Saturday, July 10, 2010

Something's Afoot in the Garden, Aphids & Disease

Bushwick Rooftop Container Garden Vegetable Pest

So I was all set to write about how well all the vegetable plants are doing in the rooftop containers and then we had that ridiculous heatwave.  When the temperature rises above 90 I don't step out on the rooftop until after sunset, so it has been about a week since I've seen the garden in daylight.  I was hoping everything would be the same, but unfortunately that wasn't the case.  My cucumber plant now has spider mites.  Spider mites are super tiny pests that suck the life out of plant leaves.
Injury is caused as they feed, bruising the cells with their small, whiplike mouthparts and ingesting the sap. Damaged areas typically appear marked with many small, light flecks, giving the plant a somewhat speckled appearance. Following severe infestations, leaves become discolored, producing an unthrifty gray or bronze look to the plant. Leaves and needles may ultimately become scorched and drop prematurely.
Dry conditions greatly favor all spider mites, an important reason why they are so important in the more arid areas of the country. They feed more under dry conditions, as the lower humidity allows them to evaporate excess water they excrete. At the same time, most of their natural enemies require more humid conditions and are stressed by arid conditions. Furthermore, plants stressed by drought can produce changes in their chemistry that make them more nutritious to spider mites.
They thrive in hot, dry weather so it's no surprise that they're in the garden.  Many of the cucumber leaves have white spots, some have already completely dried out and turned from yellow to brown.

Bushwick Rooftop Container Garden Vegetable Pest

Bushwick Rooftop Container Garden Vegetable Pest

Spider mites are very small so they're hard to spot with the naked eye, but you can tell they're present if the underside of the leaves look "dusty."

I hosed the entire plant down with a strong stream of water and will continue to do so periodically through the rest of the growing season. I also added a little more fertilizer to my DIY self-watering container 2, hopefully the plant can grow faster than the mites can kill it.  I assume there's some kind of spray I can buy to treat the mites faster, but I've decided to not be too aggressive about treating the problem.  I've realized, after eating several cucumbers off the vine, that I don't like them enough to grow them, so ultimately I'm not that concerned about the fate of this plant.  If it makes it great, if not oh well.

Bushwick Rooftop Container Garden Vegetable Disease

Something is also going on with the cherry tomato plant.  Many of the leaves toward the center of the plant are yellow with brown spots.  I'm hoping it's just a nutrient deficiency and not some fungus.  I've added more fertilizer to my DIY self watering container in case it's the former and ordered some organic fungicide in case it's the latter.  If it is a fungus I'm leaning toward early blight.  Unlike the cucumber plant, I absolutely love homegrown cherry tomatoes, so I'm going to do all that I can to make sure this vegetable plant survives the season.

Bushwick Rooftop Container Garden Vegetable Disease

Serenade® Garden Disease Control Concentrate, 30 oz.: $24.85

Running Total: $139.36

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2 comments:

  1. My cherry and Brandywine plants also got aflicted with something within the past two weeks. The cherry has dark patches on the stems.

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  2. My cucumber leaves have started to turn a weird yellowy / brown color, and never thought it would be mites! Argh, I'll have to try to water the heck out of them tomorrow.

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