Infectivity of Steinernema spp. (Nematoda: Steinernematidae) to Adult Litter Beetles, Alphitobius diaperinus (Coleoptera: Tenebrionidae) in the Laboratory

Three species of Steinernema, S. carpocapsae, S. feltiae, and S. scapterisci consisting of 12 different strains, were tested for their infectivity towards adults of the litter beetle Alphitobius diaperinus. Of the five most promising nematode strains, LC₅₀ values ranged from 1.5 to 77.0 nematodes per host in the filter paper assays. Assays in poultry litter material revealed LC₅₀ values to be 5.8 and 14.6 nematodes per host for the Mexican S. carpocapsae strain and Pye S. feltiae strain.     

Virulence of entomopathogenic nematodes (Rhabditida: Steinernematidae, Heterorhabditidae) against Tipula paludosa (Diptera: Tipulidae), a turfgrass pest on golf courses

The European crane fly (ECF), Tipula paludosa Meigen feeds on leaves, crowns, and roots of cool-season turfgrasses causing damage to residential lawns and golf courses. A laboratory study was conducted to determine the susceptibility of ECF larvae to four commercial entomopathogenic nematode (EPN) species (Heterorhabditis marelatus, H. megidis, Steinernema carpocapsae and S. feltiae). The virulence of four S. feltiae isolates recovered from golf courses in Quebec and Ontario were also compared to a commercial strain. LC₅₀ values of EPN against late instar ECF larvae were 152, 562, 763, and 3584 for S. feltiae, H. megidis, H. marelatus and S. carpocapsae, respectively. When non-feeding (without grass seedling), ECF larvae mortalities decreased for all nematode species and concentrations tested. At 25°C, LC₅₀ values for the two most virulent indigenous S. feltiae were 129 and 187 nematodes/larva, not different from the commercial strain. At 5°C, the commercial S. feltiae was more effective than both BIC14A and RE6A isolates against ECF larvae. However, at 15°C, BIC14A was the most virulent at the low concentration of 200 IJs/larva.     

The Compatibility of Control Agents used for the Control of the South American Leafminer, Liriomyza huidobrensis

The compatibility of infective juveniles (IJs) of the entomopathogenic nematode, Steinernema feltiae, the parasitic wasps Diglyphus isaea and Dacnusa sibirica, and chemical insecticides to control larval stages of the South American leafminer, Liriomyza huidobrensis, on leafy salad crops was investigated. In intact leaf mines, leafminer larvae already parasitized by D. isaea which had developed to the larval or pupal stage, and D. sibirica in the larval stage were subsequently also infected by S. feltiae following a foliar application. This reduced the potential of the wasps to survive until the adult stage. In similar tests foliar applied chemical insecticides reduced the survival to adulthood of D. sibirica and their host larvae. However, a soil drench of imidaclorpid did not cause a significant reduction in the number of D. sibirica which survived the treatment and developed to adult emergence. Tests to investigate the utilisation of parasitoids following foliar applications of nematodes found that adult D. isaea did not discriminate between the healthy and nematode-infected leafminer larvae for host feeding, although 98% of eggs laid by the female wasps were deposited alongside healthy larvae.     

