The leaf stalks of the rhubarb are used as a dessert or as an ingredient in sweet dishes. That’s the part you’re taking advantage of here. Rhubarb taste is similar to that of green apple and sometimes more sugar is added to it to make them even sweeter. A. Leaves of the Rhubarb Plant. The use of a natural pesticide made from rhubarb leaves is frequently promoted. Often a small dose of something toxic may have no effect, or make them mildly ill, but a continued intake of toxins will definitely screw up their systems. Rhubarb Leaf Pesticide. Slugs typically feed at night and hide from the heat of the day by returning to the soil / leaf litter below the plants. Rhubarb’s killer reputation apparently dates to World War I, when rhubarb leaves were recommended on the home front as an alternative food. Q. We’re hoping the insects will get it on them, munch on the leaves a bit, and die. Cold damaged rhubarb leaves will shrivel and turn black. The toxins build up and cause damage to internal organs. Any new growth, which emerges later in spring, should be safe to eat. I think you should definitely keep them away from the rhubarb leaves in the future! Rhubarb is an excellent source of many nutrients such as vitamins, minerals, antioxidants, phytonutrients, and polyphenols, etc. that provides a number of health and beauty benefits. (Cue the sinister laughter.) Scroll down for a recipe to make a homemade natural insecticide using your rhubarb leaves, and a link to many more recipes for natural and organic pesticides and insecticides. I mean, I doubt it would kill you, but you’re not supposed to eat rhubarb leaves because they are poisonous. Damaged rhubarb stalks should be pulled and discarded. Well, rhubarb leaves, which you are not supposed to include in baking or cooking, contain oxalic acid, which causes kidney stones. Boil the leaves in some water for 20 minutes, cool, add a few drops of dish detergent and you have a spray that will kill all kinds of bugs and fungal diseases. They also leave a slime trail as the move across plants. Oxalic acid is a poisonous, colorless substance commonly used in products such as metal polishes, stain removers, bleaches, and anti-rust products. I wouldn’t spray this on vegetables just before harvest. If the damage is on the leaves - and it looks like large, ragged holes in the leaves, and you do not see a likely culprit when you check the rhubarb during the day, it could be slugs. Rhubarb became infamous in the First World War when people ate its leaves as a vegetable - and died from too much oxalic acid. Not you. Damaged stalks become soft and mushy. Rhubarb plants showing no sign of damage are fine and can be harvested. When can I start harvesting my newly planted rhubarb?