Influence of pesticides on yeasts colonizing leaves

The effect of nine different pesticides on the growth of yeasts isolated from the leaves of fruit and forest trees was investigated. Four insecticides (with the active ingredients: thiacloprid, deltamethrin, lambdacyhalothrin, and thiamethoxam) and five fungicides (with the effective substances: bitertanol, kresoxim-methyl, mancozeb, trifloxystrobin, and cupric oxychloride) were tested. The concentrations of chemicals were those recommended by the manufacturers for the spraying of trees. The yeast strains isolated from the leaves of fruit trees were not sensitive to any of the insecticides. The majority of yeast strains isolated from the leaves of forest trees were either not sensitive or only to a small extent. While Rhodotorula mucilaginosa and Pichia anomala were not affected by any insecticide, the strains of Cryptococcus laurentii and Rhodotorula glutinis showed the highest sensitivity. The effects of fungicides on the growth of isolated yeasts were more substantial. The fungicide Dithane DG (mancozeb) completely inhibited the growth of all yeasts. All strains isolated from fruit tree leaves were more resistant to the tested fungicides than those isolated from the leaves of forest trees. The most resistant strains from the leaves of fruit trees belonged to the species Metschnikowia pulcherrima, Pichia anomala, and Saccharomyces cerevisiae, whereas Cryptococcus albidus and C. laurentii, originating from the leaves of forest trees, showed the highest sensitivity to fungicides.     

Pyrethroid resistance in Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) and implications for its management in Australia

Abstract  The study was conducted to characterise the underlying resistance mechanisms responsible for high levels of pyrethroid resistance in Frankliniella occidentalis (Pergande) in Australia. Seven commercially available pyrethroids (acrinathrin, alpha-cypermethrin, bifenthrin, deltamethrin, esfenvalerate, permethrin and tau-fluvalinate) were evaluated against seven F. occidentalis strains collected from ornamentals, fruit and vegetables in three states of Australia. A Potter spray tower was used to test for pyrethroid resistance and all field strains were found to be resistant, with resistance ratios ranging from 15-fold deltamethrin to 1300-fold tau-fluvalinate. The two most resistant strains were further tested for detoxification enzymes that could be involved in resistance. Three synergists, piperonyl butoxide (PBO), diethyl maleate (DEM) and profenofos, which, respectively, inhibit the enzymes cytochrome P-450 monooxygenases, glutathione S -transferases and esterases, were used. The synergism data indicate that multiple mechanisms may be involved in pyrethroid resistance in Australian populations of F. occidentalis . Among the three synergists, PBO considerably reduced pyrethroid resistance in the selected strains compared with DEM and profenofos. The practical implication for PBO use to suppress pyrethroid resistance in F. occidentalis is elaborated.     

番茄斑萎病毒对多杀菌素抗性西花蓟马发育繁殖和药剂敏感性的影响

【目的】西花蓟马Frankliniella occidentalis (Pergande)是重要的入侵害虫,是番茄斑萎病毒（TSWV）最有效的传播媒介,TSWV对西花蓟马的生长发育有一定的影响。多杀菌素是防治西花蓟马最有效的药剂之一,但已有田间西花蓟马对多杀菌素产生抗药性的报道。TSWV对抗性西花蓟马是否也有影响及程度如何尚不清楚。本研究通过对此问题进行深入研究,以期为进一步了解TSWV对西花蓟马的影响提供依据。【方法】应用特定年龄-龄期及两性生命表的方法,研究用番茄斑萎病毒处理和未处理的多杀菌素抗性和敏感西花蓟马种群的生物学特性;用叶管药膜法测定不同处理种群对3种药剂（多杀菌素、甲氨基阿维菌素苯甲酸盐和虫螨腈）的敏感性变化。【结果】对于抗性品系,TSWV处理后西花蓟马的发育历期缩短,雌成虫寿命和产卵量略高,但与对照组差异不显著(P＞0.05),内禀增长率（r）和净生殖率（R₀）分别为0.0433 d^-1和2.210,显著高于对照组（分别为0.0356 d^-1和1.972）（P ≤ 0.001）。对于敏感品系,TSWV处理后西花蓟马的发育历期缩短,雌雄成虫寿命均显著延长（P ≤ 0.001）,产卵量也略有提高,R₀为4.125,显著高于对照组（3.979）（P ≤ 0.001）。TSWV处理后敏感和抗性西花蓟马对多杀菌素的敏感性没有发生明显变化,对甲氨基阿维菌素苯甲酸盐和虫螨腈的敏感性显著降低。【结论】番茄斑萎病毒对多杀菌素敏感和抗性西花蓟马均有直接有利影响,病毒处理的西花蓟马发育历期缩短,繁殖能力增强,成虫寿命延长,对药剂的敏感性降低。     

