Plant Pathology Websites

Do you have a plant problem?
There are a couple of online resources that may help you.

The first thing I would try is from the University of Arizona. Give it a try next time you have a problem.
http://ag.arizona.edu/PLP/plpext/diseases/disease.htm


Cornell University (New York) has a plant pathology department with some good online resources also.  While some of the information won't apply to Arizona gardeners it is an interesting resource.
You can find the website at
http://vegetablemdonline.ppath.cornell.edu/

Basil Fungal Disease

Fear struck my heart when I first read the article on downy mildew on basil.  Basil was a cast-iron plant, trouble free.  It just spent the summer producing more and more wonderful leaves.  But downy mildew has struck, afflicting basil plants first in Florida and then spreading up the east coast to Canada, then the Midwest and California.  The mildew was first found in Uganda in the 1930's and then disappeared only to show up in Europe in 2007 and from there it arrived in America.

The first signs are faint yellow bands on the upper surfaces of the leaves.  The bottom of the leaf becomes dotted with tiny gray specks.  The mildew isn't harmful to humans but it looks unattractive.  You can remove the infected leaves and make sure the plants has good air circulation.  Fungicides don't seem to be very effective.  Some varieties of basil seem to be more susceptable than others.  Lemon and purple basil's seem to resist it better than sweet and Thai basil.

For more information and pictures:
http://vegetablemdonline.ppath.cornell.edu/newsarticles/basildowny.html
http://www.npr.org/templates/story/story.php?storyId=128061773

Let me know if you see this in your garden.

2010 Yavapai Master Gardener Garden Tour

 The 2010 Master Gardener Garden Tour participants enjoyed a warm, sunny day, highlighted by the many bright colors found in the gardens visited. Thank you to all who made the day a success. A special thank you goes to the garden owners who worked over several months to prepare for the tour: Sally Berkshire, Jan Billiam, Bob Burke, Linda Scheerer and Jeannette Teets.  Recognition also is extended to the volunteers who assisted at the gardens, Merle Herrick, Linda Kimberly, Nancy Oliker, Perla Stice, Joan Tyler, Donna Hunter, Susi Wright, Janice Latrell, Lois Rosenow, Gwynne Reese, Dave Black, Trudy Black, Karen Morris, Judy Cowan, Karen Wagley, Patrick Wilcox, Jennifer Young, Barb Waldie, Cindy Schofield, Toni Coon, Grace Baker and Karen Willey. Pete Heisinger’s maps were excellent. We are looking forward to the video to be prepared by John Emerson.

Appreciation also is extended to all who attended the garden tour. Thank you from the Garden Tour Committee: Juliette Colangelo, Toni Coon, Carol Ekeland, Beverly Emerson, Lisa Gerber, Merle Herrick, Betty Loos, Janet Mansoldo and Ron Zmyslinski.

 To see more photos check out the link below:

http://www.flickr.com/photos/41015324@N08/

Summer Pests

The pests of summer are coming if not here already.  Keep on eye out for grasshoppers, codling moths and IPS and bark beetles.

Grasshoppers can be voracious eaters of just about everything.  There are chemical controls but they need to be applied correctly for your safety and the best result.  An easier solution may be to just cover your plants temporarily with a physical barrier.  Lightweight spun fabrics (like Remay and others) are very good at protecting your plants from grasshopper damage.  A bait is available (Nosema locustae).  The bait needs to be applied in the spring as it is most effective on the nymphs, juvenile grasshoppers, that hatch in the spring.  The problem with the bait is that it needs to be applied to a large area.  If you live on a small city lot, it won't provide much protection as grasshoppers can move long distances.  For more information: 

http://cals.arizona.edu/yavapai/anr/hort/byg/archive/grasshoppercontrol.html

Codling Moths are fruit tree pests.  Adults lay their eggs on developing fruit blossoms.  The larvae hatch in 8 to 15 days, tunnel into the fruit and then tunnel out leaving behind their brown excrement.  Once they leave the fruit the fully-grown larva hides in the bark or litter on the ground and another cycle begins.  In Arizona there can be as many as three generations per year.  You can find them by looking at the fruit.  It will have small holes in it or the fruit will drop when it is still immature.  You can help control them by removing and destroying infected fruit and cleaning up debris around the tree.  There are chemical controls but they are not recommended for home growers because they kill bees and require multiple applications.  If you only have a few trees there are alternatives including pheromone traps and sticky bands.  Check the following link for more information:

ag.arizona.edu/yavapai/publications/yavcobulletins/Codling%20Moth.pdf

The damage from IPS Beetles and bark beetles is seen throughout the state.  Vast areas of trees are dead and dying.  The forests around Prescott are particularly hard hit.  There are several different species that infect different trees.  In pine forests you will find IPS Beetles and in cypress trees the Cypress Bark Beetle is the killers.  Infestations are becoming more common as the drought in Arizona has severely stressed the trees.  In pines, the needles start to yellow at the top.  Once you see the needles start to die, the tree is doomed.  On cypresses the branch tips start dying.  A cypress can survive the infestation unless it is stressed usually by drought.  If a cypress in your yard has been infected, you might improve its chances by watering.  The beetles can build up in piles of firewood and slash.  Piles of wood should be removed or covered with plastic and heated up but the plastic has to be completely sealed otherwise the beetles can escape.  There are no chemical treatments that do an effective job of controlling bark beetles.  For more information go to the Yavapai County Cooperative Extension Backyard Gardener columns, type in bark beetle for a series of articles.

http://ag.arizona.edu/yavapai/anr/hort/byg/index.html