RESUMEN
Cilembu sweet potato is one of Indonesia's leading agricultural commodities. The high carbohydrate content in sweet potatoes has the potential to change into sugar (glucose, sucrose, and fructose) during storage. The level of sweetness is one of the characteristics that determines the quality of sweet potatoes. The sweetness level of sweet potatoes is influenced by various factors, including genetics, environment, and their interactions. Apart from that, the role of invertase-producing bacteria in breaking down carbohydrates into sugars is very important. Information regarding the number of invertase-producing bacteria in Cilembu sweet potatoes and their activity during storage is still limited. This research aimed to determine the number and activity of invertase-producing bacteria in Cilembu sweet potatoes and estimate the relationship between activity and total invertase-producing bacteria during storage of Cilembu sweet potatoes. The results showed significant differences between the number and activity of invertase-producing bacteria at each storage time. There is a relationship between sugar levels and invertase-producing bacteria. Sucrose levels had a negative and significant correlation with fructose levels (-0.56) and invertase-producing bacteria (-0.58). Glucose levels were significantly and positively correlated with fructose levels (0.91) and invertase-producing bacteria (0.88). Fructose levels also significantly and positively correlated with invertase-producing bacteria (0.95). This information can be used as a reference in determining the quality of sweet potatoes directly and indirectly.
RESUMEN
Brown rot fungus Fibroporia radiculosa (Peck) Parmasto grown in decayed wood and non-wood material, potato dextrose agar (PDA) media, deterred Reticulitermes speratus (Kolbe) feeding. Decayed wood and PDA media were extracted and tests were performed to assess termite feeding behavior towards the extracts. We found that the extract from PDA media also suppressed termite feeding, although it did not induce mortality. Using gas chromatography and mass spectrometry analysis, two bioactive compounds were detected from the decayed wood extract, and one was detected from the PDA extract. Based on National Institute of Science and Technology (USA) Mass Spectral library match and compound fragmentation, both of the compounds belong to the sesquiterpenes family.
RESUMEN
No-choice feeding tests using ethanol, chloroform, and acetone extractives of teak (Tectona grandis) heartwood clearly showed feeding deterrent activity and toxicity to the subterranean termite Reticulitermes speratus. The amount of 2-methylanthraquinone (MAQ) in teak wood extractives was not related to the feeding deterrents or toxicity, as shown by the no-choice feeding tests conducted using crude extractives containing various amounts of MAQ, MAQ alone, and fractions of crude extractives. As a native pest, the subterranean termite Coptotermes formosanus was more tolerant to the fractions of crude extractives than Reticulitermes speratus, and the mortality observed in C. formosanus was not due to the presence of MAQ.
RESUMEN
We found that decayed wood stakes with no termite damage collected from a termite-infested field exhibited a deterrent effect against the termite Reticulitermes speratus, Kolbe, 1885. The effect was observed to be lost or reduced by drying. After identification, it was found that the decayed stakes were infected by brown rot fungus Fibroporia radiculosa (Peck) Parmasto, 1968. In a no-choice feeding test, wood blocks decayed by this fungus under laboratory condition deterred R. speratus feeding and n-hexane extract from the decayed stake and blocks induced termite mortality. These data provided an insight into the interaction between wood-rot fungi and wood-feeding termites.