Luciferin-luciferase assay of adenosine triphosphate from bacteria: a comparison of dimethylsulphoxide (DMSO) and acetone with other solvents

The extraction of adenosine triphosphate (ATP) from six strains of bacteria, chosen for differences in cell-wall composition and habitat, was performed. The solvents were two in common use, Tris-ethylenediaminetetraacetate (Tris-EDTA) and trichloroacetic acid (TCA), and two promising, though less utilized solvents, dimethylsulphoxide (DMSO) and acetone. ATP was determined by the luciferin-luciferase reaction. Of the solvents used, DMSO and acetone were the most effective considering the different kinds of bacteria tested and, of these two, DMSO was the most convenient to use. Tris-EDTA was not as effective as the other solvents tested and TCA, which was effective with most strains, gave low yields when used with cultures grown in artificial seawater broth. Internal standards were used to determine if there were substances present that could inhibit the reaction of released ATP with the luciferin-luciferase reagent. Extracts of ATP, stored at -20 degrees C, were stable for up to 3 weeks.     

Sensitivity of Clonostachys rosea and Trichoderma spp. as Potential Biocontrol Agents to Pesticides

Clonostachys rosea 47 (CR47), Trichoderma atroviride 59 (TA59), T. atroviride 312 (TA312), Trichoderma harzianum 24 (TH24), Trichoderma longibrachiatum 9 (TL9), T. longibrachiatum 144 (TL144) and Trichoderma viride 15 (TV15) were tested to evaluate their in vitro sensitivity towards five fungicides (carboxin, guazatine, prochloraz, thiram and triticonazole) and four herbicides (chlorsulfuron, chlorotoluron, flufenacet and pendimethalin). All antagonists showed low sensitivity to carboxin and thiram and high sensitivity to prochloraz. For mycelial radial growth, TV15 was highly sensitive to guazatine, prochloraz and triticonazole and TH24 moderately insensitive to carboxin, guazatine and thiram. For conidial germination TL144 was the most sensitive to the fungicides, for mycelial radial growth and conidial germination CR47 was the least sensitive. None of the antagonists showed any mycelial radial growth inhibition in presence of the herbicides at field dose, except for TL144. Most antagonists did not show any conidial germination inhibition by the herbicides. The in vitro toxicity of prochloraz, guazatine and triticonazole towards the antagonists was confirmed by light and scanning electron microscope showing hyphal disruptions and extrusion of cytoplasmic content. A mixture of CR47 and/or TA312 with carboxin, thiram and triticonazole, applied to wheat seeds, was able to control Fusarium culmorum artificially inoculated to wheat seedlings in growth chambers. In the field, the antagonists applied along with triticonazole or thiram, at 1/10 of the field dose to seeds naturally infected by F. culmorum, gave a disease control comparable to that induced by triticonazole at full field dose. Our results demonstrate how an integration of microorganisms with pesticides makes the control of wheat foot rot possible.     

