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Pest Problems: Rose Saw Fly

Here are pictures of a pest I have been battling for the last couple years on my knockout roses.  Every summer they have been plagued with this insect, and my attempts at spraying had been unsuccessful.  I think I finally have them figured out and have a few tips for control.

The tiny green worm you see is a rose saw fly.  These larvae are out in early to mid spring and will feed on the leaves of your roses, before going back into the ground to lay new eggs.  They can be organically controlled by spraying with a hard spray of water and knocking them off the plant.  The larvae are a soft-bodied insect and the force of the water will easily kill them.  They can be controlled with horticultural oils and other insecticides as well, however they must be sprayed directly on the insect, which resides on the underside of the leaves, making them hard to spray.  Remember that all insecticides are non-selective, so there is a chance of killing other beneficial insects and natural predators, so use only as a last resort and spray in the early morning to avoid targeting the good insects.

I have been physically removing them and recently applied a neem oil.  I want to see how this does, as it is not toxic to other insects that pass by unless they got sprayed at time of application.  I carefully lifted each plant and sprayed underneath where I saw the saw fly larvae.  *Neem oil does not quickly kill the pest, so do not expect them to die immediately.  It uses hormones to affect their eating and reproductive habits, stunting them and keeping them from feeding and reproducing.  Here is a good link for more information on how it works.    http://www.discoverneem.com/neem-oil-insecticide.html