1st - Shot Hole.

I grow Prunus 'Otto Luyken' for a wholesale nursery both in field and container production. We will have fields of identical crops of Otto's, propagated at the same time from the same stock plants, all watered the same, fertilized the same, sprayed the same, pruned the same, etc... One field can be perfect and the field next to it can have heavy shot hole. I have sent plant samples into testing labs and they reply saying that they have no idea why they have the shot hole. I know that it can be a result of environmental stress but since the plants are all treated the same I am disregarding that. I regulary spray the plants with all of the recomended fungicides. What are your thoughts on what causes shot hole and what do you do to prevent it? The one thing I always end up thinking back to is that in every commercial landscape I have seen I have never seen any shot hole. What is causing these plants that are planted in the landscape to be fine? They are not sprayed w/ fungicides, usually only fertilized once a year if at all, and probably are under watered due to inadequate irrigation systems. I am about to the point of trying to purposely neglect my production plants and treat them like plants in landscape. What do you use for preventative and/or curative fungicides?

2nd - blooms

One of my biggest labor costs is removing the spent flower spikes from the Otto's in the spring before digging and shipping from the previous fall's flower production. I am going to try this year to fertilize in the late summer with a low phosphorus fert to hopefully discourage the formation of the flowers. I usually fertilizer twice a year with a slow release fert, once in March/April and again in July. By July will the plant have already begun to internally initiate the formation of the flowers or will this be early enough to discourage the flower growth? Is there anything I can spray to discourage the flowers?

Sorry to be long-winded.

Thanks,

Travis