Three-Lined Potato Beetle

Our site just went down for the month, and though we have 130 letters outstanding, we decided to photograph this event taking place on our Datura plant. We noticed that the leaves were being eaten and found large numbers of beetle grub, chewing hungrily. They had an unusual viscous liquid on their backs. We also noticed a small green and black striped beetle on the plant. Guessing they were different stages of the same species, we researched the Three-Lined Potato Beetle, Lema trilineata, also called the Old-Fashioned Potato Beetle. This beetle obviously went out of fashion when the Colorado Potato Beetle became such a pest. Our Audubon Society Guide states: “Voracious larvae gather in clusters on potato leaves, nibbling lacy holes and eventually consuming all but the midvein. Unlike other larvae of other potato-feeders, they are blanketed in a wet froth of their own secretions. Adults can be distinguished from the Striped Cucumber Beetle by the constriction behind the thorax.”Datura is a member of the potato family, which explains the beetles presence on this hallucinogenic plant.

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