The Role of the Bark Beetle, Hylastes ater (Coleoptera: Scolytidae), as a Sapstain Fungi Vector to Pinus radiata Seedlings: A Crisis for the New Zealand Forestry Industry?

The role of the bark beetle Hylastes ater in the re-establishment of Pinus radiata forest in New Zealand is discussed. H. ater was found to be a dominant factor in seedlings mortality in the first year following planting. However, seedling mortality is usually relatively low. In contrast, it was found the large numbers of seedlings were sub-lethally damaged by H. ater feeding attempts, particularly in high risk sites. High risk sites were identified as sites that were harvested during March and April (autumn) when the peak flight activity of H. ater occurred, and subsequently planted with P. radiata seedlings the following winter. H. ater was found to vector sapstain fungi to seedlings during feeding attempts, and a strong relationship between the severity of damage and presence of sapstain fungi was identified. The role of H. ater as a vector of these fungi and the potential implications to the New Zealand forest industry are discussed.     

Induction of Systemic Resistance in Cucumber against Several Diseases by Plant Growth-promoting Fungi: lignification and Superoxide Generation

Five fungal isolates (Trichoderma, Fusarium, Penicillium, Phoma and a sterile fungus) from zoysiagrass rhizosphere that promote plant growth were tested for their ability to induce systemic resistance in cucumber plants against Colletotrichum orbiculare. Roots of cucumber plants were treated with these fungal isolates using barley grain inocula (BGI), mycelial inocula (MI) or culture filtrate (CF). Most isolate/inoculum form combinations significantly reduced the disease except BGI of Trichoderma. These fungal isolates were also evaluated for induction of systemic resistance against bacterial angular leaf spot and Fusarium wilt by treatment with BGI. Penicillium, Phoma and the sterile fungus significantly reduced the disease incidence of bacterial angular leaf spot. Phoma and sterile fungus protected plants significantly against Fusarium wilt. Roots treated with CFs of these fungal isolates induced lignification at Colletotrichum penetration points indicating the presence of an elicitor in the CFs. The elicitor activity of CFs was evaluated by the chemiluminescence assay using tobacco callus and cucumber fruit disks. The CFs of all isolates elicited conspicuous superoxide generation. The chemiluminescence activity of the CF of Penicillium was extremely high, and its intensity was almost 100-fold higher than that of other isolates. The chemiluminescence activity was not lost following treatment with protease or autoclaving or after removal of lipid. The MW 12,000 dialyzed CF fraction was highly effective in eliciting chemiluminescence activity. Chemiluminescence emission from cucumber fruit disks treated with Penicillium was the same as that obtained from tobacco callus, except that the lipid fraction also showed a high activity. Both the MW 12,000 fraction and the lipid fraction induced lignification in the epidermal tissues of cucumber hypocotyls.     

Epidemiology of a Neotropical rust (Puccinia psidii): periodical analysis of the temporal progress in a perennial host (Syzygium jambos)

The epidemiology of the Neotropical rust caused by Puccinia psidii in the Indian Myrtaceae Syzygium jambos (rose apple) was investigated in central Brazil. Disease severities recorded during a 12-month period were fitted by a Fourier curve with three cyclic components or harmonics. The first, second and third harmonics accounted for 49·6, 25·9, and 1·5% of total disease measured, respectively. A highly significant linear correlation was observed between the first harmonic and the accumulated number of days having at least 6 h wetness, or a minimum of 90% relative humidity, combined with temperatures that ranged from 18 to 20°C. No significant correlation was observed between the second and third harmonics and the weather variables evaluated. Rose apple trees showed a flush of growth with new susceptible host tissue during the evaluation period, with two major outbreaks of rust of variable intensity. Host growth was fitted by a Fourier curve with two significant harmonics. The first and second harmonics accounted for 37·5 and 22·1% of total host growth measured, respectively. A highly significant negative linear correlation was observed between the first harmonic and daily maximum and minimum temperatures, rainfall, and duration of the light period. Inoculum availability was not a limiting factor for disease progress since urediniospores were present during most of the period studied. A major peak in numbers of rust spores followed the main peak of disease severity. Thus, rust epidemics on rose apple in central Brazil were shown to depend on the duration of leaf wetness in the dark, and also on night-time temperatures during that same wetness period. This study is the first example of a periodical analysis of an epidemic in a perennial crop.     

