Horticulture: April 2005

As a horticulture consultant, I'm keenly aware of the ever-increasing diversity of the agricultural landscape in the Noble Foundation's service area. Many of our client cooperators are establishing alternative crop enterprises such as small fruits, including grapes and blackberries, peaches, pecans and market gardens to supplement their incomes.

With increased crop diversity, there is an accompanying increased risk of crop injury due to herbicide drift. Drift damage to alternative crops is a common occurrence in southern Oklahoma and north Texas, where herbicides are routinely applied to pastures and rangeland. I'm personally aware of several incidences where herbicide drift damaged vegetable plantings during the 2004 growing season.

A common symptom of 2,4-D drift damage to grape ? a fan shaped leaf with small puckered spots between the veins.

While it is ultimately the responsibility of the applicator to prevent off-target damage by an herbicide, the grower of alternative crops also has responsibility in drift management.

Dr. Case Medlin, Extension weed specialist with the Plant and Soil Sciences Department at Oklahoma State University, has developed a list of best management practices for preventing herbicide drift onto susceptible crops. A few of these practices relevant to alternative crop producers include:

1. Growers of sensitive crops should communicate to their neighbors, nearby commercial applicators, pesticide dealers and landowners the exact locations of their susceptible crops that may be affected by off-target movement of herbicides. They should be especially mindful of neighboring wheat fields, pastures and/or rangeland that may receive applications of hormone-type herbicides (2,4-D, 2,4-DB, dicamba, picloram, etc.)
    
2. Growers should also communicate to the county or state highway department that may spray nearby roadsides with hormone-type herbicides.
    
3. When practical, growers should locate sensitive crops away from property borders and away from areas that are likely to receive applications of hormone-type herbicides. For example, if the field where you desire to plant vegetable crops borders pasture or rangeland, determine whether the pasture/rangeland owner plans to spray in the upcoming growing season. Typically, native range is not sprayed every year, but every other or every third year, therefore you may be able to work with your neighbor to coincide your rotation to that field in a year that he/she will not be treating the grass.

One of the keys to continued crop diversity and the economic prosperity of area agriculture is keeping an open line of communication among alternative crops growers and pesticide applicators.

For a comprehensive list of best management practices for preventing herbicide drift onto susceptible crops, contact Case Medlin at (405) 744-9588 or visit http://www.weedscience.okstate.edu/.