A comparative study of the non-acidic chemically mediated antifoulant properties of three sympatric species of ascidians associated with seagrass habitats

The present study investigated aspects of the antifoulant properties of three sympatric species of ascidians found in seagrass habitats of the Gulf of Mexico, Southern Atlantic Ocean, and Caribbean. Field observations in Saint Joseph Bay, Florida indicate that all three species are common and that the tunic of the solitary ascidian Molgula occidentalis is often heavily fouled, while the outer surfaces of both the colonial ascidians Amaroucium stellatum and Botryllus planus are free of fouling organisms. Antifoulant activities of a suite of increasing hydrophilic organic extracts prepared from the tunic of M. occidentalis and whole colonies of A. stellatum and B. planus were measured using both sympatric microbial (bacteria) and macroinvertebrate (cyprid larvae of Balanus amphitrite) fouling organisms in laboratory bioassays. In addition, field antifoulant assays were conducted by combining organic extracts with controlled-release resin and subsequently coating this material on to acrylic rods deployed in the field for a 72 h period. Extracts of the tunic of M. occidentalis generally did not inhibit bacterial growth. The exception was the methanol extract, which inhibited growth in one of the six marine bacteria tested. Moreover, only the highest concentrations of hexane and methanol tunic extracts tested prevented attachment of cyprid larvae. Field assays revealed no antifoulant activity on rods coated with resin containing extracts of M. occidentalis. Inhibition of both microbial growth and cyprid settlement were much more pronounced in whole-organism extracts of the two colonial ascidians. Most potent were the aqueous methanol extracts of colonies of B. planus and A. stellatum which inhibited growth in five of the six marine bacteria tested. In addition, hydrophilic and lipophilic extracts of the colonial ascidians significantly inhibited attachment of cyprid larvae, in many instances across a wide range of extract concentrations. Field antifoulant assays indicated that extracts of both colonial ascidians inhibited settlement of bryozoans and barnacles. The findings indicate that the colonial ascidians B. planus and A. stellatum possess chemical antifoulant properties. In contrast, the solitary ascidian M. occidentalis appears to either tolerate fouling or possess other non-chemical mechanisms to cope with the risks associated with epibiont overgrowth.     

Sensitivity to prochloraz in populations of the eyespot fungus, Pseudocercosporella herpotrichoides, in relation to fungicide treatments and their efficacy in continuous winter wheat

Eyespot was assessed and grain yields determined in the eighth and ninth years (1992 and 1993) of a field experiment in which the fungicides carbendazim and prochloraz were applied, separately or in mixtures, to plots of successive crops of winter wheat. Populations of the eyespot fungus, Pseudocercosporella herpotrichoides, were characterised by the proportions of cultures grown on agar from infected stems that were W-type or R-type, or were carbendazim-resistant or carbendazim-sensitive. Sensitivity to prochloraz in agar was determined for isolates from populations sampled in 1992 using restricted maximum likelihood analysis of EC50s (concentrations needed to decrease colony growth by 50%), to deal with the unbalanced data, and comparisons were made by Wald statistics. Control by prochloraz was maintained but in 1992, as in some previous years, its application with carbendazim was more effective than its application alone. Selection by prochloraz for strains sensitive to carbendazim continued to occur and may have contributed to its sometimes relatively poorer performance in the absence of carbendazim. R-type isolates taken from prochloraz-treated plots, with or without carbendazim, in 1992 were less sensitive to prochloraz than were isolates from plots untreated with prochloraz. There was evidence of a greater range of sensitivities to prochloraz in R-type than in W-type isolates (although some uncertainty results from the small numbers of W-type isolates obtained from some treatments), which would explain the selection of the R-type by prochloraz. The significance of these findings to modern wheat growing practices is considered.     