Seasonal effects on the aerobic bacterial and fungal conjunctival flora of normal thoroughbred brood mares in Florida

Objective To evaluate seasonal effects on the presence or absence of fungal and aerobic bacterial flora of the conjunctival fornix of normal Florida Thoroughbred horses. Sample population Both eyes of 100 horses. Procedure Horses with normal anterior segment ophthalmic examinations from three farms in north central Florida were included. Each animal had the ventral conjunctival fornix of each eye swabbed with sterile culturettes. Samples were taken in October, January, April, and July (1999–2000). Aerobic and fungal cultures were plated. Bacterial cultures were reviewed at 24 and 48 h. Fungal cultures were reviewed weekly for 4 weeks. Logistic regression analysis with season as a factor and age of the horse as a covariate was performed. Statistical significance was set at P < 0.01. Results Horses ranged from 3 to 24 years of age, with a median age of 9 years. Twenty‐four genera of bacteria and 35 genera of fungi were recovered. Corynebacterium sp., Staphylococcus sp., Bacillus sp. and Moraxella sp. were the bacteria most frequently isolated. Mold species, dematiaceous mold species, Chrysosporium sp., Cladosporium sp., and Aspergillus sp. were the most frequently recovered fungi. Season did not have a significant effect on the presence of microorganisms isolated for individual horses adjusted for age. Younger horses had an increased incidence of gram‐negative rods and fungal isolates. The number of bacteria and fungi isolated are not uniform across seasons. Conclusion There were no significant differences between the number or type of organisms cultured during the sampling seasons in normal Florida horses. A large range of normal bacterial and fungal flora were isolated from these horses. The number of bacteria and fungi isolated are not uniform across seasons. The likelihood of detecting an organism depends on the horses’ age.     

Top Dressing of Feed with Desiccated Chlamydospores of Duddingtonia flagrans for Biological Control of the Pre-Parasitic Stages of Ovine Haemonchus contortus

Feeding trials were conducted with stall-fed sheep parasitized with Haemonchus contortus. For 10 days they were offered 250 g of a concentrate feed that had been top-dressed with desiccated chlamydospores of Duddingtonia flagrans at 1×10⁵, 5×10⁵, 1×10⁶ or 2×10⁶ chlamydospores/kg body weight. Pooled faeces from each group on day 7 of spore feeding were spread on different pasture plots. On day 28 after the start of spore feeding, further pooled faeces from each group were spread on the same plots. The larval burdens on the plots were monitored for 2 months and the larval harvest from in vitro faecal cultures were monitored regularly. The application of 1×10⁶ or more spores/kg body weight virtually eliminated larvae from both the pasture and the faecal cultures. The application of as few as 1×10⁵ spores/kg body weight had a profound impact on larval recovery. The effect persisted while the spores were being fed but not for more than 4 days following discontinuation of spore feeding. Top dressing supplementary feed with dried chlamydospores offers a potential way of using D. flagrans for biological control of the pre-parasitic stages of H. contortus.     

日光温室黄瓜行间温光条件观测

对日光温室越冬茬黄瓜行间温光条件的观测分析表明 ,在黄瓜行间套种食用菌是完全可行的。在保证蔬菜正常生长的同时 ,根据不同食用菌的生物学特性 ,合理搭配食用菌种类进行套种 ,可增产增收     

Efficacy of Chlorhexidine against Some Strains of Cultured and Clinically Isolated Microorganisms

