Around the state, there have been a lot of alfalfa fields either sprayed or harvested, in the pursuit of controlling alfalfa weevil and making the first cutting of the year a quality one. If you have a field that hasn’t been treated or scouted yet, it is still worth the effort to assess the field prior to first cutting.
The following table indicates the average alfalfa height and alfalfa weevil population for the couple of fields scouted in each county for the week of May 7th-May 13th.
|
County |
Alfalfa Height (inches) |
Average Larvae Count per Stem |
|
Auglaize |
20-28 |
0.2 |
|
Defiance |
19-24 |
0.03 |
|
Mercer |
26-32 |
0.2 |
|
Paulding |
25-28 |
0.17 |
|
Ross |
14-31 |
0.06 |
|
Wayne |
18-32 |
0.4 |
Every county scouted this week saw a reduction in the alfalfa weevil population as spray controls and harvesting diminished the overall pest presence. As the window of concern about alfalfa weevil begins to close there are a few things to keep in mind. If a spray control is used be sure to follow the pre-harvest interval that is required. If there was a substantial alfalfa weevil population prior to first cutting be sure to scout for feeding on alfalfa regrowth 4-5 days after harvest. Alfalfa weevil feeding can significantly slow regrowth and decrease alfalfa production.
If you would like to learn more about the scouting process, reference the article written earlier this year “Scouting Early Alfalfa Weevil Activity” and this 5-minute forage team video “Alfalfa Weevil Scouting”. If you have any questions reach out to an author or your local extension office.