Alternative Bekämpfungsstrategien gegen die Kleine Weiße Rosenschildlaus Aulacaspis rosae (Bouché) (Hemiptera: Diaspididae) an Schnittrosen unter Glas mittels dem Einsatz von Leinöl

The rose scale Aulacaspis rosae has proven to be extremely difficult to control. For some years Hamburg flower producers have reported an increase in infestations in greenhouse grown rose crops. So far no pest management program, including natural, mechanical and chemical methods, have provided effective control. The rose scale feeds on parenchyma plant sap and is mainly found on the woody parts of roses. Under greenhouse conditions several generations may appear in a single year. Contact insecticides do not penetrate the protective covering of the scale insects and are most effective when applied on young larvae stages which are not protected by the shield-like cover yet. However due to long hatching periods the occurance of larvae overlaps with the hatching of the following generation. The outcome of this is a continuous presence of newly emerged larvae on the plants. Resulting in that pesticides need to be frequently applied which is both time consuming and impractical for the gardeners. Another problem is the limited coverage of the infested plant parts when pesticides get sprayed. The scale insects are well protected by both the leafage of the roses and also they tend to crowd together and stack in layers making it harder for contact pesticides to be effective. Systemic insecticides may be effective only on those scales infesting the leaves or those that are actively producing honeydew and showed no sufficient efficacy in practical usage against the rose scale. By searching for an adequate pest management method, linseed oil was tested as an alternative application agent. Linseed oil is a drying oil and polymerizes into a solid form by reacting with oxygen in air. Treatments on permanent rose crops infested by rose scales could decrease the occurance of larvae in a knock-down effect. Newly emerged larvae could be kept sustainably on a low infestation level. The results are showing a promising pest control with good efficacy.     

Auswirkungen von Weiden (Salix spp.) und Pappeln (Populus spp.) im Kurzumtrieb auf die biologische Vielfalt am Beispiel von Laufk?fern (Carabidae)

The increasing cultivation of energy crops in the last few years may have an impact on changes in the environment, biodiversity and the landscape. Due to a longer rest of soil and reduced application of pesticides, perennial crops such as short rotation coppice (SRC) offer benefits that can have a positive effect on the biodiversity. However, to assess the overall impact of SRC on biodiversity, information on the quality of SRC as a habitat for animals and plants, depending on the woody species over several years and the management is required. In the years 2010 and 2011, the diversity of ground beetles of willow and poplar in SRC were examined using pitfall traps at three sites in southwestern Germany. It was distinguished between species, variety and age of the SRC. At all sites ground beetle diversity was significantly higher in the studied poplar stands than in those of the willows. In addition, significant differences between the varieties could be observed depending on the location and the year of examination. The older stands of the SRC showed in general a higher level of diversity. Due to the different variety preference of ground beetles it is recommended to plant a mixture of varieties. Furthermore, SRC of different ages should be established side by side, as with increasing tree age species of the open area decrease and forest species settle. Overall, SRC offer the potential to increase biodiversity in natural landscapes.     

Untersuchungen zur überlebensf?higkeit und Entwicklung der Larven zweier Herkünfte des Schwammspinners Lymantria dispar L. (Lep.: Lymantriidae) in Abh?ngigkeit von der Fra?pflanze

The polyphagous gypsy moth (Lymantria dispar) is able to feed on about 400 different woody plant species. In general, oak species are preferred – on the other hand some other groups of plants are avoided on account of the presence of toxic substances. These unfavoured hosts are, for example, most of the Papilionaceae, like locust (Robinia pseudoacacia). We compared survival rate and development of two populations of different origin with long-term habituation to oak and locust, respectively. Larvae from the population habituated to oak proved unable to develop on locust food. There must be a lack of detoxification systems to modify the toxic alcaloids and flavenoids produced by Robinia pseudoacacia. On the other hand, larvae isolated from an locust stand were able to feed on oak leaves without problems in larval development or eclosion of adults. Gypsy moth larvae specialized on locust as host showed increased mortality (up to 27%) in the early larval instars, but the surviving animals, especially female individuals, reached significantly higher pupal weights and showed better fecundity: 40% higher egg numbers/egg mass compared to those feeding on oak. These results indicate that the gypsy moth population originating from the locust forest had achieved a high level of metabolic adaptation to this host plant and formed a 'biotype' of Lymantria dispar with optimal reproductive conditions in this special habitat.     

