UTAH PESTS News Utah Plant Pest Diagnostic Laboratory and USU Extension Vol. 11, Spring 2008 Bee Healthy in Utah Bee health is a hot topic in the ento- mology world, and What’s Inside for anyone depend- ing on pollinating Onion Powdery Mildew insects. Most likely many of you have Snow Mold on Turf heard about wide- spread honeybee Carpenter Ants colony death in the United States. The Cankerworm Watch collective term for this poorly under- Preventing Pesticide stood phenomenon Resistance is called Colony Soil and Tissue Fertility Collapse Disorder Testing in Orchards (CCD). Waugsberg, http://en.wikipedia.org/wiki/Image:Bienen_auf_Wabe_2.jpg Waugsberg, Calendar of Events, Originally described News, Publications, and in North America in Web Sites of Interest late 2006, CCD is also being observed News Highlights in Europe and possibly in Taiwan. UTAH PESTS NEW To date, there is FACT SHEETS no single cause to The following can be blame for CCD. But found on our Web site: there are a num- Alfalfa Stem Nematode ber of developing theories attempting Beneficial Insects: to explain why hon- Beetles Mantids eybees are suddenly True Bugs dying, including mal- nutrition, pathogens, Black Grass Bugs parasites, pesti- http://en.wikipedia.org/wiki/Image:Drinking_Bee.jpg Bartosz Kosiorek, Human Lice cides and geneti- A normal honeybee hive (above) has capped brood and many adult workers. Fleas cally modified crops. Honeybee drinking nectar (below). CCD could likely Russian Wheat Aphid be a combination abandon a hive until the brood emerges), and Utah Home Orchard of several factors available food stores. In some cases, the hives Pest Management Guide contributing to the rapid decline of bee colony (Revised) appear relatively healthy and include an ac- health. When a honeybee hive crashes, several tive queen, but there just aren’t enough adults Wheat Stripe Rust simultaneous symptoms associated with CCD present in the hive to take care of the immature are often evident, such as a lack of adult bees in brood. the hive, capped brood (bees do not normally www.utahpests.usu.edu Continued on next page Bee Healthy in Utah, continued from page 1 UTAH PESTS Domesticated honeybees in the United sampling for pathogens and parasites. Two of States were introduced from Europe in the the most important problems affecting bee Staff 19th Century. Since 1971, the United States health in Utah include the varroa mite and a has seen a gradual decline in domesticated bacterial disease called American foulbrood. honeybees and a striking decline in native, In 2007, over 3,400 colonies were inspected Diane Alston wild honeybees. Although the number of by members of UDAF. Overall, varroa mites Entomology Specialist beehive colonies are decreasing each year, were prevalent, but disease incidence was [email protected] there is still a huge demand for pollinating low (2.6%). Beekeepers actively try to con- 435-797-2516 insects in agriculture and horticulture. Hon- trol mites and harmful bacteria so that the eybees are responsible for about one-third hives are in optimal health. Ryan Davis of pollinated crops in the United States, with Arthropod Diagnostician total production values exceeding $15 billion The exact reason for CCD is still unknown. [email protected] each year. Almonds, for example, are worth Fortunately, CCD has not been detected in 435-797-2435 over $1.5 billion and depend on honeybees Utah beehives. The Colony Collapse Disor- for pollination. Honeybees also pollinate der Working Group, primarily based at Penn Kent Evans apples, blackberries, cherries, cucumbers, State University, is leading the research to Plant Pathology Specialist peaches, raspberries and watermelons. In stop CCD and improve bee health. To learn [email protected] Utah, the honey industry is worth more than more about CCD, visit http://en.wikipedia. 435-797-2504 $1 million each year. org/wiki/Colony_Collapse_Disorder. Local beekeeping clubs can also provide specific Erin Frank The Utah Department of Agriculture and information for colony health, pest control, Plant Disease Diagnostician Food (UDAF) monitors for bee health every and marketing bee byproducts. [email protected] year. Bee inspectors not only survey for 435-797-2435 the number of active hives within the state, but also assess the health of each colony by -Erin Hodgson, Extension Entomologist Erin Hodgson Entomology Specialist [email protected] NEWS from THE diagnostic LAB 435-797-5689 UPPDL Hires New Plant Disease Marion Murray IPM Project Leader Diagnostician Editor, Utah Pests News [email protected] Erin Frank grew up in northeastern Colo- Erin will process all plant disease submissions 435-797-0776 rado and attended Colorado State University and also provide customized management where she completed her Bachelor of Sci- guidelines for the Utah Plant Pest Diagnostic ence degree in 2004. Her major was Soil and Lab. Utah Plant Pest Crop Science