Nursery Management of Two Major Below-Ground Feeding Plant Pests: Root Mealybug, Rhizoecus sp. and Rice Root Aphid, Rhopalosiphum rufiabdominalis (Sasaki) (Hemiptera: Pseudococcidae and Aphididae)

Root mealybug (Rhizoecus sp.) and rice root aphid (Rhopalosiphum rufibdominalis) are below-ground feeding insects that are difficult to control and have become major pests as production of their host plants has grown. Field trials were designed to investigate the impact new insecticides and biopesticides have on root mealybugs and rice root aphids. In our first three trials, we investigated the effects of biopesticides, entomopathogenic nematodes or fungi on reflexed stonecrop (Sedum rupestre) and stonecrop (S. montanum) against root mealybug. We found that flupyradifurone (Altus), flonicamid (Aria), chlorantraniliprole (Acelepryn), pymetrozine (Endeavor), Beauveria bassiana (Mycotrol), Chromobacterium subtsugae (Grandevo), Burkholderia spp. strain A396 (Venerate), cyantraniliprole (Mainspring) and Steinernema carpocapsae (Millenium) significantly reduced root mealybug populations compared to nontreated controls when applied as drenches in a curative manner. In our fourth trial, we evaluated biopesticides and Beauveria bassiana, on rice root aphid feeding on common rush (Juncus effusus) roots. Results showed pymetrozine significantly reduced populations as early as 14 days after treatment and continued to reduce their population throughout the remainder of the trial. However, chlorantraniliprole, cyantraniliprole, Beauveria bassiana, M-306 and MBI-203 did not significantly reduce rice root aphid populations until 28 days after initial application. Predator activity on root balls of Juncus effusus plants was also noted during the trials and may provide an integrated pest management (IPM) approach in controlling populations. Index words: reflexed stonecrop, Sedum rupestre L, stonecrop, Sedum montanum Song. & Perr, common rush, Juncus effuses L, Beauveria bassiana, Mycotrol, Steinernema carpocapsae, Millenium, reduced-risk pesticides, Chromobacterium subtsugae (Grandevo), flupyradifurone, Altus, flonicamid, Aria, chlorantraniliprole, Acelepryn, pymetrozine, Endeavor, Burkholderia spp. strain A396, Venerate, cyantraniliprole, Mainspring, M-306, MBI-203. Chemicals used in this study: flupyradifurone (Altus); flonicamid (Aria); chlorantraniliprole (Acelepryn); cyantraniliprole (Mainspring); pyrometrozine (Endeavor); Burkholderia spp. strain 396 (Venerate); Chromobacterium subtsugae (Grandevo); Beauveria bassiana (Mycotrol); AMBI-203 WDG – 30% Chromobacterium subtsugae strain PRAA4-1T cells and spent fermentation media. EPA registration number 84059-27; MBI-206 EP – 94.46% Heat-killed Burkholderia spp. strain A396 cells and spent fermentation media. EPA registration number 84059-14; MBI-203 SC2 – 98% Chromobacterium subtsugae strain PRAA4-1T cells and spent fermentation media. Experimental; MBI-306 SC1 - 94.46% non-viable Burkholderia spp. strain A396 cells and spent fermentation media. Experimental. Species used in this study: Root mealybug, Rhizoecus sp; Rice root aphid, Rhopalosiphum rufiabdominalis (Sasaki); reflexed stonecrop, Sedum rupestre; stonecrop, Sedum montanum; common rush, Juncus effusus.