Chemical control of Western Flower Thrips (Frankliniella occidentalis Pergande)

Fifty-one pesticides currently registered for use in the UK were tested in the laboratory against Western Flower Thrips (Frankliniella occidentalis) maintained on chrysanthemum leaf discs. In an initial screening trial of the pesticides against larval thrips, 14 caused more than 75% mortality three days after exposure. These were tested further against adults and pupae and retested against larvae. A series of glasshouse trials were conducted using the most efficacious pesticides evaluated earlier. Granular and systemic compounds were included in the glasshouse trials since these could not be evaluated satisfactorily in the laboratory. Malathion proved to be the most potent chemical currently registered for control of thrips on a wide range of horticultural crops.     

乙基多杀菌素多代胁迫对西花蓟马解毒酶活性、发育和繁殖的影响

【目的】乙基多杀菌素是防治蔬菜上西花蓟马Frankliniella occidentalis的首选药剂之一。本研究旨在明确乙基多杀菌素多代胁迫对西花蓟马的影响。【方法】采用浸叶法以LC₂₅浓度的乙基多杀菌素对西花蓟马2龄若虫连续汰选6代后,测定其抗药性和解毒酶活性的变化,并用年龄-阶段两性生命表分析LC₂₅浓度乙基多杀菌素对西花蓟马后代(F₇)生命表参数的影响。【结果】LC₂₅浓度的乙基多杀菌素对西花蓟马2龄若虫连续汰选6代后,与用清水处理的对照相比,抗性倍数达到了6.4倍;F₆代2龄第2天若虫体内羧酸酯酶(CarE)和谷胱甘肽-S转移酶(GSTs)被激活,活性分别增加至对照的1.26和1.21倍;而多功能氧化酶(MFOs)和细胞色素P450酶(P450s)受到明显的抑制,活性分别只有对照的54.00%和51.78%。LC₂₅浓度的乙基多杀菌素胁迫6代不仅造成西花蓟马雌成虫寿命(19.33 d)和单雌产卵量(69.80粒)较对照(分别为21.60 d和83.17粒)显著下降,且后代(F₇)的雌成虫寿命(16.82 d)和雄成虫寿命(8.29 d)较对照(分别为20.28 d和10.86 d)极显著缩短,单雌产卵量(59.23粒)较对照(76.96粒)极显著降低,但雌雄比(2.28)较对照(1.03)显著提高,种群生命参数净增殖率(R₀)、内禀增长率(r)和周限增长率(λ)则无明显变化。【结论】在LC₂₅浓度乙基多杀菌素连续汰选6代内西花蓟马对该药剂的抗性缓慢增长;药剂胁迫不仅对西花蓟马解毒酶活性有不同程度的影响,还对其发育和繁殖具有一定的抑制作用。     

Influence of pesticides on the growth of cyanobacteria.

Two unicellular and two filamentous cyanobacteria (blue-green algae) were exposed under conditions optimal for photoautotrophic growth to eleven pesticides. Low concentrations (0.01 to 5 ppm) of diuron, atrazine, and paraquat inhibited growth. With MCPA, MCPP, 2,4-D, milstem and ethrel, marked inhibitory effects were achieved only at concentrations above 100 ppm. Growth was inhibited by glyphosate, DDT, and thiram at intermediate concentrations. In some cases, the effective concentration of the pesticide varied considerably with the organism tested.     

In vitro evaluation of antibacterial substances produced by bacteria isolated from different marine organisms

Bacteria from several groups of marine organisms were isolated and, using direct antibiograms, identified those that produce antibacterial substances, using a human pathogenic strain of Staphylococcus aureus ATCC6538 as revealing microorganism. Bacteria which produce substances that inhibited S. aureus growth were identified through morphological, physiological and biochemical tests. Out of 290 bacteria, 54 (18.6%) inhibited the growth of S. aureus, but only 27 survived for identification. Bivalves, sponges and corals were the most represented from which 41.2, 33.3 and 29.7%, respectively, produced antibacterial substances of the isolated bacteria in each group. The marine species with highest proportions of these bacteria were the hard coral Madracis decactis (62.5%), the sponges Cliona sp. (57.1%) and the octocoral Plexaura flexuosa (50.0%). Out of the 27 strains that produced antibacterial substances, 51.8% were Aeromonas spp. and 14.8% Vibrio spp. Marine bacteria that produce antibacterial substances are abundant, most belong in the Vibrionacea group and were isolated mainly from corals and bivalve mollusks.     

