These shots of Sudden Death Syndrome ( SDS ) were taken near Florence, Ontario.Double click on the above and below photos and you'll get a more clear impression of just how much infection has occurred in this particular field.Notice how the leaves on infected plants are wilting and curling.
SDS is more pronounced this year because of the prolonged cool wet spring we experienced.Infection through the roots does not always coincide with cyst infection but it often does.The field above has a history of relatively high cyst pressure.Though the variety grown was cyst resistant that alone will not stop juvenile cysts from penetrating their needlepoint proboscus through the root membranes.These wound sites can serve as portal of entry sites for fusarium solani fungi to penetrate and block off the phloem and xylem network causing the plants upper leaves to starve from the lack of water and assimilates.
Notice how interveinal chlorosis of the upper leaves occurs as fusarium solani fungi infect the roots and block off the plants phloem and xylem.
This shot shows the initial appearance of leaves as SDS gains a foothold in the roots.
This shot shows more clearly how leaf tissue between the veins dies completely as SDS infection increases in the lower stem and roots.
A well trained agronomist can ID Sudden Death Syndrome in the field but for the average individual you are probably best to submit plant samples to a lab for conclusive analysis.SDS by just leaf apperance cannot be distinguished from BSR ( Brown Stem Rot )The key to diagnosing SDS is the grey brown oily appearance that the lower stem and root crown display when they are cut open.You'll note the grey brown oily appearance in the photo above.( PHOTO IS COMPLIMENTS of SUZIE DEVOLDER - Chatham Diagnostics Lab )
This shot shows clearly how an infected SDS plants lower stem and root crown appear alongside a healthy plants lower stem and root crown.( Top stem is infected while the bottom stem is from a healthy plant )The key then to determining if SDS is the culprit is to slice open the lower stem and root crown and look for a grey brown oily appearance. ( PHOTO IS AGAIN COMPLIMENTS OF SUZIE DEVOLDER - Chatham Diagnostics Lab )