In this issue
§ Tobacco mosaic virus
§ Contact, systemic and translaminar: How insecticides move in plants
§ Grower support for Section 18 registration of Gentry
§ Visit the new MSU annual trial gardens website
Tobacco mosaic virus (TMV) has a very wide host range including petunia, calibrachoa, lobelia, impatiens, chrysanthemums, geraniums and tomato. Symptoms caused by TMV vary greatly depending on the host. Symptoms may include, yellowing of the foliage, necrotic leaf spots, mosaic symptoms, stunting and leaf distortion. (View images)
Unlike some of the other common viruses of ornamentals, TMV is not vectored by insects. The virus can be spread by sap, through vegetative plant production and through mechanical means. Smoking should not be permitted in production areas because tobacco products can carry TMV.
Fungicides are not helpful in controlling plant diseases. Once plants are infected with a virus, they can not be treated to eradicate the virus. Infected plants should be removed and destroyed. Identifying infected plants can sometimes be challenging. MSU’s Diagnostic Services lab can test samples for TMV with ELISA testing. Samples should be submitted with next day delivery and should not be mailed on a Friday. Overnight delivery is recommended because several samples mailed recently with slower delivery options were frozen when they arrived at the lab.
Click here (www.pestid.msu.edu) to learn how to submit a sample, or contact me (517-355-3504) if you have any questions about submitting samples or the testing procedure.
|
Begonia |
Geranium |
Osteospermum |
|
Calibrachoa |
Impatiens |
Petunia |
|
Chrysanthemum |
Lobelia |
Tomato |
|
Gazania |
|
Verbena |
Understanding how an insecticide moves, or doesn’t move, in a plant is critical to insecticide/miticide selection and proper application. Contact materials cover only the plant’s surface and insects or mites must directly contact the active ingredient for control. Good coverage is important – any surface not covered isn’t toxic, including new shoots and the newest leaves in the growing tip.
Systemic materials, on the other hand, move within the plant; applied to the media they will move throughout the entire plant, including new shoots. However, systemics take time to move up to the new shoots and control doesn’t happen until the toxic material is present where the insects or mites are feeding. The woodier the plant, the more slowly systemics move. In very woody stock plants, the material may not move into the shoots at all. One solution is to spray systemic materials on the tops of plants (Marathon II). Remember that insecticides tend to move upward in the plant, not downward; there will be little control of insects or mites below where the application was made.
Another problem with systemics is that the amount of toxic material present in the new shoots is very small. Aphids may concentrate enough toxic material in the sap they feed on to be killed, but chewing insects may not get enough to be controlled. Translaminar materials don’t have surface residues but move into the leaf where a reservoir of active ingredient remains for a period of time providing longer control. Don’t confuse translaminar with systemic – translaminar materials move only short distances not through the entire plant. Thorough coverage is still very important.
Most insecticides today are contact materials, some are
systemic and a few (imidacloprid and similar
materials) are all three. Check the label for more information. Thanks to Dr.
Ray Cloyd,
Liverwort control remains a top concern for greenhouse
growers in
It is important to note that EPA is only allowing two weeks, until February 22,
2007, for comments to be submitted, so we need to move fast. Also, please be
sure that every comment submitted be identified with the docket number EPA-HQ-OPP-2007-0028.
Comments can be submitted in various ways:
§
Via the Internet:
Federal Rulemaking Portal at: http://www.regulations.gov . Then
follow the online instructions for submitting comments.
§
By mail
to: Office of Pesticide Progams Regulatory Public
Docket (7502P), Environmental Protection Agency, 1200 Pennsylvania Ave. NW,
Washington, DC 20460-0001.
§
By delivery
(e.g., FedEx) to: OPP Regulatory Public Docket (7502P), Environmental
Protection Agency, Room S-4400, One Potomac Yard (South Building), 2777 So.
It is important that the growers voice their support for this process. If you have any questions, please let me know.
Dr. Norm
Lownds, coordinator of the annual trials at
Each year, MSU evaluates the landscape performance of over 1,000 cultivars of annual plants. In the past few years, the gardens staff has also evaluated plant performance in large containers.
The MSU Annual Trials website contains searchable databases,
where you can search each year’s entries by genus, series, cultivar, company or
rating. The database includes unbiased notes and photos of the trials. The top
performers of each plant species are listed and grouped into the
best-performing plants from seed, vegetative cuttings and in containers. In
addition, the “Spartan Selects” identify the best-of-the-best plants in our
growing conditions in
Plan to visit the trial gardens at MSU this summer to make your own observations of plant performance. You’re also welcome to participate in the MSU Garden Plant Showcase scheduled for Wednesday, August 7, 2007. Stay tuned for more details.