In vitro effect of phenolic antioxidants on germination, growth and aflatoxin B accumulation by peanut Aspergillus section Flavi

AIMS: The effectiveness of the food-grade antioxidants butylated hydroxytoluene (BHT), trihydroxybutyrophenone (THB), propyl paraben (PP) and butylated hydroxyanisole (BHA) at 1, 10 and 20 mmol l(-1) concentrations on germination, growth, and aflatoxin B(1) (AFB(1)) production by Aspergillus section Flavi strains was determined. METHODS AND RESULTS: Assays on the lag phase of germination, germination percentage, germ tube elongation rate, lag phase, growth rate and AFB(1) production by three strains of Aspergillus flavus and three of Aspergillus parasiticus were carried out in vitro on peanut extract meal agar conditioned at different water activities (a(w): 0.982, 0.971, 0.955, 0.937). The antioxidants PP and BHA efficiently inhibited the germination of the two species tested at the doses 10 and 20 mmol(-1). The antioxidants PP and BHA at 1 mmol l(-1) and THB at 20 mmol l(-1) reduced the germ tube elongation rate most effectively, regardless of a(w) levels. An increase in the lag time and a reduction in the growth rate of 100% of the strains was observed, this was due to the action of BHT at the doses 10 and 20 mmol(-1) at 0.982, 0.971 and 0.955 a(w), although these treatments stimulated the AFB(1) accumulation in most of the fungi tested. The more effective antioxidants were PP and BHA, which increased the lag phase, reduced the growth rate and AFB(1) production in all of the strains at the four a(w) assayed. At concentrations 10 and 20 mmol l(-1), these antioxidants totally inhibited fungal development. CONCLUSIONS: The study shows that the antioxidants BHA and PP are effective fungal inhibitors to peanut Aspergillus section Flavi in wide range of water activity. SIGNIFICANCE AND IMPACT OF THE STUDY: The results suggest that phenolic antioxidants, BHA and PP, can be effective fungitoxicants on aflatoxigenic strains in peanut at industrial level.     

喷施农药对银耳生长的影响及膳食暴露风险评估

为制订银耳(Tremella fuciformis)栽培中农药合理使用的建议,以我国银耳主栽菌株Tr01为对象,研究8组常用农药对其生长的影响,采用食品安全指数法评估长期膳食银耳导致的农药残留慢性暴露健康风险.结果表明,除咪鲜胺乳油和哒螨灵、啶虫脒微乳剂的部分处理外,其余6组农药对银耳子实体生长并无显著影响.银耳中的农...     

Antibacterial activity in the hemolymph of myriapods (Arthropoda)

The hemolymphs of two diplopod (Chicobolus sp. and Rhapidostreptus virgator) and two chilopod species (Lithobius forficatus and Scolopendra cingulata) were tested for the presence of antibacterial substances using Petri dish tests. The native hemolymph of all species had substances acting on living Micrococcus luteus, whereas only Rhapidostreptus, Scolopendra, and Lithobius were effective against lyophilized Micrococcus. The antibacterial activity against living Micrococcus increased after inoculation with bacteria (Enterobacter cloacae beta-12) in Chicobolus and Rhapidostreptus and also against lyophilized Micrococcus in the latter. Thus, these effects appear to be inducible. None of the myriapods tested had any bacteriostatic effect on Escherichia coli D-31 whereas the growth of gram-negative E. cloacae was inhibited. The antibacterial substances in the diplopod species were unstable when heated but were resistant to freezing. At least two antibacterial substances (a lysozyme-like one and another substance) are considered to occur in Myriapoda.     

