Weather conditions affect spray drift Last week I wrote about drift prevention and discussed equipment setup. Whether the sprayer is an aircraft or ground rig, it must be properly equipped.

Another factor is common sense and a good understanding of the herbicide you are spraying. Some like to define drift as any movement of spray off the target area. While every effort must be made to keep 100 percent of the spray on the target, it is not a perfect world. Often a decision must be made that if the spray is going to move a little, what direction can it move and not hurt anything.

Some crops and some situations are far more sensitive than others. To me, situations that involves a residence, people, or home garden are the most sensitive.

When it comes to crops, some are ultra-sensitive. These include Facet to tomatoes, 2,4-D to cotton and glyphosate (Roundup, Touchdown and generics) to seedling corn, seedling rice and rice during the reproductive growth stages. A misapplication can result in these crops being affected over considerable distances. With these, it is often more difficult to determine where a drift may have come from. When this happens, it is usually the herbicide that gets regulated, rather than enforcement action being taken on some for misuse.

Facet is in the court system now. Regardless of the outcome of the cases, that is not good. Prior regulations have eliminated 2,4-D as a rice herbicide in many areas.

In 2000, calls about potential glyphosate drift were far too common to this specialist. In fact, I had more calls about this than any other topic.

It is my understanding that a bordering state has restricted the use of glyphosate by aircraft sprayers during the spring burndown season. Not all of my glyphosate calls involved aircraft sprayers, but this could be a severe restriction for growers.

In every case where we have had major problems through the years, it has been with an extremely important herbicide for a given crop. Of course, it is only common sense that the more usage a product receives, the greater the chance for a mistake to be made. The restrictions on 2,4-D through the years have hurt. The Facet situation has hurt.

With more acreage going into reduced tillage systems each year, how are folks who can't have glyphosate applied by aircraft in a wet spring going to manage emerged vegetation? However, if we continue to affect others, unwanted and often unnecessary restrictions can occur.

Some may say, "Doc, you just don't know what it is like out there in the real world trying to get things done." Sure I do. We have to spray sometimes when the wind is blowing. The risk in my operation, with small plot spray equipment, is not affecting a neighbor or neighboring crop, but rather cross continuing adjacent plots. Individual plots in a study are side by side. Therefore, we can not stand much spray movement.

Conditions are not always ideal when we have to spray. However, we also have to make the decision when too much spray movement is occurring. At that point, the only solution is to stop and wait.