the pesticide is generally one or more non metabolizable or only slightly metabolizable carbohydrates of relatively low molecular weight resulting from their having fewer than 12 carbon atoms per molecule although there are exceptions which permit larger molecules to be used in the practice of this invention the pests consume the substance because the active ingredient is sweet and attractive or if the active ingredient itself is not sweet a sweetening agent is incorporated into the pesticide the substance which is either not transported poorly transported or not actively diffused across the digestive tract membranes of the pests is generally selected from among low molecular weight carbohydrates with such properties because they remain inside the intestinal tract and are relatively small molecules they create osmotic pressure which can only be equilibrated by the movement of water from the rest of the pest body into the intestinal tract this results in the excretion of large amounts of water and or damage to internal organs with death occurring from dehydration and or structural damage the active substance used in the practice of this invention i e the substance which is either not transported or which is poorly transported across the digestive tract membranes of the pest upon ingestion and which causes an osmotically driven influx of water into the intestines may be a low molecular weight organic compound of low or non metabolizability or a low to moderate molecular weight compound of non or low degradability and non or low transportability across the digestive tract membranes such compounds include all l hexoses except sorbose which occurs naturally.