated P-days* |
| 7/1 | 2 | 114 | 10-day interval | 519 |
| 7/2 | 1 | 115 | 10-day interval | 528 |
| 7/3-7/5 | 0 | 115 | 10-day interval | 555 |
| 7/6-7/8 | 0 | 115 | 10-day interval | 581 |
| 7/9-7/12 | 0 | 115 | 10-day interval | 616 |
| 7/13-7/15 | 0 | 115 | 10-day interval | 641 |
| 7/16 | 0 | 115 | 10-day interval | 647 |
| 7/17-7/18 | 2 | 117 | 10-day interval | 662 |
| 7/19-7/20 | 1 | 118 | 10-day interval | 680 |
| 7/21 | 2 | 120 | 7-day interval | 690 |
| 7/22 | 0 | 120 | 7-day interval | 698 |
There have been no new late blight reports on potato in the region. A backyard tomato sample from the Ellendale vicinity was diagnosed on Wed. July 22 with late blight. This is the first report of late blight on tomato in DE.
Current conditions here are favorable again for late blight on tomato. The favorable weather of the last few days will continue to provide favorable weather for late blight especially if thundershowers materialize. Most potatoes will be, or are, close to maturity so they are not particularly at risk at the present time.