Integrated control of the fossorial form of Arvicola terrestris in orchards1

For the replacement of endrin for Arvicola terrestris control in The Netcerlands, an integrated control scheme has been developed. The scheme includes: cultivating arable crops during at least one year before planting of the trees; mole control to prevent easy access of A. terrestris; planting trees in wire netting at the edges of the orchard; early detection of damage, so that spot treatments are still feasible; only when damage is widespread, overall treatment with bromadiolone.     

Present status of fireblight in the Federal Republic of Germany1

The three phases of spread of fireblight in FRG are described, from its first appearance in 1971 to the present day. The disease is now well established in Schleswig-Holstein and Niedersachsen and scattered outbreaks have occurred over the whole of the rest of the country (but only one in Bayern). The control strategy now centres on destruction of diseased plants within 500 m of any outbreak found in an orchard or nursery (object protection).     

Plant Protection Forecasting Service in the Federal Republic of Germany1

In the Federal Republic of Germany, plant protection is a matter for the several Federal Lander. Each of the regional plant protection offices has built up a warning system of its own, although there are no essential differences between them. The warnings are based on field investigations which are mostly carried out by technicians. However, it is not possible to inspect all fields, orchards, etc., as the areas of crops are too vast. Warnings follow a general pattern: information on the situation, followed by conclusions on further development; recommendations for control measures; and, most importantly, indications of possible undesired or even dangerous side-effects and how to avoid them. The warnings are published and also distributed by telephone and radio. Warnings on sugar beet in the Nordrhein area are distributed by the sugar factories to each of the farmers concerned. The forecasting service can certainly be improved by scientific progress. On the other hand, practical improvement is indispensable. The main problem is how to get more information from the field. There is little hope that the personnel situation will change fundamentally, but every effort must be made, in view of the importance of the forecasting service. En République féderale d'allemagne, les Lander sont chargés de la protection des végétaux. Les bureaux régionaux ont développe leurs proprés systemes de prevision, mais ceux-ci sont neanmoins très semblables. Les avertissements sont basés sur des observations de plein champ qui sont réalisées pour la plupart par des techniciens. I1 n'est pas possible d'inspecter tous les champs, vergers, etc., en raison des enormes surfaces en jeu. Les avertissements reposent sur un système normalisé comprenant I'information sur la situation présente, suivie d'une évaluation de I'evolution ulterieure, dune recommandation sur les methodes de lutte, d'une indication sur les effets secondaires indesirables ou dangereux, ainsi que des moyens de les eviter. Les avertissements sont expedies sous forme de bulletins, ou communiques par telephone ou par radio. Dans la région de Nordrhein, les avertissements concernant la betterave sont distribues aux exploitants par les sucreries. Le système de prevision peut certainement btre ameliore, surtout sur le plan pratique en beneficiant des progres scientifiques qui sont realises. I1 est essentiel de mutiplier les observations de plein champ, mais il est improbable que les services responsables puissent disposer du personnel necessaire. Cependant, face à I'importance de la prévision, il faut tirer le meilleur parti des moyens disponibles.     

Outbreak of Arvicola terrestris in rice fields in Yugoslavia1

Macedonia is the southern boundary for the distribution of Arvicola terrestris (water vole) in the Balkan peninsula. Until recently, these voles were found in the region only sporadically, showing none of the cyclic population fluctuations characteristic of microtines in the continental part of Europe. An investigation was started in 1984 when the first visible signs of damage to rice in Ko?ansko Valley, caused by numbers of voles, were noted. Since then, population numbers have increased, reaching a density of 1000 individuals per ha on one locality. The causes of such an unexpected outbreak and the methods for determining role abundance are discussed. The construction of a dam and the extension of rice cultivation have reduced the natural habitats of both vole predators and their competitors. Increased pesticide and fertilizer usage have also affected the fauna unfavourably. Efficient control was attained by means of zinc phosphide baits, specially before the rice growing season (i. e. in winter and early spring).     

Potato Wart in the Federal Republic of Germany

A survey shows the present situation of the occurrence of potato wart (Synchytrium endobioticum) in the Federal Republic of Germany. By 1960 five different pathotypes (races) could be detected. Only 1 % of all foci identified after the Second World War belonged to the old pathotype 1 (← common race →). Questions of determination and emergence of new pathotypes as well as those of official restrictions on cultivar release are discussed.     

Spread of the Musk-Rat in the Federal Republic of Germany

The spread of the musk-rat in FRG is reviewed over the period since 1962. Very few areas are now free. While it has not been possible to prevent spread to the Bodensee area (lake Constance), a clear border has been established and maintained in Schleswig-Holstein. In general, it would seem that populations are more affected by habitat and weather conditions than by trapping efforts and more work is needed on the real results of the trapping programme.     