Osmotic Survival of the Entomopathogenic Nematode Steinernema carpocapsae

The effect of different osmolytes on the viability and the effect of osmotic pressure on the induction of a dormant state similar to that caused by a slow desiccation rate were evaluated in the entomopathogenic nematode Steinernema carpocapsae ‘All’. For both experiments, a high-temperature (45°C) assay (HTA) was employed. Exposing fresh infective juveniles to the HTA resulted in a drastic reduction in viability. Using the same assay, the mortality of desiccated nematodes was gradual, showing an enhanced ability to withstand high-temperature conditions. The patterns of decline in viability in the evaporatively dehydrated and the osmotically desiccated nematodes were similar. Most of the salts tested in the screening assay caused high mortality levels among the nematodes within the first 24 h of exposure. In contrast, the nonionic solutes tested did not hamper the viability of the infective juveniles. In these nonionic solutions, all nematodes were completely shrunk after 48 h. Furthermore, 72-h exposure to these solutions resulted in an increase in heat tolerance similar to that of the evaporatively dehydrated nematodes. A substantial increase in heat tolerance was recorded in the treatments with glycerol solutions at concentrations from 2.2 to 3.8 M. A similar effect was obtained by polyethylene glycol (PEG) 300 MW at concentrations ranging from 1.2 to 1.6 M. PEG 600 MW induced enhancement of heat tolerance at a concentration of 0.8 M. A high level of viability was attained among nematodes that were stored for 72 days following a gradual increase in glycerol concentrations. Exposure of these nematodes to 45°C in the HTA resulted in 87.3 ± 4.7 and 49.2 ± 3.9% survival after 4 and 8 h, respectively. Reduction in viability was observed among nematodes that were directly exposed to the glycerol solution over a 19-day storage period. With this treatment, survival levels of 72.7 ± 3.9 and 26.5 ± 4.7% after 4 and 8 h, respectively, were recorded in the HTA. Reduction in viability among nematodes stored in distilled water was noted after 36 days of storage. Evaluation of nematode infectivity by two criteria (insect mortality and invasion rate) indicated that infectivity of nematodes desiccated by gradual osmotic pressure induced by glycerol was similar to that of fresh nematodes after 54 days in storage at 25°C. In comparison, infectivity of nematodes stored in distilled water declined significantly compared to that of fresh nematodes.     

Compatibility of entomopathogenic nematodes with fipronil

The survival and infectivity of infective juveniles (IJs) of three species of entomopathogenic nematodes, Steinernema carpocapsae Weiser, S. arenarium (Artyukhovsky) (Rhabditida: Steinernematidae) and Heterorhabditis bacteriophora Poinar (Rhabditida: Heterorhabditidae), were determined after exposure to different concentrations (250, 500, 1000 and 2000 ppm) of fipronil, an insecticide acting on the GABA receptors to block the chloride channel. Heterorhabditis bacteriophora was very tolerant to all concentrations of fipronil, with the highest mortality of 17% being observed at 2000 ppm of fipronil after 72 h exposure. Steinernema carpocapsae showed a similar response, with the highest mortality of 11.25% of IJs being observed after 72 h exposure to 2000 ppm of fipronil. Steinernema arenarium was, however, more sensitive to fipronil, and at 2000 ppm mortality rates of 94.6% and 100% were observed after 24 and 72 h, respectively. Fipronil had negligible effects on the infectivity of the three nematode species tested. The IJs which survive exposure to all concentrations of fipronil tested can infect and reproduce in Galleria larvae. The moderate effects on entomopathogenic nematodes of a lower fipronil concentration (250 ppm) and the field rates (12-60 ppm) of fipronil used as insecticide, suggest that direct mixing of entomopathogenic nematodes and fipronil at field rates is a viable integrated pest management option.     

Biological Control of the Shore Fly (Scatella tenuicosta) with Steinernematid Nematodes and Bacillus thuringiensis var. thuringiensis in Peat and Rockwool

Steinernema feltiae Filipjev and S. carpocapsae Weiser (Nematoda: Steinernematidae) at rates of 1, 5 and 20 million m^-2 in peat pots and at rates of 1, 2.5 and 5 million m^-2 in rockwool cubes were tested against the shore fly Scatella tenuicosta Collin (Diptera: Ephydridae) by applying the nematodes either preventatively 2 days before or curatively 9 days after, or both 2 days before and 9 days after exposing the pots and cubes to flies. Based on cumulative fly numbers that emerged from peat pots sampled weekly for 3 weeks, all application strategies with 5 or 20 million nematodes net-m^-2, irrespective of species, reduced fly numbers by 61-96% as compared to untreated controls. High temperatures in 1 week reduced control efficacy to 30-35% in some treatments. In rockwool, maximum control efficacies of 83-84% were achieved by both species in the second week in treatments that had received two applications at the rate of 5 million m^-2, but these did not differ significantly from the 69-75% efficacies achieved with 2.5 million nematodes m^-2. The cumulative control efficacy over 4 weeks was only 46% at maximum. The lower control efficacy in rockwool compared to peat was due to rapid disappearance of nematodes from rockwool.     

