Trichoderma harzianum produces nonanoic acid, an inhibitor of spore germination and mycelial growth of two cacao pathogens

An isolate of Trichoderma harzianum Rifai from an infected cacao pod produces and secretes nonanoic (pelargonic) acid into a liquid culture medium. Nonanoic acid (NA) was very inhibitory to spore germination and mycelial growth of two cacao pathogens, Crinipellis perniciosa Stahel and Moniliophthora roreri Cif. H.C. Evans. It was highly active causing 75% inhibition of spore germination in an in vitro assay at a rate as low as 0.09 μM for M. roreri and 0.92 μM for C. perniciosa. Mycelial growth was comparatively less sensitive to inhibition, but still there was a 75% reduction in growth with 0.62 μM in M. roreri and 151 μM NA in C. perniciosa. In contrast, NA did not affect Trichoderma mycelial growth or spore germination at concentrations that were inhibitory to the pathogens. 6-pentyl-α-pyrone was also produced and secreted into the medium by T. harzianum, however; it was not antagonistic to the cacao pathogens. Although a number of metabolites produced by Trichoderma spp. have been identified in the past, this is the first report of NA production and secretion by any Trichoderma. The results suggest that NA may play a role in the successful use of some Trichoderma spp. isolates in the biocontrol of fungal diseases of plants.     

Gesunde Pflanzen unter zukünftigem Klima

Predicted changes in average values of global climate variables (increased temperatures, altered precipitation patterns, increased concentrations of atmospheric CO₂) and changes in the frequency, duration, and degree of extremes (frost, heat, drought, hail, storms, floods, etc.) will affect agricultural crops, agroecosystems, and agricultural productivity. Although forecasts of regional climate changes are still imprecise, mean temperature increases in Europe are expected to be greater in the north (2.5–4.5°C) than in the south (1.5–4.5°C). Regional forecasts for precipitation changes are also very far from precise; however, problems with drought are expected to increase, especially in Mediterranean countries. Overall, shortage of water will be the predominant factor affecting plant growth. As higher temperatures are known to enhance plant development and especially the grain-filling duration of cereals, grain yield losses are possible in a warmer climate. On the other hand, elevated atmospheric CO₂ concentrations are known to stimulate photosynthesis and enhance growth and yield (“CO₂ fertilization”); concomitantly, leaf transpiration is reduced, resulting in improved water use efficiency. Total biomass and yield were enhanced by 20–30% in experiments with elevated CO₂ exposure (550–700 ppm) under more or less ideal growth conditions. Elucidating the interactions between positive and negative effects of climate change is of crucial importance for any prediction of future crop yields. The present paper is a brief summary mainly of the potential effects of elevated temperatures and atmospheric CO₂ on crop growth, quality, and yield. Also, adaptation measures, possible interactive effects of different climate variables, and interactions of climate change components with other growth variables (pathogens, air pollutants) are briefly described.     

Kohlfliegenauftreten im Raps

A new pest in oilseed rape the cabbage root fly (Delia radicum L.) has succeded to establish – at least regional –during the recent years. It is not easy to monitor the cabbage root fly. Although the usual yellow water trap works quite well, it is still difficult for the farmers to determine Delia radicum exactly. The amount of infestation can be assessed best in the middle of November by analysing the damages of the roots. In this article a classification scheme is proposed. It is also difficult to control this pest. While applications of Pyrethroids against the imagines and the use of Dimethoat against the larva mostly showed only little effect in the tests, some new dressing-substances proved better against the standard “Chinook” (Imidacloprid+beta-Cyfluthrin). To forward this research and to clarify factors, which influence the infestation, a project titled “Possibilities of defence and control of cabbage root fly in winter oilseed rape” has been started in November 2003. Eight crop-protection services at German Federal State level and the BBA are involved in this project, which is supported by UFOP.     

Development of an EU protocol for the detection and diagnosis of Potato spindle tuber pospiviroid*

The work described here formed part of the EU SMT DIAGPRO project, to develop diagnostic protocols for 18 regulated pests. The Potato spindle tuber pospiviroid (PSTVd) protocol was developed primarily for testing in vitro‐ and glasshouse‐grown potato plants for the purposes of post‐entry quarantine and the production of pathogen‐tested nuclear stock. After a performance audit of methods used by 12 laboratories in Europe and America by ring testing, four methods were chosen for multilaboratory validation. For most laboratories, the detection limits were 10–20 mg of PSTVd‐infective tissue for R‐PAGE; 0.25–0.5 mg for DIG‐probe; 0.062 mg for RT‐PCR; and 0.0155 mg for TaqMan (this was the lowest weight of infective tissue tested). Some laboratories were able to extend the detection limit to 0.0155 mg for DIG‐probe and RT‐PCR. The DIG‐probe and R‐PAGE are recommended as primary detection methods, with confirmation of viroid presence by any of the four validated detection methods. Specific diagnosis requires the viroid to be sequenced. Other methods may be used for primary detection, providing that they preferably detect all PSTVd isolates and other Pospiviroids that have the potential to infect potato, and detect viroid in at least 1/10 of the tissue weight normally tested per plant.     