Developmental, ultrastructural and cytochemical investigations of the female gametophyte in Sedum rupestre L. (Crassulaceae)

This article describes the development of female gametophyte in Sedum rupestre L. New embryological information about the processes of megasporogenesis and megagametogenesis provided in this paper expand the current knowledge about the embryology of the studied species. S. rupestre is characterized by monosporic megasporogenesis and the formation of Polygonum–type embryo sac. The process of megasporogenesis is initiated by one megaspore mother cell, resulting in the formation of a triad of cells after meiosis and cytokinesis. The functional megaspore, which is located chalazally, is a mononuclear cell present next to the megaspore in the centre of the triad. Only one of the two non-functional cells of the triad is binucleate, which occur at the micropylar pole. In this paper, we explain the functional ultrastructure of the female gametophytic cells in S. rupestre. Initially, the cytoplasm of the gametophytic cells does not differ from each other; however, during differentiation, the cells reveal different morphologies. The antipodals and the synergids gradually become organelle-rich and metabolically active. The antipodal cells participate in the absorption and transport of nutrients from the nucellar cells towards the megagametophyte. Their ultrastructure shows the presence of plasmodesmata with electron-dense material, which is characteristic of Crassulaceae, and wall ingrowths in the outer walls. The ultrastructure of synergid cells is characterized by the presence of filiform apparatus and cytoplasm with active dictyosomes, abundant profiles of endoplasmic reticulum and numerous vesicles, which agrees with their main function—the secretion of pollen tube attractants. Reported data can be used to resolve the current taxonomic problems within the genus Sedum ser. Rupestria.

The chemical composition of Sedum rupestre L. ssp. rupestre epicuticular waxes: Horticultural versus the natural plant habitat

The aim of this study was to mutually compare the chemical compositions of epicuticular waxes of two different Sedum rupestre ssp. rupestre plant material samples. These were collected during the post fructification vegetative stage from the wild-growing (NH) and cultivated populations (HH). Epicuticular waxes (isolated in the form of hexane washings of leaves and stems) were analyzed using GC-MS, GC-FID and 1D- (1H, 13C) and 2D-NMR analyses. The epicuticular wax of both samples consisted of only two alkanes and one triterpene: hentriacontane (2.9 and 4.7% in NH and HH samples, respectively), tritriacontane (31.8 and 41.3% in NH and HH samples, respectively) and germanicyl formate (61.1 and 50.5% in NH and HH samples, respectively). Based on the obtained results, it seems that the type of habitat (natural or horticultural) does not affect the qualitative but only the quantitative composition of S. rupestre ssp. rupestre epicuticular waxes.

A taxonomic study of Sedum series Rupestria (Crassulaceae) naturalized in North America

Sedum rupestre L. and its close relatives (Sedum series Rupestria) are native to Europe. Adventive populations in North America were studied both in the field and the herbaria. Our results exclude S. rupestre L. and include recognition of two additional taxa on the continent, which are distinguished with keys and illustrations: Sedum forsterianum documented as a naturalized species in the United States, from Washington, and in British Columbia, Canada and Sedum thartii, naturalized in Colorado, Maine, Ohio, Oregon, Washington and Ontario, Canada. A lectotype is established for S. forsterianum.

Comparison of Organic and Synthetic Fertilizers for Sedum Green Roof Maintenance

Fertility is an important aspect of green roof maintenance. Aesthetic quality and growth of two sedum species (Sedum album and Sedum rupestre ‘Angelina’) treated with synthetic granular fertilizer [Green View 10N-4.4P-8.3K (10-10-10)] and two organic fertilizers [Coast of Maine 4N-0.9P-1.7K (4-2-2) and Nature Safe 8N-2.2P-4.5K (8-5-5)] at 10 g N·m−2 applied as a single spring application or a split application (spring and summer) and a controlled-release fertilizer [Nutricote 14N-6.1P-11.6K (14-14-14)] at the same rate and a no fertilizer control were evaluated. The best aesthetic quality and growth was for the single application synthetic granular fertilizer, followed by the split application of synthetic granular fertilizer. Also, single applications were better than split application for the organic fertilizers, indicating that sedums use nutrients the most in spring. The organic fertilizers performed poorly because they failed to provide utilizable nutrients in adequate quantities. A low level of microbial activity in green roof media, may have contributed to the minimal amount of utilizable nutrients released by the organic fertilizers. Plants treated with controlled-release fertilizer performed similarly to the control, however, the following spring they had the best aesthetic quality, indicating the prills contained some residual nutrients.