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Bacteria and Freeze Damage

Freeze damage and the presence of pathogens in the orchard can apparently be linked.    George Sundin  and Nikki Rothwell at the Michigan State University Extension, Department of Plant, Soil and Microbial Sciences published at article entitled, “ Bacterial canker, ice nucleation, frost injury and blossom blast in sweet cherries”, outlining how in this example, a bacterial pathogen worked in tandem with frost events to cause or further damage in a prunus species.

The phenomenon occurs when bacterial cells act as nucleation sites within the flowers. The presence of the bacteria facilitates freezing which in turn allows the plant tissue to be damaged, and thus permits the pathogen to invade the plant tissue more effectively. An ingenious, if insidious maneuver.  How effective the process is depends upon the temperature (the cooler it is, the less bacterial cells are necessary to cause freeze damage). The bacterium acts, in a way as a catalyst.

The entire article can be read here.


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Pears and Fireblight

erwinia amylovora on pear (image : Ninjatacoshell)

No demon could ever conjure up a worse fate for the pear grower than that manifested in the fireblight bacterium. Erwinia amylovora. It nearly sounds like the latin words a midieval priest might give such a sordid beast.

Fireblight can affect a host of species, including amelanchiers, hawthorns, apples, but pears so often seem the worst molested. There is no cure for the infected area once it is attacked, the protocol is to cut off or cut out the infection  and then some. It is a more successful strategy to keep it from occurring in the first place. Following are several strategies to lessen your chances of encountering this unwanted visitor. More to come…