Planococcus maritimus ML1206 Isolated from Wild Oysters Enhances the Survival of Caenorhabditis elegans against Vibrio anguillarum

With the widespread occurrence of aquaculture diseases and the broad application of antibiotics, drug-resistant pathogens have increasingly affected aquatic animals’ health. Marine probiotics, which live under high pressure in a saltwater environment, show high potential as a substitute for antibiotics in the field of aquatic disease control. In this study, twenty strains of non-hemolytic bacteria were isolated from the intestine of wild oysters and perch, and a model of Caenorhabditis elegans infected by Vibrio anguillarum was established. Based on the model, ML1206, which showed a 99% similarity of 16S rRNA sequence to Planococcus maritimus, was selected as a potential marine probiotic, with strong antibacterial capabilities and great acid and bile salt tolerance, to protect Caenorhabditis elegans from being damaged by Vibrio anguillarum. Combined with plate counting and transmission electron microscopy, it was found that strain ML1206 could significantly inhibit Vibrio anguillarum colonization in the intestinal tract of Caenorhabditis elegans. Acute oral toxicity tests in mice showed that ML1206 was safe and non-toxic. The real-time qPCR results showed a higher expression level of genes related to the antibacterial peptide (ilys-3) and detoxification (ugt-22, cyp-35A3, and cyp-14A3) in the group of Caenorhabditis elegans protected by ML1206 compared to the control group. It is speculated that ML1206, as a potential probiotic, may inhibit the infection caused by Vibrio anguillarum through stimulating Caenorhabditis elegans to secrete antibacterial effectors and detoxification proteins. This paper provides a new direction for screening marine probiotics and an experimental basis to support the potential application of ML1206 as a marine probiotic in aquaculture.     

云南柠檬园橘臀纹粉蚧的发生及防治初探

对德宏柠檬产区柠檬园树体冠层和土壤耕作层橘臀纹粉蚧的发生情况及防治措施进行了研究,结果表明：橘臀纹粉蚧每年7至10月在柠檬树地上冠层部分形成一个为害期,4月和6月在地下耕作层根部形成两个为害高峰,于橘臀纹粉蚧低龄期采用10%吡虫啉可湿性粉剂2000倍液进行灌根,防治效果最好。     

大洋臀纹粉蚧和南洋臀纹粉蚧TaqMan实时荧光PCR检测方法

臀纹粉蚧属有多个种类是重要的农业害虫,大洋臀纹粉蚧(Planococcus minor(Maskell))和南洋臀纹粉蚧(Planococcus lilacius Cockerell)是我国有重要检疫意义的有害生物.这两种臀纹粉蚧经常从进口泰国和东南亚水果口岸检疫中截获,但形态学方法很难进行准确鉴定.本研究首次利用mtDNA COI基因设计了两条特异性探针,应用TaqMan实时荧光PCR方法对大洋臀纹粉蚧和南洋臀纹粉蚧进行了快速准确鉴定.     

警惕检疫性害虫大洋臀纹粉蚧在中国大陆扩散

大洋臀纹粉蚧(Planococcus minor)是一种近年来入侵我国大陆的检疫性害虫,原仅记载于我国台湾,2008年以来在广西、广东、海南、云南等地被陆续发现。该虫食性杂,为害超过250种水果、经济作物、花卉和园林植物。本文介绍了大洋臀纹粉蚧的基本信息、为害特点、生物学特性、地理分布、寄主范围、国内扩散趋势、口岸截获、风险评估以及防控措施,以期为防止该虫在中国大陆的再次传入及扩散蔓延提供科学依据。     

Preference of foraging ants (Hymenoptera: Formicidae) for bait toxicants in South African vineyards

Argentine ants Linepithema humile (Mayr), common pugnacious ants Anoplolepis custodiens (F. Smith) and cocktail ants Crematogaster peringueyi Emery are the main indirect ant pests in South African vineyards. These ants form mutualistic relationships with the vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), an economic phloem-feeding pest of vines that excretes honeydew. Ants feed on the honeydew from mealybugs and also affect predator-prey interactions by protecting them from attack by natural enemies. This consequently reduces the efficacy of predators and parasitic Hymenoptera in controlling P. ficus. Current strategies for ant control are limited to the application of long term residual insecticides that are detrimental to the environment, labour intensive to apply and potentially disruptive to biological control. Here, we report on the development of an alternative method of ant control using baits which are likely to show delayed toxicity to these ant species. Field bait preference assessments were carried out during spring, summer and autumn in three vineyards of the Cape Winelands region, Republic of South Africa during 2007/08. Preference/non-preference is the first behaviour an ant exhibits when encountering bait and this was measured in terms of numbers of ants at bait stations. Five toxicants comprising Gourmet ant bait (containing 0.5% boric acid as active ingredient and a honeydew mimic as an attractant), boric acid (0.5%), fipronil (0.0001%), fenoxycarb (0.5%) and spinosad (0.01%) all dissolved in 25% sucrose solution were tested against a 25% sucrose solution control. Gourmet ant bait was overall the most preferred bait during spring, summer and autumn, and on some occasions being significantly more preferable to ants than the control solution.     