Latent infection: a low temperature survival strategy in steinernematid nematodes

1. Entomopathogenic nematodes penetrate and kill Galleria mellonella within 48 h at optimal temperatures.

2. Low temperature induces infection latency, preventing host death until optimal conditions resume.

3. Infected Galleria survived 25 days at 5°C. On transfer to 25°C, 100% and 12.5% of Steinernema carpocapsae and Steinernema riobravis infected larvae died within 72 h.

4. Infective juvenile penetration decreased with decreasing temperature; declining from 49.7 and 49.3 nematodes/host at 25°C to 6.3 and 0.25 nematodes/host at 5°C for S. carpocapsae and S. riobravis, respectively.

5. Latent infection occurs, albeit infrequently, due to low host penetration at low temperature.

The nature of the intestinal vesicle in nematodes of the family steinernematidae

The intestinal vesicle is a modification of the ventricular portion of the intestine of infective larvae of nematodes of the family Steinernematidae. This structure, which normally houses the bacterium Xenorhabdus nematophilus in Steinernema species, was examined in a number of species either in the living state using differential interference contrast optics or in sections under the electron microscope. In Steinernema bibionis and S. kraussei the vesicle was found to be a thick walled, tapered structure packed with bacteria. In S. glaseri the wall of the vesicle was more irregular in thickness and the bacteria were not so tightly packed, whilst in S. feltiae the wall was thinner still. Development of the vesicle is not dependent on the presence of bacteria; a similar but empty structure was produced in axenically grown infective larvae of S. bibionis. The vesicle of an undescribed steinernematid designated Q1 was found to differ substantially from those mentioned above in that it had distinct microvilli. The lumen of this structure was filled with an amophorus matrix in which bacteria were embedded some distance apart from each other. There appears to be considerable variation in the morphology of the intestinal vesicle in the infective larvae of different steinernematids.     

噻虫嗪处理的芫菁夜蛾斯氏线虫SF-SN对韭菜迟眼蕈蚊幼虫的杀虫效果和搜寻效应

【目的】昆虫病原线虫受到化学农药作用后,其对害虫的杀虫效果和搜寻效应可能会发生变化。本研究旨在探讨噻虫嗪处理的昆虫病原线虫对韭菜迟眼蕈蚊Bradysia odoriphaga幼虫(韭蛆)的杀虫效果及搜寻效应的影响。【方法】采用培养皿滤纸法,通过功能反应试验测定了噻虫嗪(15 mg/L)处理的芫菁夜蛾斯氏线虫Steinernema feltiae SF-SN (Sf)对韭蛆3龄幼虫的致死率和搜寻效应,比较噻虫嗪处理的Sf和未处理的Sf致死功能反应和搜寻效应的差异。【结果】噻虫嗪处理的Sf引起的韭蛆3龄幼虫的校正死亡率高于未处理的Sf引起的校正死亡率,处理6 h时,较未处理的Sf引起的校正死亡率提高了2.13倍。当Sf浓度固定在6 400 IJs/皿时,噻虫嗪处理的和未处理的Sf对该试虫功能反应均拟合Holling Ⅱ和Ⅲ型方程,与未处理的Sf相比,噻虫嗪处理的Sf对该试虫的攻击率(a′=0.5592)提高了42.46%,线虫寻找、寄生及致死该试虫所花费的总时间即处理时间(T_h=0.0081 d)则降低了44.90%,消耗率(a′/T_h)提高了2.59倍,日最大致死量(Na_max)则分别提高了1.81倍(Holling Ⅱ)和1.41倍(Holling Ш)。而噻虫嗪处理的和未处理的Sf对该试虫的搜寻效应均随韭蛆密度的增加而呈线性下降。当韭蛆密度固定在40头/皿时,噻虫嗪处理的和未处理的Sf对该试虫的致死效果均随着韭蛆密度的增加而增大,搜寻效应则均先上升后下降,且噻虫嗪处理的Sf的寻找参数和相互干扰参数均高于未处理Sf的。【结论】噻虫嗪处理的Sf对韭蛆3龄幼虫的校正死亡率、瞬时攻击率、消耗率、日最大致死量和搜寻效应均高于未处理Sf的,而处理时间则显著降低。     