Untersuchungen zur überlebensf?higkeit und Entwicklung der Larven zweier Herkünfte des Schwammspinners Lymantria dispar L. (Lep.: Lymantriidae) in Abh?ngigkeit von der Fra?pflanze

The polyphagous gypsy moth (Lymantria dispar) is able to feed on about 400 different woody plant species. In general, oak species are preferred – on the other hand some other groups of plants are avoided on account of the presence of toxic substances. These unfavoured hosts are, for example, most of the Papilionaceae, like locust (Robinia pseudoacacia). We compared survival rate and development of two populations of different origin with long-term habituation to oak and locust, respectively. Larvae from the population habituated to oak proved unable to develop on locust food. There must be a lack of detoxification systems to modify the toxic alcaloids and flavenoids produced by Robinia pseudoacacia. On the other hand, larvae isolated from an locust stand were able to feed on oak leaves without problems in larval development or eclosion of adults. Gypsy moth larvae specialized on locust as host showed increased mortality (up to 27%) in the early larval instars, but the surviving animals, especially female individuals, reached significantly higher pupal weights and showed better fecundity: 40% higher egg numbers/egg mass compared to those feeding on oak. These results indicate that the gypsy moth population originating from the locust forest had achieved a high level of metabolic adaptation to this host plant and formed a 'biotype' of Lymantria dispar with optimal reproductive conditions in this special habitat.     

Untersuchungen zum Voltinismus der Rotgelben Kiefern-BuschhornblattwespeNeodiprion sertifer (Geoffroy) in Südtirol und Trentino (Hym., Diprionidae)

Zusammenfassung  Bei einem Massenauftreten vonN. sertifer in Brentonico (am Monte Baldo im Trentino, N-Italien), in 1400–1600 m Seeh?he, wurden 1996 und 1997 Untersuchungen über den Voltinismus dieser Kurztags-Diprionide durchgeführt, durch Aufzucht von über 2000 Kokons (Abb. 1; Tab. 1–4). Dazu waren L4–5 Larven vonN. sertifer aus den verschiedenen H?henlagen nach Denno (430 m) und nach Brixen (550 m) transferiert und dort unter Freilandbedingungen aufgezogen worden. Die Untersuchungen wurden erg?nzt durch Populationsbeobachtungen aus Südtirol von St. Ulrich Gr?den (1200 m) sowie mittelitalienischen Herkünften aus Riolo Terme (150 m) in Brixen (Abb. 2). Diese vergleichenden Untersuchungen ergaben bei allen Populationen einen korrelativen Zusammenhang zwischen dem Zeitpunkt der Kokonbildung und dem Schlüpfen der Blattwespen. Es zeichnete sich dabei das Grundprinzip ab: je sp?ter die Kokonbildung—desto früher erfolgt das Schlüpfen der Blattwespen. Frühe Einspinner (z. B. Mai/Juni) schlüpften erst sp?t im Oktober, hingegen sp?te Einspinner (z. B. Anfang Aug.) bereits ab Ende August. Bei sp?ter Kokonbildung reduziert sich somit die obligatorische sommerliche Kokondiapause, bis sie schlie?lich bei Kurztagsbeginn (mit 15 Stunden Helligkeitsphase), Anfang August, zur Subitanentwicklung führt. Durch diese unterschiedlichen Kokonbildungszeiten kommt es auch beiN. sertifer —?hnlich wie bei anderen Diprioniden—zu verschiedenen Schlüpfwellen W1–W4, die auch aus den Pheromonfallenf?ngen ersichtlich sind (Abb. 2: 3); die m?glichen variablen Kombinationen dieser Schlüpfwellen werden diskutiert. Es wird aufgezeigt, da? der Voltinismus und das überliegerverhalten vonN. sertifer ma?geblich durch die Photoperiode und korrelierte klimatische Faktoren bestimmt werden. Die festgestellte niedrige überliegerrate von nur 1–2% h?ngt mit der südlichen und w?rmeren Lage des Befallsgebietes Brentonico (45° 49’ N) zusammen. Dabei spielt auch die au?ergew?hnliche Langlebigkeit der Imagines, die einige Wochen betragen kann, eine wichtige Rolle.

