Monitor root health and test growing media of garden mums. Take random samples of plants out of their pots and examine roots carefully. The roots tell a lot about overall plant’s health, often before the top growth shows symptoms. Signs of poor root health are blackened or rotted roots or the lack of roots, especially young feeder roots. Diseased roots will not take up fertilizer.
The familiar imported cabbage worms adults can be seen fluttering above ornamental cabbage and kale. The adult is a white butterfly tinged with yellow on the underside of its wings.
The caterpillar of the sunflower moth, Homoeosoma electellum, damages the flowers of echinacea and sunflower. Newly hatched larvae are pale yellow, but darken to shades of brown or purple with longitudinal white stripes. Look for mats of webbing on the face of flowers for signs of larval feeding. The injury caused by larval feeding can lead to Rhizopus head rot.
Note: The 2015-2016 New England Greenhouse Floriculture Guide will contain a new section “Protecting Bees and Pollinators from Pesticides”. Contributors to the new section are Dr. Richard Cowles, The Connecticut Agricultural Experiment Station, Dr. Raymond Cloyd, Kansas State University, Dr. Kimberly Stoner, The Connecticut Agricultural Experiment Station, Dr. Lois Berg Stack, University of Maine and me. The new guide will be available November 5&6 at the Northeast Greenhouse Conference. Tina
Bob Luczai, Mass Flower Growers Association reported Impatiens downy mildew last week in Dover, Wellesley and Sherborn, MA in landscapes, the first reports in MA in 2014 that I am aware of.
Growers and retailers have been asking if the disease is still a problem and should they begin to grow garden impatiens next spring. Customers continue to want to plant garden impatiens, so demand (and likely a little pressure) continues. Because of this, some growers started producing garden impatiens this season (2014) when they did not produce them last year (2013).