Garden Woes – Harlequin Bugs, Squash Vine Borers, Squash Bugs and Potato Bugs

One journey into the garden this week I found a harlequin bug on a broccoli plant, squash bug borer moth flying around the stems of zucchini and a potato beetle on a potato leaf. Sometimes I feel like a crime fighter, because I immediately went into battle mode.

Calabrese and Acadia broccoli
Harlequin bug enlarged..normally about 1/2 inch long

Last year I found that a solution of kaolin clay helps combat harlequin bugs on my broccoli, brussel sprouts, cabbage and other brassicas.  I use the Surround brand of kaolin clay which is a fine powder.

Kaolin Clay Solution

Add the following ingredients after filling a 5 gallon bucket with about one gallon of water

  • 4 cups kaolin clay powder
  • 1 tablespoon castile soap solution ( I use Dr Bronners unscented)
  • Carefully stir in the powder so it is thoroughly moistened , add liquid soap .
  • Add additional 1 gallon water.

Spray on plants early morning or evening when air is still but avoiding the broccoli buds (difficult to wash off broccoli but easier on smoother veggies) . Reapply after rain.

Zucchini with other cucurbits in the background

There are studies that a  kaolin clay solution also works on the zucchini, cucumbers, cantaloupes, melon and squash stems negating the effect of the squash vine borer (SVB). However I’m not sure I am sold on that concept as I did this and  the next day several ants were in  the zucchini and squash flowers. I’ve read some gardeners have noticed an increase in aphids on cucurbits after application and aphids have a symbiotic relationship with ants. Not sure if that was a cause or because we had an intensive rain storm. I need to make more observations before I’m sure about this.

Squash bug eggs on a zucchini leaf

Additionally  check the underside of the leaves for egg clusters from the squash bug every day. Either rub them off  or use packing tape to pick off the eggs and deposit those eggs in a container of soapy water when you’re done.

One other thing organically in my arsenal is neem oil , cold pressed one hundred percent virgin neem oil not the extract. The solution I generally use is:

Neem Oil Solution

  •  1 Tablespoon  neem oil (cold pressed, 100% virgin, not an extract)
  • 1/2 teaspoon castile soap
  • 1 gallon water

Neem oil applied on the asparagus beetle larvae and beetles  works very well. With an infestation on I apply about every 3 days or reapply after rain. Used on cucurbits it seems to cut down on infestations and deters powdery mildew somewhat. With cooler temperatures in the forecast for next week I’m a little concerned about those plants becoming more susceptible to disease.

Potatoes in  root pouches

On potato bugs, I seldom use neem oil but if I do I avoid the flowers. Actually  I have more confidence with the predator bugs eating the eggs before they hatch, so hand picking is another option.

Becoming a detective in the garden is essential since it’s necessary to recognize the bad bugs as well as the good bugs. Paying attention to vegetable plant symptoms or distress signals are necessary crime fighting tools. Until next time.



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