[Controlling effects of plant extracts and pesticides on Myzus persicae and Lipaphis erysimi populations].

This paper studied the controlling effects of Xanthium sibiricum and Syngonium podophyllum ethanol extracts, mobile oil emulsion and 0.3% azadirachtin EC on Myzus persicae and Lipaphis erysimi populations both in laboratory and in field. The results showed that in laboratory, X. sibiricum extract was the key deterrent to Myzus persicae, while sprayed it with S. podophyllum extract and with petroleum spray oil or 0.3 % azadirachtin EC, the deterrent effect could be improved. As for pterigota Lipaphis erysimi, the extracts of the two plants were the main deterrents, and their interference effect was non-linear. In field, S. podophyllum extract had a stronger deterrent effect when sprayed independently. L. erysimi population could be successfully controlled by the mixtures of plant extracts and insecticides, with an efficiency of 95.7%. The best treatment against M. persicae population was X. sibiricum extract, with an efficiency of 87%, while S. podophyllum extract mixed with 0.3% azadirachtin EC, and X. sibiricum extract mixed with 0.3% azadirachtin EC had an efficiency of >80%.

[Control effects of Mikania micrantha alcohol extract on citrus red mite Panonychus citri].

This study showed that spraying 0.2 and 0.4 g x L(-1) Mikania micrantha alcohol extracts on Panonychus citri could significantly decrease the survival rates of P. citri eggs, larvae and nymphs, and 0.1 g x L(-1) M. micrantha alcohol extract could also significantly decrease the survival rates of larvae and nymphs. In a no-choice test, both the fecundity and the longevity of female P. citri fed on the leaves treated with all three test concentrations 0.1, 0.2 and 0.4 g x L(-1) of M. micrantha alcohol extracts were significantly reduced, compared with those fed on alcohol-treated leaves. In a field experiment, the efficacy of M. micrantha alcohol extracts at three test concentrations was compared with water, alcohol, and 15% Pyridaben, an acaricide widely used in commercial control of red mite in sweet orange orchards. The survival rates of P. citri eggs, larvae and nymphs in all three M. micrantha treatments were lower than the control, and the interference index of population control (IIPC) was 0.518, 0.292 and 0.277, respectively, while the IIPC for the Pyridaben treatment was 0.945, with a control efficacy of only 5.52%. M. micrantha extract had an increased control effect with its increasing concentration, and was safer to natural enemies than 15% Pyridaben. The leaves in the three M. micrantha treatments were less damaged, and their color was much deeper than that of the other three treatments. Therefore, M. micrantha alcohol extract provided a better control of citrus red mite populations than Pyridaben.

[Bioassay on oviposition repellency of non-preferable plant extracts against citrus red mite Panonychus citri].

The oviposition repellency of the alcohol extracts from 50 species of non-preferable plants and azadirachtin against citrus red mite (Panonychus citri) was determined using laboratory bioassays. In choice tests, the extracts from 42 of the 50 plant species and 1% azadirachtin (2000 x) significantly reduced oviposition 1d after treatment. The repellency effect of the extracts from the 42 plant species was better than that of azadirachtin. Mikania micrantha extract had the best result, with an Interference Index of Population Control (IIPC) of 0.087 1 d after treatment, and significantly reduced oviposition for 9 d, while the extracts from Sesbania cannabina, Allium tuberosum, Paederia scandens, Duranta erecta and Dicranopteris pedata also had good effects, with an oviposition repellency of over 70% 1 d after treatment, and significantly reduced oviposition for 4-6 d. The effect became weaker as time went on. None of the extracts showed significant oviposition attraction.