Columnea latent viroid, originating from ornamental plants, is known to be harmful to crop plants (2). Despite the potential threat to crop plants, the importance of ornamental plants in viroid evolution is not fully appreciated. Availability of a Pospiviroid genus-specific primer pair (1) to detect the most prevalent viroids in ornamental plants and a simplified nucleic acid preparation protocol (3) for use in reverse-transcription polymerase chain reaction (RT-PCR) have facilitated surveys of ornamental plants for pospiviroids. Using the above protocol in India, leaf and shoot samples were collected randomly from roadside beds consisting of ground covers or creepers/trailing plants at the IARI campus, New Delhi. These were extracted in 50 mM NaOH + 2.5 mM EDTA solution, centrifuged to sediment the coarse debris from sap, and 10 μl of the supernatant was spotted on a nitrocellulose membrane. Individual spots were eluted with distilled sterile water (30 μl) and the eluates were used for RT-PCR detection of viroids (3). Amplified fragments or subsequently cloned plasmids were also purified using NaOH-EDTA membrane protocol. Cloning and sequencing of amplicons (195 to 224 bp) revealed a very high sequence identity with specific viroids from the viroid sequence database (NCBI). Among the 19 plant samples assayed, only three plant species were infected by viroids, although none of them exhibited any symptoms. The three plant species included: (i) moss verbena, Glandularia puchella (Verbenaceae, native to Argentina and Chile, now established in several regions of the world), infected with a viroid (Accession No. DQ846884) having 99% sequence identity to Citrus exocortis viroid (CEVd) (Accession No. S67446); (ii) trailing verbena, Verbena × hybrida (Verbenaceae, ornamental plant), doubly infected with a viroid (Accession No. DQ846885) having 95% sequence identity to CEVd (Accession No. DQ094297) and infected with another viroid (Accession No. DQ846883) having 98% sequence identity to Tomato chlorotic dwarf viroid (TCDVd) (Accession No. AF162131); and (iii) red joyweed, Alternanthera sessilis (Amaranthaceae, a perennial weed herb) infected with a viroid (Accession No. DQ846886) having 96% sequence identity to Iresine viroid (IrVd) (Accession No. DQ094293). CEVd and TCDVd were mechanically transferred to tomato seedlings causing reduced growth of plants, smaller leaves, and bunchy-top appearance of plants, symptoms similar to those typically observed with other isolates of these viroids. As expected from previous studies, IrVd was not transmitted to tomato plants. Natural infection of verbena with CEVd has been detected in North America (2) but this was a novel observation in India. Additional novel observations include: A. sessilis as a new host for IrVd; and TCDVd is the first crop viroid to be isolated from a naturally infected ornamental plant. The significance of these viroid findings in ground cover and widely grown ornamental plants may lie in their potential role in spreading the viroids to citrus plants in citrus-growing countries such as India. References: (1) H. Bostan et al. J. Virol. Methods 116:189, 2004, (2) R. P. Singh and J. A. Teixeira da Silva. Floriculture, Ornamental Plant Biotechnol. 3:531, 2006. (3) R. P. Singh et al. J. Virol. Methods 132:204, 2006.

