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Maize pre-cultivation was hypothesised to alleviate soil deterioration in replanted apple orchard, and this would be expected to be reflected in the nematode community in the soil. To test this hypothesis, soil parameters and nematode population composition were measured. Compared with replanted apple treatment, soil pH, soil organic matter, ammonium nitrogen and the available P and K content of the soil were enhanced after maize pre-planting cultivation. Maize pre-cultivation increased bacterivorous nematode populations and decreased herbivorous nematode populations, mainly Pratylenchus, Paratylenchus and Tylenchus spp. The Shannon-Weaver diversity index (H′) and the richness (SR) of the nematode population, the Wasilewska functional index (WI) (soil health index) and the maturity index (MI) were increased at the flowering stage after 2-year maize pre-planting treatment, and WI was increased at the maturity stage compared with replanted apple treatment. These results indicate that maize pre-cultivation can alleviate soil acidification and deterioration of the physicochemical properties of soil and improve soil health, food web stability and soil ecosystem sustainability in replanted apple orchard. These changes are accompanied by changes in the soil nematode communities. [ABSTRACT FROM AUTHOR]

The essential oil from the root tubers ofLindera aggregatawas analyzed by GC-FID and GC-MS. Thirty-five compounds were identified and the main components of the essential oil were α-longifolene (15.13%), bornyl acetate (11.49%) followed by α-eudesmol (9.14%), α-pinene (7.88%), β-phellandrene (6.31%), β-terpinene (5.67%) and α-terpeninol (5.11%). During the screening program for new agrochemicals from Chinese medicinal herbs and wild plants, essential oil ofL. aggregatawas found to possess insecticidal activity against two grain storage insects,Sitophilus zeamaisandTribolium castaneum. The essential oil ofL. aggregatapossessed contact toxicity againstS. zeamaisandT. castaneumadults with LC50values of 61.65 and 18.47 μg/adult, respectively. The oil also showed pronounced fumigant toxicity againstS. zeamaisandT. castaneum(LC50= 23.04 and 14.69 mg/L air, respectively). [ABSTRACT FROM PUBLISHER]

During our screening program for new agrochemicals from the local wild plants and Chinese medicinal herbs, the essential oil ofCyperus rotundusrhizomes was found to possess strong insecticidal activities against the booklice,Liposcelis bostrychophilaBadonnel. Essential oil ofC. rotundusrhizomes was obtained by hydrodistillation and analyzed by Gas chromatography-Mass spectrometry. A total of 35 components of the essential oil ofC. rotunduswere identified. The main components of the essential oil were α-cyperone (29.38%), cyperene (13.97%), caryophyllene oxide (6.71%) and β-selinene (6.47%). Bioactivities-directed chromatographic separation on repeated silica gel columns led to the isolation of two compounds: cyperene and α-cyperone. α-Cyperone exhibited pronounced contact toxicity againstL. bostrychophila(LC50= 41.32 μg/cm2) and was more toxic than cyperene (LC50= 50.08 μg/cm2) while the essential oil acting against the booklice showed an LC50value of 102.11 μg/cm2. These results suggest that the essential oil ofC. rotundusrhizome and the two isolated constituent compounds may be used in grain storage to combat insect pests. [ABSTRACT FROM PUBLISHER]

The effects of a new species Heterorhabditis sp. beicherriana on the activities of superoxide dismutase (SOD), peroxidase (POD), catalase (CAT) and malondialdehyde (MDA) content of the host were studied. Last-instar larvae of Galleria mellonella were used as host insects and were experimentally infected with H. beicherriana at 0, 20, 40, 80 infective juveniles (IJs) per insect. At 0, 8, 16, 24, 32 and 40 h after infection, activities of SOD, POD, CAT and MDA content were determined in extracts from infected and control insects. We found that H. beicherriana infection resulted in gradually increased activities of SOD, POD and CAT the first day and decreased activities of these enzymes thereafter. However, MDA content in the insects of both control and IJ-inoculated groups stayed at a similar level at 24 h post-infection, but a significant decrease of MDA content in inoculated groups was recorded after 32 h of the infection, which is 8 hours later than the activities of SOD, POD and CAT were significantly increased. Our results suggest that H. beicherriana infection increases the level of oxidative stress and antioxidative responses in the larval G. mellonella, and it seems that oxidative damage contributes to cell death in this host. [ABSTRACT FROM PUBLISHER]

During our screening program for new agrochemicals from Chinese medicinal herbs, essential oil of Cayratia japonica aerial parts was found to possess strong insecticidal activities against Sitophilus zeamais and Tribolium castaneum. A total of 37 components of the essential oil were identified by gas chromatography (GC) and GC-mass spectrometry (GC-MS). Linalool (19.4%), trans-α-ionene (11.4%), α-terpineol (7.9%), dihydroactinolide (7.8%) and geranial (5.8%) were the main components of the essential oil. The essential oil exhibited strong fumigant toxicity against S. zeamais and T.castaneum adults with LC50 values of 10.05 and 15.67 mg/L air, respectively. Cayratia japonica essential oil also possessed contact toxicity against S. zeamais and T. castaneum adults with LD50 values of 32.06 and 44.49 mg/adult, respectively. The essential oil C.japonica may have potential to be developed as a new natural fumigant/insecticide for the control of stored-product insects. [ABSTRACT FROM AUTHOR]