Greenhouse and nursery growers in California can add Avelyo fungicide to their disease management program. With the successful registration in California, Avelyo is now available to growers in almost all states, except Hawaii, New York and Maine.

Avelyo is a broad-spectrum fungicide introduced by BASF in 2021. Avelyo contains mefentrifluconazole, which is a demethylation inhibitor or DMI fungicide (FRAC Group 3). Avelyo is registered for use against multiple fungal diseases in greenhouses, interiorscapes, nurseries and Christmas tree farms. This product isn't registered for use on residential ornamentals anywhere in the United States.

Avelyo can be applied as a foliar spray to preventively control Antharacnose, leaf spots, stem blights, powdery mildew, scabs and rusts on ornamental plants. Spray application rate ranges from 8 to 10 fl. oz. per 100 gal. for rusts and 3 to 5 fl. oz. per 100 gal. for other diseases. Avelyo can also be drenched at 2 to 3 fl. oz. per 100 gal. against root and crown diseases, such as Cylindrocladium and black root rot.

Avelyo has a long residual activity and rapid rainfastness and it's safe on plant species tested so far (see a previous issue of this newsletter summarizing the finding).

Contact your local BASF representative or go HERE for more information on Avelyo fungicide.

Agdia, the provider of many plant pathogen testing kits and services, has added a new test kit for tomato mottle mosaic virus (ToMMV) to its AmplifyRP XRT platform.

A previously launched test kit allows for the detection of another important virus, the tomato brown regose fruit virus (ToBRFV). For those who aren't familiar, AmplifyRP XRT is a portable, easy-to-use device that can help growers detect certain fungal, viral, phytoplasma and bacterial pathogens in-house and in 30 minutes or less. The AmplifyRP XRT device is much smaller and cheaper to operate than a typical PCR machine.

ToMMV and ToBRFV are members of the Tobamovirus and among the most important viruses of tomato. While the word “tomato” is in its name, ToBRFV can also infect peppers.

ToMMV was first found in Mexico in 2013 (the sample was actually collected in 2009) and has since spread throughout the world. ToBRFV was first found in Jordan in 2016. It spread to Mexico (a major fresh tomato exporter to the United States) in 2018, which placed regulators and scientists in the United States on high alert. Infestation of ToBRFV in the United States was first detected in 2019 and since then have been reported in several incidences. Some of the infestations were eradicated, but the status of others is a bit unclear.

Both ToMMV and ToBRFV have the ability to bypass major resistance mechanisms bred into tomato (or pepper) cultivars and can be transmitted through seeds and physical contact. These characteristics make them extremely difficult to manage. There's currently no effective pesticide treatment. Management centers on sanitation, hygiene and disinfestation (see a previous issue of this newsletter on disinfecting ToBRFV), use of virus-free seeds and seedlings, and removal of bumblebee hives (the bees can also transmit the viruses after contacting infected plants).

Agdia’s test kits for ToMMV and ToBRFV are highly specific to these viruses. They can be used to detect the presence of the viruses in seeds and leaves. Seeds and seedlings can be tested before they're planted, so infection isn't introduced into the production. Samples can be collected throughout the crop cycle, and then processed and tested in house, thus allowing growers to respond to infection quickly.

See Agdia's offering of pathogen diagnostic test and services HERE.

Y’all are probably quite familiar with Phytophthora ramorum, which is the causal agent for sudden oak death, ramorum leaf blight or ramorum dieback on several plant species in forests and nurseries. Sudden oak death was first detected in 1995 in Marin County, California. Currently, full or partial quarantine is imposed on several coastal counties in California and Oregon. Nurseries in the quarantined counties are allowed to ship proven hosts and associated plants if these plants are tested negative of the pathogens under a compliance agreement.


The rhododendron cultivar Unique, grown in a nursery, showing necrotic lead spots along the margins of leaves. (Photo credit: Jennifer Parke. Source: Pafici Northwest Pest Management Hanbook.)

USDA APHIS recently released an updated list of proven host plants (78 genera and species) and associated plant species (110 genera and species). The list includes 30 and 51 new proven hosts and the associated plants, respectively. The updated list will be used for the next compliance inspection.

Click HERE for more information on ramorum blight and the quarantine regulations. Click HERE for information on management.

There are two webinars I want to introduce to ya'll for the first part of December.

The first webinar is on December 1 at 1:00 p.m. Eastern/noon Central. Troy Buechel of Premier Tech will join GrowerTalks' very own Chris Beytes to talk about how biological active ingredients in potting mixes can help plant growth and improve your bottomline. Register for this webinar HERE.

What in the world are biological active ingredients, you ask? Well, biological active ingredients are living microbes that are added to potting mixes. These microbes may include biofungicides (such as Bacillus pumilus) or mycorrhizal fungi (such as Glomus intraradices). These microbes colonize plant roots and promote disease prevention, and plant growth and health benefits.

Another webinar is part of the American Floral Endowment's (AFE) Grow Pro series. Among all the diseases, I have the poorest understanding of foliar nematodes and viruses. (It took me some research time before I could write with confidence the previous segment on ToMMV and ToBRFV.) I’m glad to see a continuing educational opportunity from AFE on viruses of flower crops. Click HERE to register.

The webinar is scheduled for December 20 at 1:00 p.m. Eastern/noon Central and is sponsored by Ball Seed and Syngenta Flowers. John Hammond, research plant pathologist with the USDA Agricultural Research Service (ARS) in Beltsville, Maryland, will talk about viruses that are common in flowering plants, and their symptoms and transmission. John will try to reduce concerns for latent plant viruses, which are the viruses that are present in plants, but cause no ill effects or severe symptoms.

By the way, I’ll see some of you in person at the Great Lakes Expo in a couple of weeks. I’ll have two talks on December 7: one on the identification of the Big Fives (mites, thrips, whiteflies, aphids and mealybugs), and another on new insecticides and miticides that have been introduced in the past three years. Believe it or not, I’ve never been to Grand Rapids, so this is a nice chance for me to visit the city and growers in the area.