Application of a simplified protocol for nucleic acid preparation for polymerase chain reaction (PCR) detection of greening bacterium (Candidatus Liberibacter asiaticus; Cla) and Citrus mosaic virus (CMBV) associated with citrus is described. Crude extracts of citrus tissues in NaOH -ethylenediaminetetraacetic acid solution, prepared without the use of liquid nitrogen, were spotted on a nitrocellulose membrane (NCM) and then eluted in water at 80°C for 10 min. Both the greening bacterium and CMBV were detected by PCR from the eluted liquid from the spotted NCMs. The detection efficacy for the templates obtained in the NCM-eluted liquid was comparable with that of templates obtained with a multistep laboratory method or a commercial kit for nucleic acid preparation. The protocol is simple, inexpensive, rapid, and applicable to large-scale surveys of citrus trees. The spotted-membrane methodology can also be used for short-term sample storage for future testing or for long-distance sample transport to a detection laboratory.Résumé : Un protocole simplifié de préparation d'acide nucléique pour la détection, par réaction en chaîne de la polymérase, de la bactérie causant la maladie du dragon jaune (Candidatus Liberibacter asiaticus; Cla) et du virus de la mosaïque des agrumes (CMBV) présents chez les agrumes est décrit. Des extraits bruts de tissus d'agrumes, préparés dans une solution de NaOH et d'acide éthylènediamine-tétracétique, sans utiliser d'azote liquide, ont été appliqués sur une membrane de nitrocellulose pour être ensuite élués dans l'eau par un traitement thermique à 80°C durant 10 min. Tant la bactérie responsable de la maladie du dragon jaune que le CMBV ont été détectés par réaction en chaîne de la polymérase lorsque le liquide élué de membranes a été utilisé. Les gabarits dans le liquide élué ont permis une efficacité de détection équivalente à celle obtenue avec une méthode de laboratoire comportant plusieurs étapes ou avec une trousse commerciale de préparation d'acide nucléique. Le protocole est simple, peu coûteux, rapide et utilisable pour l'examen à grande échelle des agrumes. La méthodologie d'application sur membrane peut aussi servir à l'entreposage à court terme des échantillons pour un examen subséquent ou pour leur transport sur longue distance jusqu'à un laboratoire de détection. Mots-clés : CandidatusLiberibacter asiaticus, agrumes, virus de la mosaïque des agrumes, méthode de détection, réac-tion en chaîne de la polymérase. Baranwal et al.: citrus / bacteria and virus detection / polymerase chain reaction 196

Weeds are ubiquitous and eternal pests. In India, the total annual loss of agricultural produce by weeds, insects, diseases and other pests are estimated to be 37%, 29%, 22% and 12%, respectively. Weeds are, mainly, autotrophs, but few are heterotrophs/parasitic such as Orobanche/ Phelipanche sp (Broomrape). Several species that are dominant across the world are Orobanche cernua, Orobanche crenata, Phelipanche ramosa, Phelipanche aegyptiaca, Orobanche cumana, and Phelipanche muteli. Orobanche is an important holoroot parasitic weed and cause yield losses of many economically important crops. The damage by Orobanche can range from 0-100%. Studies highlighted annual crop losses due to Orobanche infestation was to the tune of $1.3 to 2.6 billion worldwide. A Orobanche plant can produce more than 500,000 seeds, whose longevity may vary from 2-20 years. The distribution, species diversity and biology of this weed have been discussed in this review. Sound management strategies involving physical, cultural, biological and chemical options, and above all, integrated Orobanche management have been contemplated as well. New biotechnological approach that must trigger to develop host plant's resistance against Orobanche and recommended selective herbicides should be envisaged for better Orobanche management.

Conservation agriculture (CA) has emerged as a promising technology for efficient rational use of available resources and sustained productivity in the long run. By saving inputs, reducing energy usage and greenhouse gases emissions, CA-based management practices are quite viable for bringing sustenance in agricultural crop production. The CA system can provide multiple ecosystem services such as provisioning, regulating and supporting services. The regulating services include improving carbon status, and physical, chemical and biological properties of soil, which further lead to provisioning services in terms of sustained crop and water productivity. Increased soil carbon sequestration improves supporting services, namely, soil aggregation that increases available soil moisture and can be helpful for better plant growth and development. It also improves soil biodiversity both above-and below-ground. Here we focus on the potential ecosystem service benefits accrued from CA. Conservation agriculture in the long run can be a strategy for sustainable crop intensification and a climate resilient crop management system.

High incidence (up to 40%) of symptoms of yellowing and yellow mottling was observed in 5-8 years old orchards of kinnow mandarin {Citrus reticulate