In most cases, the insecticide malathion is harmless to plants because it acts by working on the central nervous system, which plants don't have. However, some plants, such as jade (Crassula ovata), which grows outdoors in U.S. Department of Agriculture plant hardiness zones 10 and 11 and as houseplants elsewhere, are sensitive to malathion. If you make the mistake of spraying your jade plant with malathion, all is not lost. A few actions can free your plant of the insecticide and allow it to recover in time.
Wear gloves and a long-sleeved shirt to keep the malathion from getting on your skin. Take the container with the jade plant outside.
Cover the soil around the jade plant with a piece of plastic to protect it from water spray.
Hold the base of the plant and the plastic in place as you tip the pot so it is at about a 45-degree angle. You may need someone to help you hold the pot while you spray the plant leaves.
Spray the jade leaves and stems with water, directing the spray away from the plant and pot. Spray until the odor of the malathion -- described as similar to garlic or skunk scent -- dissipates .
Repot the jade plant if you sprayed the soil or washed the malathion into the soil when you rinsed the plant.
Prune dead branches, cutting where the branch joins another branch or stem. Use sharp, clean pruning shears and make the cut flush with the stem.
Carefully tip the plant out of the pot, ensuring the branches and leaves aren't crushed or dislodged.
Brush as much of the soil from the plant roots as you can. Dispose of the soil in the pot.
Rinse the remaining soil from the plant roots and from the inside of the pot.
Add fresh potting soil formulated for cacti and succulents. Fill the pot with enough soil so the plant will sit at the same level it sat previously. Set the jade plant in the center of the pot and fill in around the roots with soil.
Water the newly potted plant and fill in with more potting soil if needed as the soil settles. If the potting soil did not have fertilizer already added, give the jade plant 1/2 teaspoon of a general-purpose fertilizer dissolved in 1 gallon of water and watered into the soil.
Watch your jade plant for signs of recovery and hope for the best.