Microbial communities in roots of Pinus sylvestris seedlings with damping‐off symptoms in two forest nurseries as determined by ITS1/2 rDNA sequencing

A methodological molecular procedure, which included extraction and cloning of the ITS1/2 rDNA of root‐associated organisms with subsequent transformation and sequencing of representative clones, was effective for detection, discrimination and determination of the frequency of the main damping‐off pathogens in roots of Pinus sylvestris seedlings growing in different forest‐tree nursery soils and exhibiting different rates of disease progress. Roots exhibiting slower damping‐off progression were colonized by Fusarium oxysporum, Neonectria radicicola (Ascomycota) and Pythium spp. (Oomycota), which comprised 50% of the microbial community. Roots exhibiting faster damping‐off progression were dominated by Thanatephorus cucumeris (Basidiomycota), which comprised 80% of the microbial community. The microbial community was more diverse in roots with slower damping‐off progression (14 species) than in roots with faster disease progression (seven species).     

Comparative effects of cut and treated seed tubers vs untreated whole seed tubers on seed decay, Rhizoctonia stem canker, growth, and yield of Russet Burbank Potatoes

Whole seed tubers have been reported to have performance advantages over seed tubers that have been cut, even if the cut tuber pieces are treated with a fungicide dust. For this study, whole seed tubers were compared to cut seedpieces and to cut seedpieces treated with four different commercial fungicide dusts for five consecutive seasons. A new field generation 3 Russet Burbank seed lot was used for each of the five years of this study. Both whole tubers and cut seedpieces were inoculated withFusarium spp., and the seedpieces were then treated with a fungicide dust. Inoculated and uninoculated untreated controls were also included. Emergence,Fusarium seed decay,Rhizoctonia stem canker, stem numbers, and vigor, as well as yield and grade data were obtained.Rhizoctonia stem canker in stems grown from whole seed tubers was significantly higher than in stems from seedpieces receiving fungicide treatment in several of the study years. Predicting whole seed tuber performance is difficult because performance varies more from year to year than performance of cut and treated seedpieces. Yield performance of whole seed tubers was not significantly better than cut and fungicide-treated seedpieces in any experimental year, and yield of large (over 280 g) tubers was significantly less than that recorded for two of the treatments when data from all five years were combined. This study demonstrated that untreated whole seed did not outperform cut and treated seedpieces for vigor, stem numbers, disease ratings, or yield in small plot comparisons for five consecutive seasons.     

绿僵菌油剂防治新疆山地草原蝗虫的田间试验

用绿僵菌油剂在新疆山地草原对蝗虫进行了防治试验。喷药后采样,罩笼饲养从第3天开始感病死亡,第5天死亡明显增多,第6天绝大部分蝗虫死亡。该绿僵菌在自然条件下对试验区内的5种蝗虫具有相同的感染致病力。田间防效在第15天为60.9%,第18天为73.7%。     

A comparison of two intramuscular doses of xylazine–ketamine combination and tolazoline reversal in llamas

The anesthetic and cardiorespiratory effects of a low dose (LD, 0.4 mg kg^?1 xylazine and 4 mg kg^?1 ketamine) and a high dose (HD, 0.8 mg kg^?1 xylazine and 8 mg kg^?1 ketamine) of IM xylazine–ketamine combination were compared in a randomized cross‐over study using six castrated male llamas. Three llamas in each dosage group (LDT, HDT) were assigned to receive IM tolazoline (2 mg kg^?1) after 30 minutes of recumbency. All IM injections were given in the semitendinosus or semimembranosus muscles. Pulse, respiratory rate, and indirect arterial blood pressure were recorded every 10 minutes, and hemoglobin oxygen saturation was recorded every 5 minutes during lateral recumbency. Samples for arterial blood gas analysis were collected 5 minutes following recumbency and every 30 minutes thereafter. Base‐to‐apex ECG was monitored continuously. Analgesia was evaluated every 5 minutes by both a 30 minutes skin pinch and a needle prick of the toe. Most llamas breathed room air throughout anesthesia. Two llamas that developed severe hypoxemia (SpO₂ < 75%) received 5 minutes of nasal oxygen insufflation, but were maintained on room air for the rest of the anesthetic period. anova for repeated measures and Tukey's test were used to analyze cardiorespiratory data. Fischer's exact test was used to compare the ability of each to provide >30 minutes of lateral recumbency and analgesia. A p‐value < 0.05 was considered significant. Both dosages provided reasonably rapid induction following injection (LD: 10.8 ± 6.3 minutes; HD: 5.0 ± 1.1 minutes; p = 0.07). Duration of lateral recumbency and analgesia were 34.7 ± 6.7 and 27.3 ± 4.6 minutes, respectively, in the LDT llamas. None of the three remaining LD llamas remained in lateral recumbency for longer than 12 minutes. Duration of lateral recumbency and analgesia were 87.3 ± 18.5 and 67.7 ± 16.0 minutes, respectively, for the HD llamas that did not receive tolazoline. The HDT llamas were recumbent for a significantly shorter time (43.3 ± 0.6 minutes; p = 0.05). The ability to provide >30 minutes of recumbency and analgesia was better in the HD group (6/6) than in the LD group (2/6) (p = 0.03). No differences between dosages were seen in pulse rate, respiratory rate, or arterial pressures. No ECG abnormalities were seen. Transient hypoxemia was seen in the first 10 minutes of lateral recumbency in the HD group by both hemoglobin oxygen saturation (84 ± 9.5%) and by blood gas PaO₂ (44.5 ± 5.8 mm Hg). It was concluded that the HD provided more consistent results than the LD, but induced transient hypoxemia. Tolazoline shortened the recovery time in llamas receiving the HD.