Lafayette Parish Master Gardeners

GERALD'S CORNER

By Gerald Roberts
Horticulturist/Master Gardener Program Coordinator
LSU AgCenter

  • Home
  • About Us
  • Programs and Activities
    • School Garden Initiative
    • Vermilionville Medicinal Demonstration Garden
  • Festival des Fleurs 2023
  • Resources
    • Louisiana Certified Plant Habitat
    • LSU AgCenter
    • Speakers Bureau
  • Become Master Gardener
  • Member benefits
  • Contact Us
  • Sign up for emails
  • Member login

February 2016

2/1/2016

0 Comments

 
Picture
Hello Master Gardeners,

Recently I’ve been receiving calls and pictures regarding camellia flowers being discolored after opening or some being discolored and only partially opening. On white camellia flowers the flower petals take on a tan to brown color and many fall to the ground. After discussions with Dr. Raj Singh, LSU AgCenter Plant Pathologist , and Director of the Plant Pathology Lab at LSU, we concluded that the majority of the problems were caused by cold injury. However another problem that mimics cold injury is Camellia Flower Blight which is caused by Sclerotinia camelliae which becomes active during cool moist conditions.These conditions are what Dr. Singh refers to as favorable conditions for camellia flower blight. To those of you who had the fortune of sitting through Dr. Singh’s plant pathology class as you received classroom instructions to become a certified Master Gardener, you should have recalled that he said in order for infection to take place there are three things that need to be present: favorable conditions , a host, and a pathogen. When camellias are blooming in cool temperatures with abundant moisture, camellia flower blight is highly probable. Camellias growing in shade where moisture is more abundant are more susceptible. The fact that camellia flower blight mimics cold injury may be confusing to home gardeners because of the similar appearance, but remember, if the petals have a slippery, slimy texture then it’s camellia flower blight. If the discolored petals have a dry leathering feel then in all likelihood it is cold injury. If it is camellia flower blight all infected flowers that fall to the ground should be picked up and discarded. Some gardeners even picked the infected flowers off the plant and discarded them. If this is not done, the pathogen will over winter in the old infected flowers and be there to infect the next crop of camellia flowers.

Picture
Picture
I’m also receiving numerous calls from home gardeners regarding a high number of broccoli plants that are bolting or as old gardeners say, going to flower and seed. We see this occurring when these plants are repeatedly exposed to warm temperatures, which is common with late season broccoli. If you recall we’ve had several periods of above normal temperatures and since I’m getting calls from all across Lafayette and surrounding parishes it’s safe to conclude that the warm weather patterns are to blame. Bolting is actually a survival mechanism in certain plants , where by if the temperature ranges are higher than what the plant has been genetically programmed to handle, the plant feels threatened and tries to produce the next generation by flowering, followed by seed production. Some research indicates that to some degree as a gardener these plants can be mulched or watered to keep the roots cool which may minimize bolting. However, I’m not sure if that has been proven! All cruciferous vegetables such as broccoli, cauliflower, Brussels sprouts, turnips , kale, cabbage and several others, are susceptible to bolting!!

Picture
One of the most serious diseases of cruciferous crops worldwide is Black Rot caused by the bacterium Xanthomonas campestris. If the pathogen is present in seeds or transplants, and favorable conditions develop such as wind and rain producing splashing water, it is highly likely that infection will take place. Many gardeners have called and sent pictures of browning of the leaves of broccoli, cabbage, and cauliflower within the last month. They should remember the rainy weather pattern we’ve been having and continuing to have. The infection usually begins on the leaf margins where the pathogen enters the plant through natural openings in the leaf or through insect wounds. The leaves begin to take on a tan to brown V shaped lesion in its early stages and progressively moves downward from the leave margin to consume an increasingly larger area of the leaves of these vegetables. This causes plants to sometimes die prematurely, remain small, or lowers the quality of the vegetables produced. Symptoms are sometimes confused with nutritional problems. In the very early stages of development, infected leaves can be removed and applications of copper fungicide can be made to slow the spread of Black Rot.

Picture
Gerald P. Roberts
Horticulturist/Master Gardener Program Coordinator
LSU AgCenterhere to edit.
0 Comments

Your comment will be posted after it is approved.


Leave a Reply.

    Gerald Roberts

    Horticulturist/Master Gardener Program Coordinator
    LSU AgCenter
    1010 Lafayette St., Suite 325
    Lafayette, LA 70501
    GRoberts@agcenter.lsu.edu
    Office (337) 291-7090
    Fax (337) 291-7099

    Archives

    April 2016
    March 2016
    February 2016
    January 2016
    December 2015
    November 2015
    August 2015
    July 2015
    June 2015
    May 2015
    April 2015
    February 2015
    January 2015
    December 2014
    November 2014
    October 2014
    September 2014
    August 2014
    June 2014
    May 2014
    April 2014
    March 2014
    February 2014
    January 2014
    December 2013
    November 2013
    October 2013
    September 2013
    August 2013
    June 2013

    Categories

    All
    2013
    2014

    RSS Feed

     Members only    © 2013-2023 Lafayette Parish Master Gardeners Association, Inc. All Rights Reserved