---

During an outbreak ofN. sertifer in Brentonico (on Monte Baldo, Trentino, North Italy), in altitudes of 1,400–1,600 m, surveys were made in 1996 and 1997 on the voltinism of these short-day-Diprionide, wherely over 2,000 cocoons were reared (fig. 1; tab. 1–4). Therefore L4–5 larvae ofN. sertifer from different altitudes were transferred to Denno (430 m) and to Brixen (550 m) and were reared there under outdoor conditions. These surveys were completed with further observations of populations from South Tyrol, of St. Ulrich Val Gardena (1,200 m) and italian provenances from Riolo Terme (150 m) in Brixen (fig. 2). These comparative studies revealed a correlative connection between the time of cocoonspinning and adult emergence. They showed the following principle: the later the cocoonspinning, the earlier the adult emergence. Early spinners (e. g., May/June) emerge only late in October, while late spinners (e. g., early August) emerge as soon at the end of August. In the case of late cocoon spinning the obligatory summer cocoon diapause is so reducted, eventually—at the start of the short-day phase (with only 15 hours brightness), in early August—leading to a subitan development. These different cocoon spinning periods cause varying flywaves, W1–W4, ofN. sertifer, similarly to other Diprionidae; this seems evident also by pheromon-trap catches (fig. 2: 3). The possible variable combinations of these fly-waves are discussed. It is shown that voltinism and diapause behaviour ofN. sertifer are essentially conditioned by the photoperiod and correlated climatic factors. The determined low diapause rate, of just 1–2%, is connected with the southern and warmer location of the outbreak area of Brentonico (45° 45’ N). The exceptional longevity of adults, which can amount to several weeks, also plays an important role.

     

Eignung verschiedener Anbaumedien f??r den erdelosen Subsistenzanbau in Iquitos (Peru) und deren Wirkung auf Wachstum und Qualit?t von Pfl??cksalat (Lactuca sativa L. var. crispa L.)

Peruvian nutritional indicators demonstrate, in particular for the underprivileged groups in remote regions, as in Iquitos, a malnutrition caused by the insufficient uptake of vitamins and mineral nutrients. Promoting cultivation and consumption of vegetables shall counteract this situation, but unfavourable tropical conditions complicate local crop growing in Iquitos. Due to transportation by air, in Iquitos imported vegetables are expensive goods and thereby prohibitive for many people. Soilless cultivation techniques represent an opportunity to cultivate high-value crops throughout the year on a regional basis. By the use of simplified methods, this technique also offers the underprivileged population the means to provide themselves with healthy vegetables. In the present study, regional available cultivation media were tested for simplified soilless cultivation in Iquitos. The characteristics of one substrate-less cultivation method based on a nutrient solution and eight different types of substrates, derived from the base substrates rice husks, gravel, sand and composted saw dust were compared. Using the example of Lactuca sativa L. var. crispa L. ??Grand Rapids??, general and physico-chemical characteristics of the nine cultivation media and their influence on crop developing and crop quality were determined. Results show that rice husks also gravel-sand-mix 2:1 and 1:2 are particularly suitable for soilless cultivation of loose leaf lettuce in Iquitos. Using these substrates, lettuce showed the best growth of shoots and roots and the highest yield. The crop quality was high for all tested cultivation media. If high weight and cost of the mineral substrate is not assessed negatively, it could also be used for plant breeding. It is to be assumed that a combination of rice husks and gravel-sand-mix is advantageous, since an optimised substrate weight and an improved water-air balance are to be expected.