Scouting Notes - May 2007

Know how pesticides move on, in plants. Understanding how an insecticide moves or doesn’t move in a plant is critical to insecticide/miticide selection and proper application, reports Michigan State University Extension IPM educator Dean Krauskopf.

For contact materials to be effective good coverage is critical because any surface not covered isn’t toxic, including new shoots and leaves in the growing tip.

Systemic products move within the plant and are applied to the growing medium. They take time to move up to the new shoots and control doesn’t happen until the material is present where insects or mites are feeding. The woodier the plant, the more slowly systemics move, and the amount of material present in the new shoots is very small.

Translaminar materials don’t have surface residues but move short distances into the plant tissue where a reservoir of active ingredient remains for a period of time providing longer control. Thorough coverage is very important.

For more: Dean Krauskopf, (248) 347-0269; www.ipm.msu.edu.

Calibrachoa takes a hit. Cornell University entomologist Dan Gilrein reported at this year’s Society of American Florists’ Pest Management Conference that calibrachoa is being attacked by tobacco aphid, Myzus nicotianae, which some growers reported has been more difficult to control than other aphids.

In preliminary studies by Gilrein, two spray applications of Aria, Marathon and Scimitar were effective. Orthene, which is not labeled for this crop, was effective with just one treatment.

Calibrachoa is also susceptible to tobacco mosaic virus. In February, Fischer USA requested that growers discard cuttings of Callie Orange received from its propagation facility in Ethiopia . Stock plants there were discovered to be infected with tobacco mosaic virus. Callie Orange cuttings from its Portugal and China facilities were determined to be virus free.

{sidebar id=1}

For more: Dan Gilrein, (631) 727-3595; dog1@cornell.edu. Fischer USA, (800)344-7862; www.fischerusa.com.