The efficacy of chlorhexidine digluconate was determined against some strains of collected and clinically isolated bacteria and fungi. The efficacy was evaluated either by calculating a minimum inhibitory concentration (MIC) or by efficacy trials according to the guidelines of the European Committee for Standardization. The MIC values of chlorhexidine for Staphylococcus aureus, Microsporum gypseum, Microsporum canis and Trichophyton mentagrophytes were 0.625 g/ml, 12.5 g/ml, 50 g/ml and 6.25 g/ml, respectively. The in vitro efficacy of chlorhexidine was higher against ATCC strains of S. aureus and P. aeruginosa (0.5 mg/ml for 5 min and 0.5 mg/ml for 10 min, respectively) than against clinical isolates (0.5 mg/ml for 15 min and 1 mg/ml for 10 min, respectively). The antiseptic activity of aqueous solutions of chlorhexidine against spores of Bacillus subtilis, Bacillis sfericus and Clostridium perfringens required longer contact times than against the vegetative forms. Nevertheless, 5 mg/ml of chlorhexidine in water–ethanol 20:80 v/v was totally effective against the vegetative forms or spores of these microorganisms.     

驱除瘤胃真菌对绵羊瘤胃内纤维物质降解的影响

选取3只体况良好,带有永久性瘤胃瘘管的蒙古羊与小尾寒羊的杂交一代公羊,运用尼龙袋法研究全部驱除瘤胃真菌对绵羊瘤胃内稻草纤维物质降解的影响.结果表明：全部驱除瘤胃厌氧真菌后,改变了瘤胃内纤维物质的降解动力学参数,显著降低了瘤胃内稻草DM、NDF、ADF的降解速率（P＜0.05）,显著提高了三者的消化延滞时间（P＜0.05）,显著降低了稻草NDF、ADF的降解率,而DM的降解率有所降低,但差异不显著（P＞0.05）.说明瘤胃真菌在纤维物质降解中发挥了重要的作用.     

鸡舍真菌气溶胶潜在危害的定量评估

本文采用6级Andersen生物空气采样器和常用真菌计数培养基,在鸡舍入口处收集气溶胶真菌,经培养和纯化鉴定出78种真菌,其中包括黄曲霉、烟曲霉、黑曲霉及镰刀菌等在内的50余种真菌。研究表明鸡舍入口处空气真菌污染程度与鸡舍内没有显著差异。早晨气溶胶真菌浓度明显低于中午(P=0.07)和晚间(P=0.05)的浓度,且夏秋季节浓度相对较高,峰值在7月份。鸡舍内气溶胶真菌的年平均浓度为2.3×103 CFU/m3。黄曲霉、烟曲霉、黑曲霉在鸡舍空气中的浓度相对较高,分别超过真菌气溶胶组成平均浓度77.7 CFU/m3、63CFU/m35、7.1 CFU/m3,而镰刀菌是常见的空气真菌,其总平均浓度为74.6 CFU/m3,比平均值高出45.3 CFU/m3。平均CMD值分别为3.1μm;GSD分别为2.1。每分钟可沉积到支气管和直接侵入肺泡的活性真菌量分别是居室的3.4倍和3.3倍。本研究探讨了真菌气溶胶不同时间和季节的变化规律,并从其组成、浓度及粒子大小定量评估采样点鸡舍真菌气溶胶的危害,为有效控制禽类真菌病的流行提供科学依据和预警资料。     

Seedborne fungi detected on stored solanaceous berry seeds and their biological activities

We isolated 629 fungi from 1296 berry seeds of solanaceous plants, including tomato (Lycopersicon esculentum), eggplant (Solanum melongena), bell pepper (Capsicum annuum), and red pepper (Capsicum annuum var. annuum) preserved for long and short terms. The isolates were classified into 22 genera excluding unidentified fungi, and the fungal floras were divided into two types: the tomato–eggplant and pepper groups. The results of cluster analysis with unweighted pair-group method with arithmetic average also supported these groups. Most tomato seeds infested with Geotrichum candidum germinated and grew the same as uninfested seeds. Cladosporium sphaerospermum and Arthrinium sp. isolated from eggplant seeds strongly suppressed germination, and Penicillium variabile suppressed seminal root elongation on eggplant. Alternaria alternata, Botrytis cinerea, and Myrothecium verrucaria detected from red pepper or bell pepper seeds were pathogenic to the fruits and the seedlings after artificial inoculation.