敌百虫对中肋骨条藻生长的影响

研究了有机磷农药敌百虫对中肋骨条藻Skeletonema costatum生长的影响。相对于水生甲壳类和鱼类,敌百虫对中肋骨条藻毒性较低,72 h半抑制浓度(EC₅₀)为84.8 mg/L。在31 d的亚慢性暴露下,低浓度组(≤10 mg/L)藻细胞生长趋势与对照组相似;50 mg/L的敌百虫在暴露初期对骨条藻的生长具有明显抑制作用,但在暴露15 d后,该浓度组藻细胞密度仍保持增长,最大细胞密度为2.77×10⁷ cells/mL,是对照组的137.7%。100 mg/L则能完全抑制藻细胞的生长。本实验结果说明敌百虫等有机磷农药的广泛使用可能会刺激浮游植物的生长,从而增加引发赤潮的风险。     

Synergistic effect of the herbicides glyphosate and MCPA on survival of entomopathogenic nematodes

The survival and infectivity of the infective juveniles of two species of entomopathogenic nematodes, Steinernema feltiae (Rhabditida: Steinernematidae) Heterorhabditis bacteriophora (Rhabditida: Heterorhabditidae), were determined after exposure for 72 h to two concentrations of the herbicides glyphosate and MCPA, as well as to the combination of the two herbicides (glyphosate + MCPA). For all herbicide treatments, concentrations and exposure times, S. feltiae was more tolerant to the herbicides than H. bacteriophora. The exposure of entomopathogenic nematodes to glyphosate + MCPA caused significantly higher mortality (26.33–57.33%) than glyphosate (0.67–15%) or MCPA (2.33–19%) alone. These results confirm the synergistic effect of the glyphosate + MCPA combination on the mortality in these nematodes. Nematode infectivity of Galleria mellonella larvae in response to the herbicides presence was evaluated in Petri dish assays containing sterile sand. Nematode infectivity was not significantly reduced by exposure to herbicides in S. feltiae but H. bacteriophora was less tolerant. Synergistic effect was obtained in the nematode mortality test but no synergistic effect was observed in the nematode infectivity assay. Our results suggest that possible synergistic effects of agrochemicals on survival of nematodes should be tested before mixing with entomopathogenic nematodes.     

Evaluation of the nematodes Steinernema feltiae and Thripinema nicklewoodi as biological control agents of western flower thrips Frankliniella occidentalis infesting chrysanthemum

