No. 14/August 29, 2017
Tubakia Leaf Spot
Tubakia leaf spot is a fungal disease caused by the pathogen, Tubakia dryina. It is a common sight on oak trees late in the summer. All oak species are susceptible to this disease, but those within the red oak group are more commonly affected. This leaf spot is often associated with stressed trees, especially Pin oaks with symptoms of iron chlorosis. While the disease is mostly found on oak trees; other potential hosts include maple, hickory, chestnut, redbud, ash, black tupelo, sourwood, sassafras and elm.
Pollinator Conference
The second national conference on 'Protecting Pollinators in Urban Landscapes' will be held October 9 - 11 in Traverse City, Michigan, giving landscape professionals a unique opportunity to hear some of the best experts in the country on this topic. Arborists, city foresters, lawn and landscape professionals, public or private garden managers and golf course superintendents will all benefit. The program is packed with gems for landscapers and arborists, starting with an entertaining keynote address by Lawrence Packer, professor and author of "Keeping the Bees" and "Bees: A Close-up Look at Pollinators Around the World."
Armyworm
Large numbers of adult armyworms are being found in the Midwest. These moths have reddish-brown wings, and a wingspan of about two inches. The dark brown moths with one-and-one-half inch wingspans that are very common now are green cloverworm adults. Their larvae feed primarily on legumes.
Azadirachtin Recall
Four organic insecticides were recently found to be contaminated with several synthetic insecticides by the Oregon Department of Agriculture (ODA). ODA is now working to identify the source of contamination for these insecticides. All found contaminants are insecticides, and their presence in treated plant products could lead to unknown health effects for consumers and major economic losses for organic and other growers. If organic growers used these adulterated organic insecticides, they could end up with illegal residues on their agricultural products, potentially preventing them from marketing their production.