Distribution of Cereal and Grass Cyst Nematodes in the Federal Republic of Germany1

A survey of cereal and grass cyst nematodes in the Federal Republic of Germany revealed that Heterodera avenae is the most widely distributed heteroderid species and common mainly in areas with light sandy soils and intensive cereal cultivation. The so-called ≪race 3 ≫ was recovered several times, and other populations differing morphologically from ≪ typical ≫ H. avenae were found. H. hordecalis, H. bifenestra, H. mani, H. iri and Punctodera punctata were also recovered in many parts of the country. In arable soils these species constituted only 7 % of all records of cereal and grass cyst nematodes, whereas they prevailed in grassland, forests and other habitats, where they amounted to almost 80 % of the records. 93 % of all H. avenae records came from agricultural soils, but only 21 % of the records of the five other species. H. hordecalis and H. bifenestra are obviously of no economic importance in FRG.     

Computer aids to integrated control in peach orchards in Emilia-Romagna (Italy)1

An Integrated Pest Management (IPM) programme on vineyards and orchards has been applied since 1974 in Emilia-Romagna (northern Italy). The Entomology Institute of Piacenza has the scientific responsibility for peach, plum and apricot orchards. Data is collected in the field by a team of technicians with province-level co-ordination. Directions for control are given directly to farmers or through answering machines, Videotel or weekly bulletins. Data from orchards, concerning the pest and disease situaton, are processed by two Hewlett Packard 9000 computers: an HP 9845B and an HP Vectra RS/20. With the latter, data exchange is possible with MS DOS operating systems, allowing data input from a regional computer network now at the development stage.     

Ecological and Toxicological Bases of Directed Control of Arvicola terrestris (L.) and Microtus arvalis (Pallas) in Agricultural Crops 1

In order to protect crops during outbreaks of Arvicola terrestris (L.) or Microtus arvalis (Pallas), it is necessary to have formulations with acute action and high rodenticidal potential; rodenticides should be applied as baits corresponding to the hygrotrophic specialization of the species. When compared with zinc phosphide, Gliftor provides reliable control of voles in any season. The outlook of bactorodencide (bacterial preparation) applications is being determined with particular reference to their ecological effects.     

Concepts and methods in biological control of diseases in apple orchards1

The project ‘Promotion of Biological Methods in Apple Growing’ which started in Switzerland in 1985 concentrates on the control of Venturia inaequalis (scab) and Podosphaera leucotricha (powdery mildew). The project considers the selection of suitable cultivars resistant or only slightly susceptible to fungal diseases and the assessment of tolerable economic loss. It also includes curative treatments with sterol-synthesis-inhibiting fungicides, according to scab infection periods, as well as applications of plant extracts (proposed by the Institute of Biological Husbandry) and suspensions of antagonists or their culture filtrates as plant-protecting agents. Screening experiments on apple seedlings showed that root extracts of Rumex obtusifolium significantly reduced powdery mildew infections under greenhouse conditions. In field experiments treatments with R. obtusifolium extracts at intervals of 7–10 days were less effective. Saponin-containing extracts of different plants gave satisfying control of scab on seedlings in the growth chamber but were not very effective in the field. Applications of spore suspensions and culture filtrates of the phyllosphere fungi Chaetomium spp. reduced scab and mildew infections on apple seedlings to some extent. It was found that in the last 2 years even primary infections of P. leucotricha were severely parasitized by Ampelomyces quisqualis. Preliminary studies showed that the lack of efficacy of this biocontrol system is due to the delayed spread of the hyperparasite.     

Non-toxic control techniques for Microtus spp. in apple orchards1

Alternative control techniques to the use of endrin ground spray were investigated in apple orchards in Washington (US). Non-toxic control strategies using cultural practices proved highly successful in reducing high populations of Microtus montanus to low levels. Early spring raking and mowing followed by the application of herbicides to a strip along the tree line appeared to have the greatest effect. Regular mowing between the tree rows and the maintenance of bare ground under the trees prevented significant build-up of the population. Similar cultural work also substantially improved the efficacy of subsequent rodenticide applications. The economic impact of the vole damage on apple orchards, even those composed of mature trees, is substantial and the expense of intensive cultural work is justified where high vole populations are possible.     

First record of Tapesia yallundae as the teleomorph of Pseudocercosporella herpotrichoides var. acuformis, and its occurrence in the field in the Federal Republic of Germany

Tapesia yallundae is reported for the first time in the Federal Republic of Germany. Apothecia were found on wheat and rye stubble at two sites in the north of the country and one in the centre, in April 1988. Isolates of Pseudocercosporella herpotrichoides var. acuformis were obtained from germinating single ascospores, identified on the basis of colony morphology, mode of conidial production and pathogenicity to wheat and rye.     

