A team of researchers from Universitat Politècnica de València, in where else but Valencia, Spain, the University of Navarra in Pamplona (Fun Fact: The founder of the University of Navarra is also the founder of Opus Dei the “ultra-secret” Catholic organization featured in the bestselling thriller The Da Vinci Code), and a Belgian company Biobest Belgium NV have studied thrips: a disease that affects Valencia oranges and is transmitted by a tiny, winged pest and they may have found a bug to fight the bug.  

The guilty bug is called Kelly’s citrus thirps or Pezothrips kellyanus and whatever you do don’t do a Google image search for the insect- here is a link. You’re welcome.

"This bug causes a round scar on the top of fruit. This is a purely aesthetic condition, but with serious consequences. For example, half of the Valencian production is exported and a fruit affected by this pest can not be exported, with the economic losses it entails," said Valencia professor Ferran García.

If the affects of this disease are “purely aesthetic” I’m not sure it needs to be controlled at all. This seems like simply a matter of telling consumers that the gray scummy looking scar on the top of the fruit, while unsightly, doesn’t indicate that the orange is rotten. But since grocery stores don’t like to buy damaged fruit because customers think it’s bad a pristine rind that will eventually be thrown out is important not just for the Valencia orange but all produce so researchers will continue to look for ways to efficiently manage pests.

Four citrus orchards in Valencia were studied by Politècnica de València and they identified fifteen species of eight families of mites and two were prevalent: Parasitus americanus (Parasitidae) and Gaeolaelaps aculeifer (Hypoaspis aculeifer). These are soil mites and not the bugs responsible for thrips, but after testing and soil samples scientists think Gaeolaelaps aculeifer could be used to combat thrips.

"The study concluded that there is a direct relationship between a high presence of this mite in the earth and a low presence of thrips on the fruit. This suggests that these mites could be an alternative to the chemical products currently used," said García.

The thrip fighting Gaeolaelaps aculeifer mites like it dirty too and piling manure on the soil does not affect their populations. Researcher Cristina Navarro said the fertilized soils has an increased number of mites. Turns out you can attract more pests with manure.