In greenhouse studies, we evaluated a commercial formulation of the entomopathogenic nematode Steinernema feltiae and the inoculative release of the thrips-parasitic nematode Thripinema nicklewoodi against western flower thrips (WFT), Frankliniella occidentalis Pergande infesting potted chrysanthemums. Foliar sprays of S. feltiae applied at 1.25-2.5×10³ IJ mL^-1 and 1000 - 2000 L ha^-1 at 3-day intervals alone (targeting feeding stages) or in combination with soil applications (simultaneously treating non-feeding stages in the soil at the same rates) decreased but did not provide adequate control of thrips in flowering plants artificially infested with a dense population. Similar nematode treatments applied for four to five applications at 6-day intervals in two batches of initially clean chrysanthemums failed to prevent unacceptable damage to flowers and leaves from a dense natural infestation within the greenhouse. Although some IJ survived up to 48 h within flowers and flower buds, few nematode-infected thrips (larvae and adults) were recovered. In studies with T. nicklewoodi (which is not amenable for mass production), the inoculative releases of two parasitized hosts per plant enabled the nematode to become established within existing WFT populations under greenhouse conditions. However, relatively poor transmission and slow speed of kill (nematode primarily suppresses populations through host sterilization) prevented low level inoculations being effective over a single crop cycle. Further studies showed that transmission of T. nicklewoodi persisted for nine host generations, infected up to 83% of adult thrips and provided long-term suppression of discrete caged populations, but only after uneconomically high thrips densities had been reached.     

Differential susceptibility of subterranean termite castes to entomopathogenic nematodes

We examined the attachment and infectivity of two entomopathogenic nematode species, Steinernema carpocapsae and Heterorhabditis indica, on soldiers and workers in two subterranean termite species, Coptotermes formosanus and C. vastator. In attachment tests with S. carpocapsae, more nematodes attached to soldiers of C. formosanus and C. vastator in the absence of workers compared to soldiers that were in the presence of workers. In tests with soldiers alone, workers alone, and mixture of equal numbers of workers and soldiers, soldiers in the mixed groups had lower mortality than soldiers alone after 1 and 4 days for both termite species. Exposure of small groups of either termite species to S. carpocapsae resulted in higher mortality of soldiers after 1 and 4 days post exposure. Mortality in soldiers alone exposed to H. indica was not significant compared to mortality in mixed groups at 1 day exposure, but was significant after 4 days. In concentration-mortality tests, a significant two-way interaction existed between nematode concentration and termite caste for C. formosanus exposed to S. carpocapsae for 1 and 4 days. A significant effect of nematode concentration was found for C. vastator exposed to H. indica for 1 day. This termite species had lower mortality when exposed to H. indica after 1 and 4 days compared to C. formosanus. At 4 days post exposure to H. indica, the effects of nematode concentration and termite caste were significant. Steinernema carpocapsae caused higher mortality than H. indica, but mortality of workers was higher when exposed to H. indica. Soldiers of both species experienced rapid mortality when exposed to S. carpocapsae, whereas soldiers of C. vastator experienced lower mortality when exposed to H. indica. Thus, our results show that when soldiers alone or workers alone are exposed to the nematodes, there is a differential susceptibility of soldiers and workers to nematode infection with soldiers being more susceptible than workers. In a mixed group of soldiers and workers or workers alone, it appears that grooming behavior of the workers serves as a mechanism to reduce nematode infection of soldiers and workers. The reason for this differential response to nematode infection is that soldiers do not exhibit grooming behavior.     

Extraction of polyhydroxyalkanoate from Sinorhizobium meliloti cells using Microbispora sp. culture and its enzymes

Sinorhizobium meliloti produced 50% polyhydroxyalkanoate (PHA) in the biomass in the presence of sucrose as carbon substrate. Isolation of the intracellular PHA was achieved through a secondary fermentation involving a cell lytic actinomycetes species namely Microbispora sp. without further supplementation of nutrients to the S. meliloti fermented broth, at 30 °C, 150 rpm up to 72 h. Microbispora sp. cells that showed pelleted growth was removed by filtration and the released polymer contained in the filtrate was extracted by chloroform or an admixture of Triton X 100 (0.6%) a surfactant and ethylene diamine tetra acetic acid (EDTA) a chelating agent. Yield of PHA obtained was 49, 41 and 7% of biomass weight after 24, 48 and 72 h of lytic culture fermentation, respectively. Corresponding recovery of the polymer was 94, 82 and 15% of 90% purity. Alternatively Microbispora sp. lytic enzyme was obtained by its cultivation in nutrient broth with S. meliloti cells as substrate and the supernatant was used for the hydrolysis of the PHA containing biomass to release PHA. A620 lytic activity value for the broth was 200 at 72 h. The enzyme showed optimized activity at 50 °C, pH 7 and this was used to hydrolyze 5 g/l of thermally inactivated biomass of S. meliloti to recover 94% of total PHA present in the cells and the polymer produced was 92% pure. Decreased cell lytic activity in the presence of soluble protein added in the form of bovine serum albumin indicated that the hydrolytic activity may be due to proteases. The polymer was characterized by GC, NMR and DSC and was found to be polyhydroxybutyrate-co-hydroxyvalerate (97:3 mol%) with a melt temperature of 169 °C.     