Some biological interactions between the parasitoid <Emphasis Type="Italic">Anagyrus pseudococci</Emphasis> (Girault) (Hymenoptera: Encyrtidae) and its host <Emphasis Type="Italic">Planococcus ficus</Emphasis> (Signoret) (Hemiptera: Coccoidea: Pseudococcidae)

The development, longevity, fecundity and life-table parameters of the endoparasitoid Anagyrus pseudococci (Girault) (Hymenoptera: Encyrtidae), 15 d.o. (3rd-instar nymphs) and 21 d.o. (young adult females) of the vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae) at 28 ± 1°C, 65 ± 10%RH and 16:8h L:D under laboratory conditions. The developmental time of female parasitoids within the host was 17.7 ± 0.39 days in 15 d.o. and 16.65 ± 0.25 days in 21 d.o. hosts; for males, development time was 16.85 ± 0.29 and 15.25 ± 0.09 days, respectively. The average number of offspring per female was 22.35 ± 1.68 in 15 d.o. and 34.8 ± 2.56 in 21 d.o. vine mealybugs. The longevity of female parasitoids was 14.8 ± 0.98 days in 15 d.o. and 15.65 ± 0.92 days in 21 d.o. mealybugs, respectively; for males, longevity was determined as 7.3 ± 0.43 and 6.7 ± 0.54 days, respectively. The mean time of pupation was 7.85 ± 0.003 days in 15 d.o. mealybugs and 8.65 ± 0.003 days in 21 d.o. mealybugs. The aggregate encapsulation rate in the parasitized 15 d.o. mealybugs was 49.73 and 60.36% in 21 d.o. mealybugs. Furthermore, effective encapsulation was 24.82% in 15 d.o. mealybugs and 37.50% in 21 d.o. mealybugs. Population growth rate (r _m) for A. pseudococci was 0.0999 female/female/days in 15 d.o. mealybugs and 0.1269 female/female/days in 21 d.o. mealybugs. The mean population generation time was 23.49 days for parasitoids reared in 15-days-old and 22.39 days when reared in 21 d.o. mealybugs.     

Effect of Botanical Insecticides on the Foraging and Feeding Behavior of the Coccinellid PredatorCryptolaemus montrouzieri

To investigate the effect of botanicals on the foraging behavior of the mealybug predatorCryptolaemus montrouzieri Mulsant, predator larvae and adults were exposed to leaves and the mealybugPlanococcus citri (Risso) treated with one of the following: a crude neem seed extract; a formulation of azadirachtin (Azatin EC®); a pyrethrum extract; and one of two naphthoquinones isolated fromCalceolaria andina Benth. (BTG 504 and BTG 505). All the botanicals influenced the foraging behavior ofC. montrouzieri, at one or more concentrations. Larval and adult foraging behavior was influenced most by BTG 504 and neem also affected larval behavior; the predators contacted fewer treated leaves and spent less time on treated than on untreated leaves. Larvae also consumed fewer mealybugs treated with BTG 504 and BTG 505 compared with untreated mealybugs.     

Effect of Buprofezin onIcerya Purchasi andPlanococcus Citri

The effectiveness of buprofezin (aqueous suspensions from 25% wettable powder) on cumulative nymph mortality and reproduction of two homopterous pests,Icerya purchasi Maskell (Margarodidae) andPlanococcus citri (Risso) (Pseudococcidae), was investigated under laboratory conditions. Buprofezin was very effective against crawlers of both species. Dipping in concentrations of 0.002%, 0.01% and 0.05% (a. i.) resulted in 91–99% nymph mortality ofP. citri, whereas 100% mortality was recorded whenI. purchasi was treated at 0.05% (a. i.); the 3rd-instar nymphs ofI. purchasi were less susceptible to the chemical. Death of the larval stages occurred mainly during the molting process to the 2nd-instar nymphs. At 0.05%, buprofezin sprayed on adults slightly reduced fecundity and decreased egg hatch to 31% forI. purchasi and, depending on the exposure period of the females, to 49-7% forP. citri. Buprofezin at 0.05% exhibited strong ovicidal activity onP. citri, resulting in inhibition of over 80% egg hatch.     

Laboratory assay of the effectiveness of the entomopathogenic fungus Isaria farinosa (Holmsk.) Fries (Sordariomycetes: Hypocreales) against the vine mealybug Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), even under the use of fungicides

The vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), is one of the main pests in vineyards. At present biological control of the pest is based on the release of hymenopterous parasitoids and coccinellid predators. The effectiveness of an entomopathogenic fungus, Isaria farinosa, as an alternative biological control agent on vine mealybug P. ficus was investigated by using different inoculum densities and different relative humidity levels. The fungus caused more than 80% mortality at 95% relative humidity and at 1 × 10⁸ conidia ml^?1 inoculum density. The mortality effects of the fungus decreased in lower humidity levels and lower spore densities. The inhibitory effects of common fungicides, used in vineyards, on I. farinosa were also investigated. Sulphur, copper oxychloride, fosetyl-Al and chlorothalonil did not decrease the effectiveness of I. farinosa as a pathogen of vine mealybug. With the application of tebuconazole, penconazole and mancozeb, the most inhibitory fungicides on the entomopathogen, the mortality rates of mealybugs, inoculated with I. farinosa, decreased from 86% to 42%, 34% and 45%, respectively, in the adult females; from 94% to 51%, 45% and 45%, respectively, in the first nymphal stages; and from 86% to 56%, 49% and 63%, respectively, in ovisacs.