UGA\u00a0pecan specialist Lenny Wells recently updated us on the effect of\u00a0pecan orchard air flow\u00a0and elevation on\u00a0scab control.\u00a0\u00a0See comments below.<\/p>\n
“One of the most often over-looked factors I see regarding\u00a0production problems\u00a0in pecan\u00a0is a consideration of the site where the orchard was planted. Not long ago, I spoke with a grower who had been on a very good fungicide program. His scab control was excellent in most orchards but in a few orchards scab was a problem. As it turns out, most of those orchards in which scab was becoming a problem were smaller orchards of 30 acres or less and surrounded by woods. \u00a0The surrounding woods hold moisture in the area and block wind, limiting airflow in the orchard. Sounds too simple to be the source of the problem, but I\u2019ve seen it many times.<\/p>\n
Aside from air flow, elevation is an important factor to consider as well. Most growers know this but too often fail to accept it as a serious issue in their own orchards. Scab-susceptible cultivars planted in low lying areas often have serious problems with scab. This can be readily observed by comparing scab severity on trees on low and high ground within the same orchards. Invariably those trees at the bottom of a slope or in a low-lying hole will have more scab problems than those on the higher ground.<\/p>\n
A scab susceptible cultivar planted in a low-lying area surrounded by woods is a recipe for\u00a0disease problems no matter what fungicide program you are using. \u00a0Certain conditions may cause the climate in one zone within an area to differ from the surrounding areas. I believe this is one reason we see such a wide spectrum of disease control from one area to another with basically the same fungicides being used. The scientific term for this is \u201cmicroclimate\u201d and it varies greatly when comparing, for example, Albany, Georgia with Ft. Valley or Waycross with Americus. We often talk about the differences in the amount of rainfall in these locations. But, middle Georgia is on much higher ground than that of Southwest or Southeast Georgia. As a general rule, I would say that sites with an elevation of 300\u2032 or more<\/strong> <\/em>will have an easier time producing pecans. I never realized how much difference there was in elevation from one location to another in South and Central Georgia.\u00a0This map shows some of the variation in elevation across the Georgia pecan belt.<\/p>\n
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