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Jin T.,South China Agricultural University | Jin T.,Key Laboratory of Monitoring and Control of Tropical Agricultural and Forest Invasive Alien Pests | Zeng L.,South China Agricultural University | Lin Y.,South China Agricultural University | And 2 more authors.
Pest Management Science | Year: 2011

BACKGROUND: In order to investigate the extent of resistance of oriental fruit fly, Bactrocera dorsalis (Hendel), which is a widespread pest throughout tropical, subtropical and temperate fruit crops, 25 populations of this insect were collected from 13 sites in mainland China in 2007 and 2008. In addition, resistant strains were established that showed increasing development of resistance. RESULTS: Compared with the susceptible strain, one population of B. dorsalis expressed high resistance (RR = 70.4-fold), 16 populations expressed medium resistance (11.5-fold < RR < 25.8-fold) and eight populations had low resistance or remained susceptible (1.4-fold < RR < 8.9-fold) to trichlorphon. As regards β-cypermethrin, one population showed high resistance (RR = 44.0-fold), nine populations expressed medium resistance (12.2-fold < RR < 28.4-fold), 14 populations expressed low or minor resistance (3.0-fold < RR < 9.7-fold) and one population remained susceptible (RR = 1.1-fold). As regards avermectin, five populations had developed high resistance (44.3-fold < RR < 104-fold), seven populations expressed medium resistance (11.4-fold < RR < 38.6-fold) and three populations expressed low or minor resistance (3.5-fold < RR < 5.6-fold). A continuous resistance selection in the laboratory strain showed that the resistance ratios to trichlorphon, β-cypermethrin and avermectin were 71.6-fold, 333-fold and 70.4-fold respectively. CONCLUSION: The data provided a comprehensive survey of insecticide resistance in Bactrocera dorsalis in mainland China. All results suggested that early resistance management programmes should be established for restoring the efficacy of pesticide-based control measures. © 2010 Society of Chemical Industry. Source


Feng G.,Chinese Academy of Sciences | Feng G.,Key Laboratory of Monitoring and Control of Tropical Agricultural and Forest Invasive Alien Pests | Zhang J.,Chinese Academy of Sciences | Liu Y.-Q.,Lanzhou University
Natural Product Research | Year: 2011

The antifungal activities of dihydrosanguinarine and dihydrochelerythrine, isolated from the leaves of Macleaya microcarpa, were evaluated on 12 plant pathogenic fungi; the two compounds exhibited the highest antifungal activity against Botrytis cinerea Pers. Among the 11 tested plant pathogenic fungi in vitro, the two compounds showed the highest antifungal activity against B. cinerea Pers, with 95.16% and 98.32% mycelial growth inhibition at 50μgmL -1, respectively. In addition, the two compounds inhibited spore germination in vitro in a concentration-dependent manner. They also showed potent protective and curative effects against Erysiphe graminis and B. cinerea in vivo. This is the first report on the antifungal activity of dihydrosanguinarine and dihydrochelerythrine against pathogenic plant fungi. © 2011 Taylor & Francis. Source


Zhang J.,Chinese Academy of Sciences | Zhang J.,Key Laboratory of Monitoring and Control of Tropical Agricultural and Forest Invasive Alien Pests | Yan L.-T.,Lanzhou University | Yuan E.-L.,Chinese Academy of Sciences | And 12 more authors.
Journal of Agricultural and Food Chemistry | Year: 2014

Cortex Pseudolaricis is the root bark of Pseudolarix amabilis Rehder, found only in China, and has been widely used in folk antifungal remedies in traditional Chinese medicine. In order to find the natural antifungal agents against mango anthracnose, eight compounds, namely pseudolaric acid A (1), ethyl pseudolaric acid B (2), pseudolaric acid B (3), pseudolaric acid B-O-β-d-glucoside (4), piperonylic acid (5), propionic acid (6), 3-hydroxy-4-methoxybenzoic acid (7), and 4-(3-formyl-5-methoxyphenyl) butanoic acid (8) were isolated from the ethanol extracts of Cortex Pseudolaricis by bioassay-guided fractionation and evaluated for in vitro antifungal activity against Colletotrichum gloeosporioides Penz. Results demonstrated that all of the eight compounds inhibited the mycelial growth of C. gloeosporioides at 5 μg/mL. Among them, pseudolaric acid B and pseudolaric acid A showed the strongest inhibition with the EC50 values of 1.07 and 1.62 μg/mL, respectively. Accordingly, both Pseudolaric acid B and Pseudolaric acid A highly inhibited spore germination and germ tube elongation of C. gloeosporioides. Dipping 100 μg/mL pseudolaric acid B treatment exhibited more effective suppression on postharvest anthracnose in mango fruit when compared to the same concentration of carbendazim. Scanning electron microscopy observations revealed that pseudolaric acid B caused alterations in the hyphal morphology of C. gloeosporioides, including distortion, swelling, and collapse. Pseudolaric acid B caused the mycelial apexes to show an abnormal growth in dimensions with multiple ramifications in subapical expanded areas with irregular shape. These findings warrant further investigation into optimization of pseudolaric acid B to explore a potential antifungal agent for crop protection. © 2014 American Chemical Society. Source