Comparison of a baiting method and PCR for the detection of Phytophthora fragariae var. rubi in certified raspberry stocks*

In winter 2002/2003, a total of 136 root samples from 57 different raspberry stocks in Scotland were examined for the presence of raspberry root rot caused by the fungus‐like pathogen Phytophthora fragariae var. rubi. All stocks had been planted as propagation material entered at different grades in the Scottish certification scheme or had applied for plant passports. For detection, a modified ‘Duncan bait test’ was compared to a nested PCR method. The two tests identified the same infected stocks: PCR detected 10 positive samples from four different stocks, while the bait test picked up two additional positive samples coming from the same four stocks. The two tests had a similar level of reliability in this examination and a recommendation for one or the other depends mainly on the technical equipment and skills available in the laboratory.     

Development of comparable agro‐climatic zones for the international exchange of data on the efficacy and crop safety of plant protection products1

Data on the efficacy and crop safety of plant protection products can be used for registration purposes in other countries, provided crop growth conditions are comparable. This article identifies the main conditions which are relevant in this respect, with particular emphasis on climatic conditions. Comparison of several systems of agro‐climatic classification developed for the EPPO region, particularly the climate diagrams of Walter & Lieth, the climate classification system of Köppen & Geiger, the agro‐climatic areas of Thran & Broekhuizen and natural vegetation maps, has led to a division of the EPPO region (Europe, Mediterranean area, Middle East) into four agro‐climatic zones (Mediterranean, Maritime, North‐east, Central) within which conditions can be considered comparable.     

Long‐Term Totally Implantable Venous Access Ports in Dogs and Cats Receiving Chemotherapy

Introduction:  We evaluated the totally implantable subcutaneous vascular access port (VAP) in 16 cancer patients undergoing intermittent chemotherapy for more than 30 months.
Methods:  Ports were surgically placed (The CompanionPort, Norfolk Vet Products, Skokie, Illinois 60076) in the jugular vein of 12 dogs and 4 cats between 1/2002 and 7/2004. Body weight determined polyurethane catheter size (4, 5, 7 fr.). The polysulfone port, surrounded by titanium, was anchored to subcutaneous tissue in the dorsolateral neck and confirmed with C‐arm fluoroscopy. All blood samples were obtained via VAP. Nine anticancer agents, other medications, crystalloids/colloids, and whole blood were administered. Ports were flushed every 4–5 weeks with heparinized saline solution (100 IU/ml). Removed catheters were submitted for bacteriology.
Results:  Seven of 16 animals are still alive. VAP were used for 1.5 to more than 30 months with 4–60 injections/port. Catheter tips were visualized from the left atrium distally into the caudal vena cava. Adverse events included post‐operative subcutaneous bruising and/or hematoma (4/16), difficult aspiration (4/16), catheter malposition (1/16), positional flushing (1/16), and occlusion requiring replacement (1/16). No thrombus formation or extravasation was evident. Bacterial colonization without signs of septicemia was observed in 3/4 catheters.
Conclusions:  VAP are an effective way of achieving long‐term venous access in the dog and cat. Complications are typically minor and infrequent.     

Different biological behaviour of Waldenström macroglobulinemia in two dogs

Waldenström Macroglobulinemia is a low‐grade immunosecretory disorder associated with lymphoid tumours, which is rarely reported in veterinary medicine. In this study, we describe two clinical cases of this rare syndrome in dogs, each characterized by a different onset and clinical course. In one case, a hyperacute onset and aggressive behaviour of the neoplasm was observed. Absolute serum viscosity (SV) was retrospectively evaluated in order to explain clinical findings. Rotational viscosimetry showed good precision in measuring SV. Both dogs had SV values higher than a control groups of healthy dogs although only one subject developed hyperviscosity symptoms and complications. At high paraprotein concentrations, a slight reduction of the M‐component was associated with a marked decrease in SV. Thus, this work suggests that SV assessment is a relevant tool for managing monoclonal gammopathies, whose usefulness should be further confirmed in larger cohorts of dogs.     

The Blood-Vessel System of the Equine Periodontal Ligament: a Mesoscopic Study on Corrosion Casts

Several investigators have suggested that the blood-vessel system in the equine periodontal ligament does not only serve nutritional needs, but also specific functional needs, e.g. in terms of a shock absorbing system. In order to supplement the previous data, corrosion casts of the periodontal blood vessels were studied with special attention to the spatial arrangement and connections of the vessels. The heads of eight warm-blooded horses (age 2.5–23 years, seven female, one male), which had been killed for medical reasons, were dissected. The arteria alveolaris inferior and the a. infraorbitalis were perfused with 100 ml Heparin (20 000 IU) followed by 100 ml tap water. After storage at 4°C for 24–96 h, 10–200 ml methacrylate resin (Biodur^TM E20) were injected by use of a cartridge pistol for approx. 1 h. After polymerization for 24 h at 60°C, the jaws were frozen and cut with a steel band saw in a horizontal, sagittal or transversal plane to obtain segments that exposed the periodontal space. The specimens were macerated in detergent at 60°C until the soft tissues had vanished. Care was taken to keep the periodontal vessels complete and in topographical integrity. The vascular casts were mesoscopically examined by use of a dissection microscope (magnification 5.8×–40×). The blood vessels in the periodontal space connected with vessels in three other sites:

• (1)

  occlusal – with the blood vessels of the gingiva;