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Bugs & Blights

April, 2009

Welcome to the "Bugs & Blights News"!

Bugs and Blights Newsletter is based on a column I wrote for WSNLA B&B for many years. It is evolving to a web based newsletter to update you on insect, disease and abiotic problems so that you can solve your own plant problems or diagnose and help your customers. I will provide links to additional resources and photos.

WSU NURSERY and GARDEN CENTER WEBSITE
http://gardencenternursery.wsu.edu/
Charles Brun has developed and is working on a website for the nursery/greenhouse industry. In Snohomish, I'll be focusing on local nursery issues, links and Pest/Problem Management as well as issues facing the nursery industry.

WSU SNOHOMISH COUNTY WEBSITE
We are working on a complete revision of our website to include
1) Commercial growers and retailers (greenhouse, field and container growers, turf, garden centers, retailers)
2) Landscape service professionals (from design to maintenance)
3) Pest management professionals, IPM and Pest info and Bugs and Blights
4) Home and Garden (pests of structures, stored products, gardens, landscapes and turf and sources of services)
5) Master Gardeners password-protected pages

In addition, all our programs from 4-H, to forestry and nutrition are revamping their pages.

Sites will have links to relevant resources within and outside WSU, agencies, professional associations, plant societies and organizations. If it's been done and is good, we'll link you to a site. If there's a gap, we'll work to fill it. It will be another month before things are up and running. I look forward to your comments, suggestions and links of value that you recommend. (Note that we will be linking to informational sites...these pages will not be for advertising)


BUGS AND BLIGHTS NOTICE

Tent Caterpillars begin to hatch when apples blossom.

Watch for small tents with young black, later orangish, caterpillars. At the small stage, tents can be pruned or squashed on cold days when caterpillars are inside the tent. Bt works well for young caterpillars. The larvae must eat it so apply it AFTER a cold spell when larvae are finally able to leave the tent and will be eating to make up for those days of confinement in the tent.
Bt is less effective when larvae are large and not eating as much; or when they have begun to disperse in early to mid June. The hosts are numerous, including rosaceous plants, alder, birch, cotoneaster, cherry apple and poplar. All hosts are broadleaf plants.
Hortsense controls for homeowners: http://pep.wsu.edu/hortsense/

Apple Ermine Moth
is restricted to apple and a few related species. The caterpillars are naked and spotted and make several small tents. They feed within the tent which may be hidden by a few leaves tied together. See http://cru84.cahe.wsu.edu/cgi-bin/pubs/EB1526.html (you can print this out for free or buy a copy or read on-line).

Cherry Brown Rot Blossom Blight and Fruit Rot

If it's spring, it must be brown rot. Right now you can expect the first of the brown rot problems to come in on a number of Rosaceous plants (see hosts below).

• The fungus spores land on newly opened blossom buds or petals and invade the soft tissue.
  
• Blossoms droop but remain on the tree rather than shedding their petals in a lovely carpet below the plant
  
• In moist weather look for a brownish fuzz (fungus fruiting bodies) on the blossoms (signs)
  
• It kills/consumes the blossom tissue and moves down the blossom petiole to the twig or flower spur
  
• It moves further along the twig 'till it hits a small branch.
  
• If the plant can't stop it there, it will move down to the next branch.
  
• Everything after the girdled tissue dies, so you may find only one affected blossom but everything beyond it collapses.
  
• Eventually the plant stops the fungus growth and at that point a canker usually forms.
  
• The plant tries to seal off the injured area by forming callus tissue around the affected area
  
• These cankers can be distinguished from others by the small branch stub or flower stub in the middle of the canker.
  
• Blasted blossoms are a likely cause for poor fruit production in many cherries, prunes, plums, peaches.
  
• Occasionally there will be additional flagging as a few leaves droop in mid summer and turn orange-brown.
  
• Late in the season fruit may turn fuzzy and shrivel, due to late infection on developing fruit
  

Hosts

• Stone fruits: cherry, peach, plum, prune
  
• Ornamentals: Flowering quince, flowering almond
  
• Occasionally: Apple, and if an infected blossom lands on a cotoneaster, or other rosaceous host, it may be able to invade a stem or leaves.

  The only control for brown rot of ornamental stone fruits is protecting the buds and blossoms with fungicide in the spring. (Too late now, unless it is a late-blooming fruit). Put this disease on the calendar for the next spring and watch for bud break. (We are working toward better ways to alert folks when conditions are ripe for managing pests). For edible fruit, check the current PNW Handbook http://plant-disease.ippc.orst.edu/disease.cfm?RecordID=272 (be aware that many of the fungicides listed are not listed for home use)
  For homeowners: http://pep.wsu.edu/hortsense/ select Tree Fruits, then Brown Rot or search for Brown Rot
  
  CROP INSURANCE FOR NURSERY GROWERS
  
  Growers, if you are interested in this insurance for commercial plant producers, send me an email and I'll forward the details.
  
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  Chirps!
  Sharon J. Collman
  Extension Educator, Horticulture and IPM
  600 128th St. SE
  Everett, WA 98208
  425-357-6025
  425-338-3994 fax
  collmans@wsu.edu