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Alert: May 8, 2006 |
Wheat disease Update |
| Are Soybean Seed Treatments Necessary? |
| New Faculty Member Joins Extension Group |
| Spring Anthracnose Diseases |
| Plant Disease Diagnostic Update (April 2006) |
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Wheat Disease Update With regard to foliar diseases, the health of the Kansas wheat crop is currently excellent. The presence of either leaf rust or stripe rust is currently extremely low. Coupled with reports of low rust incidence in Oklahoma and the Texas panhandle, it is unlikely that rust will develop to levels requiring a fungicide application in Kansas in 2006. In fact, much of the wheat in the southern part of the state is already beyond the stage (full heading, Feekes 10.5) at which a fungicide can be applied. There is still some risk of head scab occurring in those parts of the state where wheat has not flowered yet. Keep in mind that results of fungicide usage to control scab have been mixed. Scab infection only occurs when it rains during flowering. To effectively control scab, the fungicides must be in place by full heading as with foliar diseases. This requires application before a grower knows if there is a danger of infection or not. If a grower has fairly consistently had scab problems and wheat is following corn, then a fungicide application might make sense, otherwise it is probably best to due nothing. By far the most serious problems in spring wheat fields have been the viruses, wheat streak mosaic, high plains and barley yellow dwarf. Some fields I visited in southeast Kansas were pretty much 100% infected with barley yellow dwarf virus. We have received lots of reports from western Kansas of high levels of wheat streak mosaic and high plains and this has been correlated to a large number of positive samples received in the diagnostic clinic. Of course there is little that can be done at this point. Disease levels of all three viruses are made worse when susceptible varieties are planted early, volunteer wheat is not managed, and when extended warm falls and early warm springs favor insect feeding. (Jardine)
Are Soybean Seed Treatments Necessary? Long term research at Kansas State has demonstrated that when seed treatments are routinely used on soybeans planted before May 15, yields on average will be increased enough to more than pay for the cost of the treatment. From 2003 - 2006 in Kansas trials, treated seed out yielded untreated seed by over 2.5 bushels per acre. The best seed treatment products will contain a combination of materials for the best broad spectrum control. The product should contain either metalaxyl or mefanoxam for Pythium and Phytophthora control in combination with fludioxonil, azoxystrobin, carboxin or difenconazole. For growers planting no-till, data suggests that use of a seed treatment through Memorial Day is cost effective. (Jardine)
New Faculty Member Joins Extension Group Greetings, everyone. I would like to introduce myself. My name is Dr. Megan Kennelly, and I am a new faculty member in the Department of Plant Pathology, in the position formerly held by Dr. Ned Tisserat. My responsibilities include extension and research for horticultural crops (turf, ornamentals, fruit, vegetables, shade trees, etc). I also work extensively in the diagnostic lab. I grew up in Madison, Wisconsin, and for my undergraduate degree I attended the University of Wisconsin-Madison. I majored in botany, but I took several courses in plant pathology. During the summers I worked in the plant pathology department assisting in research on fungal diseases of cranberries, an important fruit crop for Wisconsin. After graduating from the UW, I attended Cornell University for my PhD. I did some field research on a disease of grapevines called downy mildew, caused by Plasmopara viticola. Downy mildew is considered the second most important disease of grapes worldwide, after powdery mildew. When I finished at Cornell I moved to Michigan State University to work as a researcher for about 9 months. At MSU I studied a bacterial disease of apples and pears called fire blight. It can be a devastating disease for commercial apple and pear growers in wet climates. Fire blight occurs in Kansas during wet springs. I started at K-State at the end of February 2006. In my first 3 months I have been busy meeting people and planning future research and extension projects. I=m very excited to be here in Kansas, and I=m looking forward to getting to know the horticultural industries, the county agents, and others with interests in horticultural crops. (Kennelly)
Spring Anthracnose Diseases Every spring in Kansas, sycamore trees leaf out and then start to shed. We often see a similar occurrence on ash, maple, oak and elm trees. Under cool, wet conditions a group of fungi cause a disease called anthracnose. It can cause leaf spots, shedding, twig cankers and shoot blighting. The leaf spots are dark, irregular and sometimes follow the veins. When the weather is particularly rainy, defoliation can be extensive and the damage can appear to be quite dramatic. Homeowners unfamiliar with anthracnose are often concerned that the tree is going to die. The good news is that recovery is around the corner. When summer arrives, the weather warms up and dries out and the disease ceases to be active. Trees re-leaf and look great for the remainder of the summer. Other than summer watering to speed recovery, control measures are not necessary. (O=Mara)
Plant Disease Diagnostic Update (April 2006) Garden & Landscape observations:
African violet:
Powdery mildew. Crop observations:
Alfalfa:
Cold temperature damage to the plant tops; alfalfa mosaic virus; alfalfa
weevil.
Soybean
rust has been reported in FL/AL/GA as well as TX (destroyed) and
Mexico.
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Sincerely,
Judith O’Mara |
Cooperative Extension Service Tel: 785/532-5810 http://www.oznet.ksu.edu/plantpath |
KSU, County Extension Councils and U.S. Department of Agriculture Cooperating All educational programs and materials available without discrimination on the basis of race, color, religion, national origin, sex, age or disability. |
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Web updated 9/01/06 |