In vitro control of growth and fumonisin production by Fusarium verticillioides and F. proliferatum using antioxidants under different water availability and temperature regimes

AIMS: To examine the effect of butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), trihydroxybutyrophenone and propylparaben (PP) (at concentrations of 1-20 mmol l(-1)) on growth of and fumonisin production by Argentinian strains of Fusarium verticillioides and F. proliferatum. METHODS AND RESULTS: Studies on lag phases prior to growth, relative growth rates and fumonisin concentrations were carried out in vitro in relation to water activity (0.995-0.93 a(w)) and temperature (18 and 25 degrees C) on a maize meal agar. Overall, PP was the antioxidant which was most effective at inhibiting strains of both species. The lag phase prior to growth and growth rates were significantly decreased by PP and BHA at 10 and 20 mmol l(-1), regardless of the temperature or aw level tested. Total fumonisin production was higher at 0.98 a(w) and decreased by about 45-50% at 0.995 and 0.95 a(w). Overall, BHT only inhibited fumonisin production at 0.95 aw at 10 and 20 mmol l(-1), while BHA was effective at most a(w) levels tested at 10 and 20 mmol l(-1). Propylparaben completely inhibited fumonisin production by both F. verticillioides and F. proliferatum at > 1 mmol l(-1), regardless of the temperature or a(w) level. Small interstrain differences in the levels of inhibition by the antioxidants were observed for three F. verticillioides and four F. proliferatum strains at 0.995, 0.98 and 0.95 a(w). Propylparaben and BHA completely inhibited the growth of both species at the concentrations evaluated, regardless of the a(w) level. CONCLUSIONS: Two antioxidants show promise for the control of growth of and fumonisin production by these species over a wide range of environmental conditions. SIGNIFICANCE AND IMPACT OF THE STUDY: Potential exists for using such food-grade preservatives for prevention of mycotoxigenic fungi and their toxins entering the food chain.     

Screening of plant extracts for antimicrobial activity against bacteria and yeasts with dermatological relevance

There is cumulative resistance against antibiotics of many bacteria. Therefore, the development of new antiseptics and antimicrobial agents for the treatment of skin infections is of increasing interest. We have screened six plant extracts and isolated compounds for antimicrobial effects on bacteria and yeasts with dermatological relevance. The following plant extracts have been tested: Gentiana lutea, Harpagophytum procumbens, Boswellia serrata (dry extracts), Usnea barbata, Rosmarinus officinalis and Salvia officinalis (supercritical carbon dioxide [CO2] extracts). Additionally, the following characteristic plant substances were tested: usnic acid, carnosol, carnosic acid, ursolic acid, oleanolic acid, harpagoside, boswellic acid and gentiopicroside. The extracts and compounds were tested against 29 aerobic and anaerobic bacteria and yeasts in the agar dilution test. U. barbata-extract and usnic acid were the most active compounds, especially in anaerobic bacteria. Usnea CO2-extract effectively inhibited the growth of several Gram-positive bacteria like Staphylococcus aureus (including methicillin-resistant strains - MRSA), Propionibacterium acnes and Corynebacterium species. Growth of the dimorphic yeast Malassezia furfur was also inhibited by Usnea-extract. Besides the Usnea-extract, Rosmarinus-, Salvia-, Boswellia- and Harpagophytum-extracts proved to be effective against a panel of bacteria. It is concluded that due to their antimicrobial effects some of the plant extracts may be used for the topical treatment of skin disorders like acne vulgaris and seborrhoic eczema.     

