Absolute Stereochemistry of TXIB, a Bioactive Plasticizer That Inhibits Oviposition of the Peach Fruit Moth, Carposina sasakii (Lepidoptera: Carposinidae).

TXIB (2,2,4-trimethyl-1,3-pentanediol diisobutyrate), a common plasticizer, inhibits the peach fruit moth, Carposina sasakii from ovipositing on young apple fruits. Using an insect assay and gas chromatography with an electroantennographic detector (GC-EAD) analysis, the stereochemistry of the bioactive compound was identified to be 3R, whereas (3S)-TXIB showed no activity. The inactive enantiomer did not inhibit the activity of commercially available TXIB, which was a racemic mixture. When the female moth was placed on the TXIB-treated fruits in the oviposition assay, she repeated grooming antennae. The reason why the moth detects this artificial compound is unknown, although the stereochemical structure of TXIB could have given an abnormality to the moth's antennae.

Triterpenes induced by young apple fruits in response to herbivore attack.

Apples Malus domestica, known as a rich source of triterpene acids, induced more variety and quantity of triterpene acids in response to herbivory or mechanical damage. There were 3 major induced compounds: pomaceic acid and euscaphic acid, both of which are known apple triterpene acids, and 2α,19α-dihydroxy-3-oxours-12-en-28-oic acid (named eriobotoric acid), which was first identified in apples. In this study, the 3 compounds' induction curves after damage, varietal differences in induction amounts, and physiological roles against pest insects were further investigated. Eriobotoric acid showed clear antifeedant activity against lepidopteran insect Spodoptera litura but not against apple pests.

Inhibitory substances contained in calcium carbonate wettable powder on the oviposition of the peach fruit moth, Carposina sasakii.

Spraying a calcium carbonate suspension "White Coat" on the fruit of apples significantly suppresses the oviposition of the peach fruit moth, Carposina sasakii. In gas chromatography (GC) with an electroantennographic detector analysis, adult female antennae showed responses to three compounds that were identified as 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (TXIB) and its two mono-hydrolyzed analogs, texanols (1- and 3-isobutyrates), all added as a plasticizer to the agents. An oviposition-choice test using adult moths revealed that TXIB has clear deterrent properties when applied to young apple fruits. Video recording analysis showed that female moths spent longer on self-grooming and searching around TXIB-treated fruits. In the same assay, pure calcium carbonate treatment prevented the moths from climbing up or landing on the fruits, while such was not the case with White Coat-treated fruits. TXIB, an adjuvant aimed to provide rain/wind resistance, weakened the slipperiness of the calcium carbonate coating but, coincidentally, maintained the oviposition inhibitory activity of the White Coat by its deterrent odorant.