The identity of Hyla leucotaenia Burmeister, 1861 (Anura: Hylidae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Effects of UV-B radiation on the antagonistic ability of Clonostachys rosea to Botrytis cinerea on strawberry leaf disc

Human activities are altering the concentrations of ozone in the troposphere and hence in the incidence of ultraviolet-B (UV-B) on Earth’s surface. Although representing only five percent of UV-B radiation striking the Earth's surface, this radiation has the potential to cause effects on biologically active molecules. Sensitivity to UV-B radiation is one of the limitations of biological control of plant pathogens in the field. The objectives of this work were to evaluate the effects of UV-B on several isolates of Clonostachys rosea, and the ability of an isolate of C. rosea, previously selected for its tolerant to UV-B radiation, to control Botrytis cinerea on strawberry leaves in controlled conditions (strawberry leaf discs). The germination of C. rosea conidia was inversely proportional to the irradiance. The most tolerant strain (LQC62) had relative germination of about 60% after irradiation of 4.2kJ/m2, and this strain was selected to be used in the subsequent studies. The data showed that even with exposure to UV-B radiation, C. rosea LQC62 controlled the pathogen. Conidial concentrations of strain LQC62 above 105 conidia/ml showed higher tolerance to UV-B radiation and increased ability to control more than 75% of the B. cinerea even with exposure to radiation. According to our results, in addition to showing less growth under UV-B, conidia of C. rosea had lower antagonistic ability. Further studies are needed to observe the tolerance of B. cinerea conidia to UV-B radiation and thereby prove that an environment with increased UV-B radiation may be favoring the pathogen due to a lower ability of C. rosea to control the pathogen in conditions of increased UV-B.

Monteggia lesion in an Asian small-clawed otter (Aonyx cinerea).

A 10-yr-old female Asian small-clawed otter (Aonyx cinerea) presented with a history of right forelimb lameness. Antebrachial radiographs revealed a Monteggia lesion, classified by cranial radial head luxation and distal diaphyseal ulnar fracture. Open reduction with placement of an ulnar-radial positional screw was performed. The lateral collateral ligament was reconstructed using suture anchored by a condylar screw and bone tunnel in the radius. Reduction and proper implant placement was confirmed on postoperative radiographs. The ulnar-radial positional screw was removed 6 wk postoperatively to allow proper supination and pronation. Limb function was greatly improved at this time; however, a mild lameness was still observed. At 7 mo postoperatively, the otter was ambulating lameness-free. Radiographs documented proper joint reduction and stable condylar screw. At 32 mo postoperatively, the otter continued to exhibit normal ambulation.

Sur le développement du Botrytis cinerea

Par le Dr. Gy. de Istvánffi

Predator-induced stress makes the pesticide carbaryl more deadly to gray treefrog tadpoles (Hyla versicolor)

Global declines in amphibians likely have multiple causes, including widespread pesticide use. Our knowledge of pesticide effects on amphibians is largely limited to short-term (4-d) toxicity tests conducted under highly artificial conditions to determine lethal concentrations (LC50). We found that if we used slightly longer exposure times (10–16 d), low concentrations of the pesticide carbaryl (3–4% of LC504-d) killed 10–60% of gray treefrog (Hyla versicolor) tadpoles. If predatory cues also were present, the pesticide became 2–4 times more lethal, killing 60–98% of tadpoles. Thus, under more realistic conditions of increased exposure times and predatory stress, current application rates for carbaryl can potentially devastate gray treefrog populations. Further, because predator-induced stress is ubiquitous in animals and carbaryl's mode of action is common to many pesticides, these negative impacts may be widespread in nature.

De Hyla : pars I.

Thesis (doctoral)--Universitas Litterarum Viadrina.

Interindividual Differences in Leg Muscle Mass and Pyruvate Kinase Activity Correlate with Interindividual Differences in Jumping Performance of Hyla multilineata

Frog jumping is an excellent model system for examining the structural basis of interindividual variation in burst locomotor performance. Some possible factors that affect jump performance, such as total body size, hindlimb length, muscle mass, and muscle mechanical and biochemical properties, were analysed at the interindividual (intraspecies) level in the tree frog Hyla multilineata. The aim of this study was to determine which of these physiological and anatomical variables both vary between individuals and are correlated with interindividual variation in jump performance. The model produced via stepwise linear regression analysis of absolute data suggested that 62% of the interindividual variation in maximum jump distance could be explained by a combination of interindividual variation in absolute plantaris muscle mass, total hindlimb muscle mass ( excluding plantaris muscle), and pyruvate kinase activity. When body length effects were removed, multiple regression indicated that the same independent variables explained 43% of the residual interindividual variation in jump distance. This suggests that individuals with relatively large jumping muscles and high pyruvate kinase activity for their body size achieved comparatively large maximal jump distances for their body size.

