Key times for alfalfa insect activity
In alfalfa, monitoring should begin when the crop begins to regrow in early spring. Early infestations of alfalfa weevil can be seen in March if conditions are warm. The potential for significant damage by this pest, however, does not occur until late April to mid-May. Monitoring from the beginning of spring growth to late April should involve only a quick visual inspection for signs of feeding. Monitoring can be terminated when potato leafhopper populations begin to decline around the middle of August.
|Attacks New Seedlings|
|Emergence to First Cutting:|
|Black cutworm||Garden symphylan|
|Potato leafhopper||Pea aphid|
|Grasshoppers||Plant bug spp.|
|Spotted alfalfa aphid|
|Attacks Established Stands and Fall Seedings|
|Second Through Fourth Cuttings:|
|Potato leafhopper||Alfalfa blotch leafminer|
|Pea aphid||Variegated cutworm|
|Spittlebug||Clover leaf weevil|
|Clover root curculio||Grasshoppers|
|Plant bug spp.|
Reference: Table 2.1-3, The Agronomy Guide.