Implication of Papio anubis in the transmission of intestinal schistosomiasis in three new foci in Kime area, Ethiopia.

Epidemiological studies were conducted in the Lake Langano area in the Rift Valley of Ethiopia to determine the occurrence of schistosomiasis and assess factors involved in its transmission. Microscopic examination of faecal specimens from free ranging Papio anubis (anubis baboon) troops from Bishan Gari and Burka Dita forest reserves revealed Schistosoma mansoni eggs with a prevalence of 12.1% (11/91) and 26.2%(34/130), respectively. The eggs were viable as confirmed by miracidial hatching and infectivity tests. Out of the total 12 communities (three schools, five villages and one herdsmen community) surveyed for schistosomiasis around Lake Langano, individuals excreting S. mansoni eggs were found in nine communities with prevalence of infection ranging from 1.4 to 43%. The intensity of infection ranged from 24 EPG (eggs per gram of faeces) to 243 EPG. Excretion of viable eggs by the baboons indicate that they play a role in maintenance of S. mansoni infection in the locality. The detection of S. mansoni eggs in young children, collection of cercarial-infected Biomphalaria pfeifferi in water bodies, and establishment of S. mansoni infection in lab-bred mice have confirmed establishment of transmission foci in Kime area, south-east of Lake Langano. However, the lake itself does not seem to support transmission of schistosomiasis since no snails were found along the shore of the Lake. Further investigations are indicated to fully elucidate the role baboons play in the epidemiology of schistosomiasis in the Rift Valley of Ethiopia. The risk of introduction of water-based development projects in these new endemic foci in relation to S. mansoni infection in the baboons is discussed.     

Pesticide Susceptibility of Two Coccinellids (Stethorus punctum picipes and Harmonia axyridis) Important in Biological Control of Mites and Aphids in Washington Hops

The susceptibility of Stethorus punctum picipes (Casey) and Harmonia axyridis Pallas larvae to pesticides used or with potential for use in Washington hops, was examined in laboratory bioassays. All pesticides tested except the miticide, hexythiazox, the insecticides, chlorpyrifos and pirimicarb, and the fungicide, mycobutanil, produced 100% mortality in S. punctum picipes at concentrations equivalent to field rates. The insecticides, pirimicarb, endosulfan, and thiamethoxam were least toxic to H. axyridis. Bifenthrin, diazinon, dimethoate, methomyl, carbaryl, malathion, phosmet, imidacloprid, and chlorpyrifos were highly toxic. The miticides, abamectin and fenpyroximate were highly toxic, milbemectin was moderately toxic but all other miticides tested were non-toxic. All fungicides had low toxicity. Selection and use of pesticides compatible with natural enemies and conservation biological control in Washington hop production is discussed.     

Biocontrol of Acanthoscelides obtectus and Sitophilus oryzae with diatomaceous earth and Beauveria bassiana on stored grains

Combined treatment with Beauveria bassiana, and diatomaceous earth (DE) was evaluated against the bean weevil Acanthoscelides obtectus and rice weevil Sitophilus oryzae. DE from Argentina was screened both alone or in combination with water or dry fungal formulations. DE killed 100% of A. obtectus and 68% of S. oryzae showing a significantly higher insecticidal effect than the fungal dust. For A. obtectus, median lethal time (MLT) with the DE-dry fungus was significantly lower than with a fungal aqueous-suspension. In S. oryzae, powder formulations with either of B. bassiana or DE showed a MLT significantly higher than the wet treatments.     

