What is in this article?:
- The proper identification of winged-aphid species found on leafy vegetables in the desert is important for cost-effective pest management.
- Rainfall and higher humidity favor the development of downy mildew in desert-grown lettuce and suggest increased inspection of fields for the disease.
- Herbicide codistillation is when a herbicide evaporates or changes from a liquid to a vapor with water.
‘Lift-off’ or codistillation of GoalTender and Goal 2XL (Oxyfluorfen)
By Barry Tickes, UA Area Agriculture Agent
Herbicide codistillation is when a herbicide evaporates or changes from a liquid to a vapor with water. This can occur from soil, water, or plant surfaces and can be responsible for the substantial loss of some herbicides.
When codistillation occurs with GoalTender or Goal2XL, the concern is not herbicide loss but crop injury.
Codistillation can occur with several herbicides. It is affected by many factors including temperature, moisture, organic matter, soil pH, and other variables.
In general, codisillation is greatest when temperatures, moisture, and pH are high and organic matter is low.
One of the herbicides used in this region most affected by codistillation is Eptam. A study conducted several years ago in Brawley, Calif. found more than 80 percent of the Eptam applied in irrigation water was lost by codistillation. Most of this was from the soil after it had reached the field.
In our trials, we have found codistillation may help GoalTender and Goal 2XL (oxyfluorfen, also sold as Galligan, Oxi Flo and others) kill weeds but it also can increase crop injury. Goal can move into plants in the vapor phase once it has lifted off and weed control and crop injury are enhanced. We have seen this when Goal is chemigated through sprinklers.
Goal is primarily a contact-type herbicide and moves little in the plant. It is rare for contact-type herbicides to work better when overhead water is applied but this seems to be the case with this herbicide.
“Lift-Off” or codistillation of Goal has earned it the reputation by some as a herbicide that is prone to causing injury to sensitive crops grown in adjacent fields. In many cases, this potential is exaggerated.
Lift-Off of Goal differs from the usual off target drift that can occur with other herbicides. In this case, it is the movement of the herbicide with water vapor. Moisture must be present and must evaporate. The vapor normally stays in the field. It is common for a band application to the furrows, for example, to move across the bed top. Significant movement out of the field normally only occurs with wind.
GoalTender is not as volatile as Goal 2XL and is less prone to codistillation.
Contact Tickes: (928) 580-9902 or firstname.lastname@example.org.
Row cover video
By Marco Pena, UA Research Specialist
Some organic growers use polypropylene fabric row covers as insect barriers and others use it for frost protection.
John Palumbo is conducting research at the Yuma Ag Center with this material for insect control and in some cases the fabric is used as a cage. Plots are infested with Bagrada bugs to evaluate the damage that could occur to the crop.
The following video shows the procedures to establish a trial:
Contact Pena: (928) 782-3836 or email@example.com.