A laboratory evaluation to determine the compatibility of microbiological control agents with the pollinator Bombus terrestris

BACKGROUND: This study was undertaken to identify any potential adverse side effects of the use of seven microbiological control agents (MCAs) on the bumblebee, Bombus terrestris L., in the context of combined use in integrated pest management (IPM). AQ10^® (Ampelomyces quisqualis), Binab‐T‐vector^® (Hypocrea parapilulifera + T. atroviride; 1/1), Prestop‐Mix^® (Gliocladium catenulatum J1446), Serenade^® (Bacillus subtilis QST713), Trianum‐P^® (Trichoderma harzianum T22), Botanigard^® (Beauveria bassiana GHA) and Granupom^® (Cydia pomonella granulovirus), comprising five biofungicides and two bioinsecticides, were investigated. Bumblebee workers were exposed under laboratory conditions to each MCA at its maximum field recommended concentration (MFRC) via three different routes of exposure: dermal contact and orally via either treated sugar water or pollen. RESULTS: The tested MCAs were found to be safe for workers of B. terrestris, with the exception of Botanigard^® and Serenade^®. Exposure to Botanigard^® via contact at its MFRC caused 92% mortality after 11 weeks, while the 1/10 MFRC killed 46% of exposed workers. For Serenade^®, topical contact and oral delivery via sugar water resulted in 88 and 100% worker mortality respectively. With lower concentrations (1/2, 1/5 and 1/10 MFRC) the toxicity decreased, but the effect depended on the route of exposure. In addition to lethal effects, nests were also evaluated for sublethal effects after treatment with the seven MCAs at their respective MFRCs over 11 weeks. In these bioassays, only Botanigard^® and Serenade^® gave rise to a significant (P < 0.05) decrease in drone production. Sublethal effects on foraging behaviour were also evaluated, and only Botanigard at its MFRC delivered via treated sugar water induced negative effects. CONCLUSION: The results demonstrated that most of the MCAs tested can be considered safe for use in combination with B. terrestris, based on the International Organisation for Biological Control of Noxious Animals and Plants (IOBC) classification. However, some can be harmful, such as the biofungicide Serenade^® and the bioinsecticide Botanigard^®. Therefore, it is recommended that all should be tested before use in combination with pollinators. In this context, it is also advisable that these MCAs should be evaluated in more realistic field situations for the assessment of potentially deleterious effects on foraging behaviour. Copyright © 2009 Society of Chemical Industry     

Effects of cultivar mixtures on scab control in apple orchards

The effects of two mixtures of resistant and susceptible apple cultivars on the development of scab caused by Venturia inequalis were observed in an experimental orchard over four years, initially for two years without fungicides against scab, and subsequently for two years with a moderate fungicide schedule. The row-by-row and within-row mixtures included a susceptible cultivar and a resistant cultivar in equal proportions. Without fungicides, the results showed a significant reduction of disease incidence over both years (7·3 to 21·3%), and severity in the second year (35·4%) in the within-row mixtures, compared to the monoculture of the susceptible cultivar. The best results were obtained when the within-row mixture was associated with moderate fungicide treatments; in this case the reduction in disease incidence reached 75·1% on leaves and 69·7% on fruits during the growth phase. The characteristics of the Venturia inaequalis / Malus  ×  domestica pathosystem and the results obtained in this experiment suggest a moderate but not negligible ability of cultivar mixtures for reducing epidemics of the disease.     

Fossorial Forms of the Water Vole,Arvicola terresths (L.), in Europe1

The species Arvicola terrestris (L.) comprises 2 main life types:an aquatic form which is more common, and a form with fossorial habits which is confined to continental Europe, from the Cantabric Cordilliera to the Carpathian Mountains. However, forms inhabiting a primary wet biotope and a secondary dry one occur in a large border zone in the north of the range of the fossorial form. The fossorial type lives underground in grassland and some types of crops. Very recently, the structure and the occupation of burrows of this subterranean rodent were studied, as well as its digging behaviour and rhythm of activity. The fossorial form of A. terrestris is very easily captured, which makes it possible to estimate its density and to follow population evolution. This microtine shows cyclic population fluctuations and, during outbreaks, causes severe damage to grassland, both by its burrowing activity and by consuming plants. In orchards, it gnaws root systems of fruit trees, mainly of apples. Damage is also serious in gardens and in horticultural crops, especially to plants with fleshy roots. This vole does not eat cereals and does not invade forests. Control methods generally used are surface treatment with organochlorine insecticides (banned in most countries), poisoning (but no efficacious toxic baits are available), fumigation of burrow systems and trapping. Taxonomic research is needed for a better understanding of the status of the different life types of A. terrestris. The biological, ecological and ethological characteristics of these forms must be defined in order to develop and test adequate control methods.