珍稀濒危植物细果秤锤树开花生物学特性和繁育系统

为了解珍稀濒危植物细果秤锤树（Sinojackia microcarpa）开花特征和有性繁殖,对其花部形态特征、开花动态、花粉胚珠比（P/O）、柱头可授性、花粉活力、套袋试验、访花昆虫及访花频率进行观测。结果表明：（1）细果秤锤树的杂交指数（OCI）为4,单花期5~7 d,种群花期可持续20 d左右。花粉与胚珠比为4 093.21±498.56。开花后第3天的花粉活力最高（76.21%）,而开花后第7天时花粉活力较低（18.37%）。细果秤锤树柱头最适可授期在开花后第2天。（2）套袋试验表明,细果秤锤树存在部分自交不亲和性,同时不存在无融合生殖,传粉昆虫是其完成生殖过程所必需的,且异株授粉能够提高其坐果率和结籽率。细果秤锤树的访花昆虫有3目5科7种,主要访花昆虫有黄胸木蜂（Xylocopa appendiculata）、熊蜂（Bombus sp.）、胡蜂（Vespa sp.）、中华蜜蜂（Apis cerana）、黑带食蚜蝇（Episyrphus balteatus）、其中熊蜂平均访花频率最高,达（8.67±0.21） 次·h^-1。对该物种开花生物学特征与繁育系统进行深入研究,有利于进一步探究其濒危机制,为后续珍稀濒危植物的研究提供理论依据和参考。     

Pathogenicity of Heterorhabditis bacteriophora, Steinernema glaseri, and S. scarabaei (Rhabditida: Heterorhabditidae, Steinernematidae) Against 12 White Grub Species (Coleoptera: Scarabaeidae)

We compared the pathogenicity of the entomopathogenic nematodes Heterorhabditis bacteriophora, Steinernema glaseri, and S. scarabaei against third instars of 12 white grub species. The Japanese beetle (Popillia japonica) was highly susceptible to all nematode species. Oriental beetle [Exomala (=Anomala) orientalis], European chafer (Rhizotrogus majalis), Asiatic garden beetle (Maladera castanea), and the May/June beetles Phyllophaga crinita, Ph. congrua, and Ph. (Subgenus Phytalus) georgiana were highly susceptible to S. scarabaei but had mediocre to low susceptibility to H. bacteriophora and S. glaseri. The black turfgrass ataenius (Ataenius spretulus) was very susceptible to H. bacteriophora but had mediocre susceptibility to S. glaseri and S. scarabaei. Northern (Cyclocephala borealis) and southern masked chafer (C. lurida) had mediocre and southwestern masked chafer (C. pasadenae) and green June beetle (Cotinis nitida) had low susceptibility to all nematode species.     

Assessment of the antibacterial activity of selected flavonoids and consideration of discrepancies between previous reports

Activity of the flavonoids apigenin, baicalin and galangin against sensitive and antibiotic resistant strains of Staphylococcus aureus, Enterococcus faecalis, E. faecium, Escherichia coli and Pseudomonas aeruginosa was investigated. Using an agar dilution assay, galangin was shown to have a minimum inhibitory concentration (MIC) of 25 to 50 μg/mL against all six strains of S. aureus but negligible activity against the other species. Apigenin displayed only marginal activity against S. aureus and no activity was detected from baicalin. In inhibition curve studies, galangin caused a 100,000-fold decrease in the viability of a growing population of S. aureus NCTC 6571 within the first two hours of treatment. Decreases in viability of S. aureus NCTC 11561 and NCIMB 9968 populations were also observed.