with a concentration in Plant Diagnostic Lab Breeding and Genetics. In 2005 she moved BNR Room 203 to Manhattan, Kansas, where she began Utah State University 5305 Old Main Hill working on her Master of Science degree Logan, UT 84322 at Kansas State University. Her research in- volved studying gene expression of the prai- rie grass big bluestem in response to drought Utah Pests News and rust infection. She also had a second is published quarterly by the project which involved molecular studies of UTAH PESTS staff. a fungal isolate found in bison saliva. Erin defended her Master’s thesis in June 2007 utahpests.usu.edu and received her Master of Science degree in Plant Pathology. She continued working in the same lab finishing up her other projects USU Extension welcomes Erin Frank to the before moving to Logan in January. UPPDL. www.utahpests.usu.edu Utah Pests News - Spring 2008 - page 2 PLANT pathologY NEWS AND information Onion Powdery Mildew – Should We Worry? Although considered a minor disease Early infection symptoms appear as on onions, powdery mildew is show- whitish lesions on leaves and later, ing up in more onion fields in the when conditions are conducive, the western United States. The disease fungus will produce visible myceli- does not appear to be of major con- um (Figure 1) with prolific num- cern at present. In Utah, occurrences bers of spores (Figure 2). Primary of the disease have been more notice- spores, called conidia, are pointed able and prevalent in the latter part of or lanceolate (Figure 3) and sec- the season, after crops have matured. ondary spores are more cylindrical Consequently, crop yields have not and rounded on the proximal ends been significantly affected. (Figure 4). While there are no recommenda- The pathogen can survive from one tions for chemical control, there are season to another in crop resi- reports that some onion cultivars are dues, serving as inoculum to infect more susceptible than others. I am susceptible crops the following unaware of any onion breeding pro- season. It can also be introduced gram actively screening for resistance into an area on infected planting to the disease; however, there are stock. Keep your eyes peeled for likely onion breeders doing prelimi- this disease. How ever you slice it, nary investigations. my belief is that powdery mildew on onion is not worth shedding Onion powdery mildew is caused by tears over just yet. Figure 1. Visible mycelium of the powdery mildew the fungal pathogen, Leveillula taurica fungus on onion. (Lev.) G. Arnaud. This pathogen has -Kent Evans, Extension the ability to cause disease on over Plant Pathologist 1,000 different plant species including onions, eggplant, tomatoes, potatoes, peppers, and cucumbers. The patho- gen was first noted in the U.S. in Florida in the mid 1970s, then later in California. It was observed in Wash- ington in 1996 and over the years has appeared infrequently according to a publication by Dr. Lindsey du Toit in the online Plant Health Progress jour- nal (http://www.plantmanagementnet- work.org/pub/php/brief/2004/onion/). Figure 2 (above right). The du Toit’s report describes the disease fungus that causes powdery on onions in a variety trial planted in mildew (Leveillula taurica) Washington; however, the pathogen forms prolific spores on plant was also detected in Idaho at about tissue. the same time. Figure 3 (right). The Powdery mildew has been reported primary spores (conidia) are on onions in Israel, southeastern lanceolate. Europe, and California. In Utah, Extension Vegetable Specialist Dr. Dan Figure 4 (far right). Sec- Drost identified the disease on onion ondary spores are more grown in a Box Elder County variety cylindrical and rounded. trial in September 2007. www.utahpests.usu.edu Utah Pests News - Spring 2008 - page PLANT pathologY NEWS AND information, cont. Watch for “Moldy” Turf This Spring With all our snow this year, get ready for snow mold to appear in residential lawns and turf areas of parks, businesses, and golf courses. Snow molds are fungi that are psychrophilic, or cold-loving, and will attack plants under a layer of snow. Two of the most common snow molds are pink snow mold, caused by the fungus Micro- dochium nivale, and gray snow mold, caused by Typhula incarnata and T. ishikariensis. Both pink and gray snow molds can occur together and almost all turfgrass spe- cies are susceptible to both diseases. Pink snow mold will survive unfavorable conditions in infected plants and debris of previously infected leaves. The fungus will grow slowly at first, allowing infected Wisconsin-Madison of University turf to go undetected for a long period of time. Once conditions are favorably wet and overcast with cool Gray snow mold (above) temperatures, the fungus will spread very rapidly. Sunny typically appears as tan to and dry conditions cause the pathogen to become inac- brown patches on turf, with tive.