Methyl jasmonate vapour treatment suppresses specking caused by Botrytis cinerea on cut Freesia hybrida L. flowers

Treatment of cut freesia var. Cote d'Azur flowers with methyl jasmonate (MeJA, 0.1 mu l MeJA l(-1)) vapour suppressed petal specking caused by Botrytis cinerea infection. MeJA efficacy was concentration and incubation temperature dependent. Disease severity, lesion numbers and lesion diameters decreased with increasing MeJA concentration from 0.025 to 0.1 mu l MeJA l(-1). However, there were no significant (P > 0.05) differences among MeJA concentrations examined. MeJA was more effective in reducing B. cinerea flower specking at 20 degrees C than at 12 degrees C. MeJA treatment was ineffective at 5 degrees C. At 20 degrees C, MeJA treatment at 0.1 mu l MeJA l(-1) reduced disease severity, lesion numbers and lesion diameters by 58, 50 and 48%, respectively, as compared to untreated controls. In a repeat experiment, disease severity, lesion numbers and lesion diameters on MeJA vapour treated flowers after 12 h of incubation were reduced by 68, 56 and 50%, respectively. MeJA did not exert direct antifungal activity in-vitro, suggesting that treatment in-vivo reduced B. cinerea-induced flower specking by induction of host defence responses. MeJA at 0.1 mu l MeJA l(-1) significantly (P < 0.05) increased vase life of cut freesia flowers and delayed senescence judged by lower wilt scores and higher fresh weights as compared to untreated controls. (c) 2005 Elsevier B.V. All rights reserved.

Effects of postharvest methyl jasmonate treatments against Botrytis cinerea on Geraldton waxflower (Chamelaucium uncinatum)

Cut Geraldton waxflower (Chamelaucium uncinatum Schauer) flowers are often infected with Botrytis cinerea. Release of infection from quiescence can cause ethylene production by invaded host tissues and result in flower abscission. Postharvest floral organ abscission is a major problem for the commercial waxflower industry. Methyl jasmonate (MeJA) occurs naturally in plant tissue and has a signalling role in eliciting induced systemic resistance against disease. MeJA treatments have been shown to suppress B. cinerea infecting cut rose flowers. The present experiments investigated the potential of exogenous MeJA treatments for B. cinerea management on harvested waxflower. MeJA treatments of 10 and 100 L liquid MeJA/L of air applied to cv. Purple Pride and 1 L MeJA/L to cv. Mullering Brook gave reductions in disease severity for uninoculated stems. However, concentrations of 100 L MeJA/L applied to Purple Pride in addition to 1 and 10 L MeJA/L applied to Mullering Brook increased the incidence of floral organ fall. Flower abscission upon treatment with MeJA may be due to induced systemic resistance-associated upregulation of ethylene biosynthesis. MeJA treatments had no direct effect on B. cinerea hyphal elongation in vitro. Collectively, these results show that while MeJA treatment may elicit defence in waxflower against Botrytis, the chemical also causes floral organ fall. Thus, exogenous MeJA treatments do not have potential for B. cinerea management on harvested waxflower.

Acibenzolar-S-methyl and methyl jasmonate treatments of glasshouse-grown freesias suppress post-harvest petal specking caused by Botrytis cinerea

