Facing down any infestation can rapidly strip the comfortable feeling from your home. And if that infestation is bed bugs, it’s worse: those little vampires will go straight for your safe place, your sanctuary—your bed. To make matters even more dire, the best pesticides we’ve got for driving bed bugs off are rather ineffective. Some bed bugs are naturally resistant to the poisons.
There’s a new tool, though, in the battle against bed bugs. As reported by Inside Science, a team of researchers from Penn State University have shown that a fungus, Beauveria bassiana, when sprayed on your linens, is completely effective at wiping out the bugs. Bed bugs that crawled on a sheet sprayed with the fungus went on to develop a fuzzy white infection. But, before they did so, some bed bugs passed the spores on to their brethren.
As with all insect-pathogenic fungi, Beauveria produces spores that are resistant to environmental extremes and are the infective stage of the fungal life cycle. The spores (called conidia in this case) infect directly through the outside of the insect’s skin. Under favorable temperature and moisture conditions, a conidium (singular of “conidia”) adhering to the host cuticle will germinate. The fungal hypha growing from the spore secretes enzymes which attack and dissolve the cuticle, allowing it to penetrate the skin and grow into the insect body. Once inside the insect it produces a toxin called Beauvericin that weakens the host’s immune system. After the insect dies, an antibiotic (oosporein) is produced that enables the fungus to outcompete intestinal bacteria. Eventually the entire body cavity is filled with fungal mass. When conditions are favorable the fungus will grow through the softer parts of the insect’s body, producing the characteristic “white bloom” appearance.
Back in the early modern era, says Mahr, Beauveria bassiana was the bane of silkworm farmers. But now, the spores may be the boon of city dwellers everywhere, whose buildings are plagued with bed bugs. The treatment is going through review by the Environmental Protection Agency right now.
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