A Zucchini Dilemma

What Is A Zucchini’s Favourite Sport?… Squash!

 I woke up this morning and looked out my window and thought it was strange that it looked like it was going to rain.  I watch several weather outlets and I was sure that no rain was expected, although it would be greatly appreciated.  It was smoke and it was abundant and a weather  smoke alert was being issued.  It is expected to be around for a couple of days and should be looked at as a health hazard as if we did not have enough of them. 

A wonderful gentleman came to my booth at the Lumby Market with an interesting problem that is affecting his Zucchini.  The leaves are being affected by what I believe to be a fungal or mold problem by the symptoms that he described and a plant close to the Market that he pointed out.  Upon some research I am sure it is one of the most common of the fungal diseases that can affect Zucchini and its called Powdery Mildew.  Other fungal problems that can affect Zucchini are Fusarium which will cause the whole plant to wilt then die, Downy Mildew that will cause the plant’s leaves to develop yellow spots and Gummy Stem Blight which will produce black spot on the stems.  Then there are many viral disease problems caused by insects but these I don’t believe to be the problem.  Powdery Mildew is caused by moisture on the leaves which does not have the opportunity to dry off during the day, exposure to the mildew and the perfect weather conditions.   You would think that it would be more of an issue during the spring rainy season but it actually occurs most often when the weather becomes hot which fortunately, was later in the season for us.   It only takes 3 to 5 days from the initial infection to the appearance of the symptoms which begins  with small reddish brown spots and which quickly will turn to a leaf covering of white powdery mold.  It spreads fast and can cover a sizeable area if the conditions allow, such as dry heat and wind.  It will not only affect Zucchini and other squashes it will also infect cucumber, egg plant, lettuce, melons, peas, radish and tomato plants.  Not much can be done once the plant is infected.  Remove any leaves that show symptoms and do not compost them as it can over winter.  The best way to prevent the problem is ensuring you plant in a sunny area with well drained soil with plenty of good clean compost.  Crop rotation is important as is ensuring good spacing and the removal of weeds to ensure good airflow.  Plant disease resistant varieties and try to keep water off the leaves when watering and water early in the day giving the plant the optimal amount of time to dry off.  You can also do a proactive treatment of spray with sulphur  or copper fungicide or neam oil and repeat if needed throughout the gardening season.

Happy Gardening!

Samantha Nason
BS Ranch & Greenhouses
250 547 6567 • samanthanason@hotmail.com

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