Qi X.,Hainan University | Guo L.,Chinese Academy of Sciences | Guo L.,Key Laboratory of Monitoring and Control of Tropical Agricultural and Forest Invasive Alien Pests | Yang L.,Chinese Academy of Sciences | And 3 more authors.
Physiological and Molecular Plant Pathology | Year: 2013

We characterized Foatf1, a basic leucine zipper (bZIP) transcription factor in Fusarium oxysporum f. sp. cubense race 4 (Foc4), and created a deletion mutant of Foatf1. Foatf1 deletion mutant could cause oxidative burst of banana seedlings in early stages of infection. This mutant also showed higher sensitivity to hydrogen peroxide (H2O2) than the wild-type strain. Foatf1 significantly reduced the activity of extracellular enzymes and the transcription level of catalase. Furthermore, Foatf1 exhibited remarkably reduced virulence on Cavendish banana (Musa spp.). These findings indicated that Foatf1 could be necessary to induce the full virulence of Foc4 by regulating the transcription of catalase to impair plant defenses mediated by reactive oxygen species. © 2013 Elsevier Ltd. Source


Zhang F.,Environment and Plant Protection Institute | Zhang F.,Key Laboratory of Monitoring and Control of Tropical Agricultural and Forest Invasive Alien Pests | Zhang F.,Key Laboratory of Pests Detection and Control for Tropical Agriculture | Fu Y.,Environment and Plant Protection Institute | And 14 more authors.
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2010

Coccophagus ceroplastae is an important parasitic wasp, endoparasitizing the 2 nd and 3 rd instar larva of Parasaissetia nigra. In this paper, the morphological characteristics of C. ceroplastae were described, and behaviors, development, survival, and reproduction of the wasp were also studied in the lab. The results showed that life cycle of C. ceroplastae lasted 21 -26 days, including eggs, 3 larva instars, prepupae, pupae and adults. Duration from eggs to pupae was 14 - 17d, and that of pupae was 7-9d. The reproductive system of female was located in the abdomen, with a pair of eudipleural ovaries, and each ovary consisted of 3 ovary tubes. The ligament composed of terminal filament was separate, and didn't joint to median ligament. Ovaries started to develop in the pupa phase. Some eggs are matured in 6-day-old pupae. Mature eggs in the ovaries reached 63.9, 154.7, and 163.2 in 7-day-old pupae, adults just emerged, and adults one day later, respectively. Addition of nutritions in the adult phase had no significant effects on egg number, which indicated that C. ceroplastae is a pro-ovigenic parasitoid. Mating happened just after eclosion and lasted 2 -3 seconds, and there was mating competition behavior among male wasps. Male wasps could mate several times, but female ones could only mate once. Mating obviously promoted oviposition. An unmated and mated female wasp laid averagely 2 and 164 eggs, respectively, in the 3 rd instar nymph of P. nigra, under the same conditions, which were 82 times in the difference. C. ceroplastae oviposited after mating, and oviposition duration lasted 5-8 seconds. Oviposition behavior included host searching, host inspecting, ovipositor probing, laying eggs and ovipositor pulling out. The wasps had poor ability to distinguish between parasitized and unparasitized hosts. Superparasitism existed, and one wasp might lay eggs repeatedly in a single host, but only one egg could develop into adults. Eclosion peaked in 8:00 - 10:00am. There was a circular eclosion hole, with irregular edges, about 0. 2 -0. 6 mm in diameter, located in the back of dorsal raphe near the anal cleft of host. Temperature, relative humidity (RH), and photoperiod affected eclosion rhythm of the wasp. Eclosion peaked during 08:00 - 10: 00 AM at 20 and 24°C. Under suitable temperature, eclosion emerged intensively. Proportion of eclosion reached 89.36% and 88. 89% during 08:00 - 10:00 AM at 20 and 24°C, respectively. The peak of eclosion happened during 06: 00 -08: 00 AM at 14°C, with only 31.71% adult eclosing. Eclosion peaked during 06: 00 -08: 00 and 08: 00 - 10: 00 AM at 20% and 30% - 90% RH, respectively. At the photoperiod (L:D = 12:12), eclosion emerged intensively, with 88. 89% adult eclosing during the eclosion peak. Longer or shorter photoperiods could scatter eclosion. Temperature and addition of nutritions had significant influences on longevities of adult wasps. Female wasp lived shorter, with the increasing of temperatures. At the same temperature, addition of nutritions offered could prolong the longevities of adult wasps, and to a greater extent with the increasing of nutrition concentration. The longest-lived adult wasps were those offered 10% sucrose, secondly 10% honey, lastly offered clear water or no nutrition. Source

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