Compounds that activate host plant defence responses potentially offer socio-environmentally sound alternative methods for disease control. In a series of glasshouse trials over 2 years, pre-harvest sprays with acibenzolar-S-methyl (ASM) and methyl jasmonate (MeJA) were tested for suppression of post-harvest infection of cut Freesia hybrida L. flowers by Botrytis cinerea. For the ASM treatments, variability in reducing the incidence of B. cinerea disease was observed between years freesia varieties, incubation temperatures and ASM concentrations. In the first year, the greatest reductions in lesion numbers on ASM-treated var. 'Cote d'Azur' were recorded using 2.86 mM ASM. For three different post-harvest temperature regimes, the relative reductions in lesion numbers, compared to untreated controls, were 45% at 5 degrees C, 40% at 12 degrees C and 30% at 20 degrees C, respectively. In the second year, lesion numbers were most reduced using 1.43 mM ASM to treat freesia var. 'Dukaat' flowers. Here, the relative reductions were to 44% at 5 degrees C, 26% at 12 degrees C and 51% at 20 degrees C. MeJA treatments were, in general, more consistently effective than ASM treatments in reducing lesion numbers and lesion diameters on cut freesia flowers. MeJA-treated (0.2 mM) freesia flowers (var. 'Dukaat') incubated at 20 degrees C showed relative reductions of 62%, and 45% for lesion number and lesion diameter, respectively. The differing efficacy between ASM and MeJA treatments could be attributed to their differential abilities to induce the salicylic acid (SA)-mediated vs. the jasmonic acid (JA)-mediated host defence pathways, respectively.

Postharvest infection of Freesia hybrida flowers by Botrytis cinerea

'Specking' on harvested freesia (Freesia hybrida) flowers is a problem worldwide. The disease is caused by the fungal pathogen Botrytis cinerea. This disease symptom detracts from appearance and reduces marketability of the flowers. Unlike other important cut flower crops (e.g. gerbera), the mode of infection and epidemiology of postharvest freesia flower specking caused by B. cinerea has not been reported. Epidemiological studies were carried out under simulated conditions typical of those occurring during postharvest handling of freesia flowers. Infection of freesia flowers by B. cinerea occurred when a conidium germinated, formed a germ tube(s) and penetrated epidermal cells. Fungal hyphae then colonised adjacent cells, resulting in visible lesions. Different host reactions were observed on freesia 'Cote d'Azur' petals at 20 degrees C compared to 5 degrees C. The infection process was relatively rapid at 20 degrees C, with visible lesions produced within 7 h of incubation. However, lesion expansion ceased after 24 h of incubation. Infection was slower at 5 degrees C, with visible lesions produced after 48 h of incubation. However, lesion development at 5 degrees C was continuous, with lesions expanding over 4 days. Light microscopy observations revealed increased host defence reactions during infection. These reactions involved production of phenolic compounds, probably lignin and/or callose, around infection sites. Such substances may play a role in restricting petal colonisation and lesion expansion. Disease severity and lesion numbers on freesia flowers incubated at 12 degrees C were higher, but not significantly higher (P > 0.05), than on those incubated at 20 degrees C. Disease severity and progression were differentially mediated by temperature and relative humidity (R. H.). Infection of freesia flowers was severe at 100% R. H. for all three incubation temperatures of 5, 12 and 20 degrees C. In contrast, no lesions were produced at 80 to 90% R. H. at either 5 or 20 degrees C.

Interface of the Environment and Occurrence of Botrytis cinerea in Pre-symptomatic Tomato Crops

Botrytis cinerea (Grey mould) is a necrotrophic fungus infecting over 230 plant species worldwide. It can cause major pre- and post-harvest diseases of many agronomic and horticultural crops. Botrytis cinerea causes annual economic losses of 10–100 billion US dollars worldwide and instability in the food supply (Jin and Wu, 2015). Grey mould losses, either at the farm gate or later in the food chain, could be reduced with improved knowledge of inoculum availability during production. In this paper, we report on the ability to monitor Botrytis spore concentration in glasshouse tomato production ahead of symptom development on plants. Using a light weight and portable air sampler (microtitre immunospore trap) it was possible to quantify inoculum availability within hours. Also, this study investigated the spatial aspect of the pathogen with an increase of B. cinerea concentration in bio-aerosols collected in the lower part of the glasshouse (0.5 m) and adjacent to the trained stems of the tomato plants. No obvious relationship was observed between B. cinerea concentration and the internal glasshouse environmental parameters of temperature and relative humidity. However the occurrence of higher outside wind speeds did increase the prevalence of B. cinerea conidia in the cropping environment of a vented glasshouse. Knowledge of inoculum availability at time periods when the environmental risk of pathogen infection is high should improve the targeted use and effectiveness of control inputs.