Joanne Whalen, Extension IPM Specialist; jwhalen@udel.edu
Asparagus
The first asparagus beetles are now active. Since harvest has started, be sure to check for asparagus beetles laying eggs on asparagus spears. As a general guideline, a treatment is recommended if 2% of the spears are infested with eggs. Since adults will also feed on the spears, a treatment is recommended if 5% of the plants are infested with adults.
Cabbage
Imported cabbage worm (ICW) and diamondback moths (DBM) can be found laying eggs in recently planted fields. Be sure to begin scouting fields within a week of transplanting for recently hatched larvae. As a general guideline, a treatment is recommended if you find 5% of the plants infested with larvae. If DBM is the predominant species, be sure to select an insecticide for this insect pest since it can be difficult to control. Materials labeled on DBM include Avaunt, Coragen, the Bt insecticides, Proclaim, Rimon, Radiant, Synapse, Vetica, and Voliam Xpress.
Peas
This week’s weather has been favorable for aphid development so be sure to sample for pea aphids as soon as small seedlings emerge. On small plants, you should sample for aphids by counting the number of aphids on 10 plants in 10 locations throughout a field. On larger plants, take 10 sweeps in 10 locations. As a general guideline, a treatment is recommended if you find 5-10 aphids per plant or 50 or more aphids per sweep. In general, aphid development is favored by cool, dry weather which slows beneficial activity but is favorable for the development of aphids.