西花蓟马在6种蔬菜寄主上的实验种群生命表

自西花蓟马Frankliniella occidentalis传入我国后,该虫对蔬菜寄主的危害趋于严重,组建了25℃条件下,西花蓟马在黄瓜、甘蓝、莴苣、茄子、芹菜和大蒜叶片的实验种群生命表,以研究西花蓟马的危害差异性,为西花蓟马的防治提供基础数据。结果表明西花蓟马的生长发育、繁殖和生命表参数等在不同寄主之间有明显差异。西花蓟马在黄瓜上发育最快,其未成熟期为11.43 d,同时在黄瓜上最先开始产卵,产卵前期为1.22 d,在芹菜上发育最慢,为16.11 d。其每雌每天在甘蓝上和莴苣上产卵量最大,分别为2.88粒和2.48粒,在大蒜上最小,为0.77粒;每雌每天产雌率、子代雌性比在甘蓝和莴苣上都大于其他寄主。雌虫寿命在甘蓝上最长(29.06 d)、雄虫寿命在莴苣上最长(13.22 d)。西花蓟马在黄瓜、莴苣、茄子、甘蓝、芹菜和大蒜上的内禀增长力rm值分别为0.1318、0.1228、0.1154、0.1197、0.0860和0.0791;净增殖率R0分别为19.1248、30.8523、17.9322、34.5322、8.9491和8.3536。种群趋势预测指数(I)在甘蓝(34.17)、莴苣(30.09)上明显高于其它寄主,在芹菜(8.00)和大蒜(8.22)上最低。     

Efficacy of entomopathogenic nematodes against soil-dwelling life stages of western flower thrips, Frankliniella occidentalis (Thysanoptera: Thripidae).

The efficacy of six entomopathogenic nematode (EPN) strains was tested in a laboratory study against soil-dwelling life stages of western flower thrips (WFT), Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). The EPN strain collections screened included two Heterorhabditis bacteriophora species, i.e., H. bacteriophora HK3 (H.b H) and H. bacteriophora HB Brecan (H.b B), three Steinernema feltiae species, i.e., S. feltiae Sylt (S.f S), S. feltiae OBSIII (S.f O), and S. feltiae strain CR (S.f C), and the S. carpocapsae strain DD136 (S.c D). All soil-dwelling life stages of WFT were susceptible to the tested EPN strains. The most virulent strains were S.f S, S.c D, and H.b H. The S.f O strain was highly virulent against late second instar larvae and prepupae of WFT under high soil moisture conditions, but less effective against pupae under comparatively drier soil conditions. Results from dose rate experiments indicate that a comparatively high concentration of 400 infective juveniles (IJs) per cm(2) was needed to obtain high mortality in all soil-dwelling life stages of WFT. However, dose rates of 100-200 IJs/cm(2) already caused 30-50% mortality in WFT. The chances for combining EPNs with other biological control agents of WFT are discussed.     

Insecticide resistance in Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) collected from horticulture and cotton in Turkey

Abstract  The sensitivity of three reference strains of the western flower thrips Frankliniella occidentalis from Australia, Israel and Turkey was evaluated and their response did not differ significantly and so they are considered typical of susceptible F. occidentalis . Field strains of F. occidentalis from Antalya, Turkey were tested for resistance against five classes of insecticide during the years 2001–2003. Difference in the field strains response to abamectin, endosulfan, malathion and methomyl was low (<3.0-fold) and in many cases not significant. However, all strains were likely resistant to cypermethrin (1.6- to 12.2-fold at LC₅₀ (lethal concentration)). The established agricultural practices and ecosystem patterns in the Antalya province are assumed to contribute to delay in insecticide resistance in F. occidentalis .     

Antimicrobial activity of Staphylococcus xylosus from Italian sausages against Listeria monocytogenes

One hundred and twenty-five isolates of Micrococcaceae from Italian salami were tested for antagonistic activities against Listeria monocytogenes. Four isolates, identified as Staphylococcus xylosus , inhibited the growth of all five strains of L. monocytogenes tested. The antagonistic substances produced by strains 39A and 41A were inactivated by some proteases, whereas those from strains 1E and 27E were inactivated only by esterase and lipase. They are neither bacteriophages, nor lytic enzymes like lysostaphin.