Explore the vast range of titles available.

Mealybugs (Hemiptera: Pseudococcidae) are soft-bodied insects that infest a variety of ornamental plants, and early instars are almost undetectable to the human eye. Because the cryptic mealybugs can cause significant damage quickly, plant cuttings often are preventively dipped into pyrethroidbased insecticides. Dips differ widely, however, in their phytotoxicity, effectiveness in killing mealybugs, and operational efficiency and cost. Therefore, to assess the efficacy of alternative dips, tests were conducted on biorational products for controlling the Madeira mealybug, Phenacoccus madeirensis Green, on coleus plants, Plectranthus scutellarioides, var. ‘Big Red Judy’ L. (Lamiaceae). Initially, phytotoxicity was evaluated using different concentrations and exposure times for dips containing Natur'l oil, dish detergent, Wetcit®, or Vapor Gard®. The highest concentrations of these products for which phytotoxicity could be tolerated were 1%, 1%, 0.1%, and 0.1%, respectively, in 30 s dips. Based on the results, these concentrations were used in dips to evaluate their effectiveness in eliminating mealybugs. The most effective biorational product, Natur'l oil, then was compared with the commercial standard synthetic pyrethroid, Mavrik Aquaflow® (22.3% tau-fluvalinate). Both products killed > 90% of the nymphs within 14 d when applied as a 1% aqueous mixture for 60 s. Thus, Natur'l oil could be used instead of the pyrethroid as a dip to remove Madeira mealybugs from coleus cuttings.

Para la propagación de Solanum tuberosum, los tubérculos son la forma más empleada en la mayoría de las zonas agroecológicas. El empleo de esquejes de tallo juvenil es una práctica exclusiva de viveros y empresas agrícolas que hacen uso de hormonas enraizantes, inaccesibles para los pequeños agricultores por su alto costo. Se ha reportado que la auxina sintética 2,4-diclorofenoxiacético (2,4-D) a muy baja concentración induce al enraizamiento de esquejes y puede ser una alternativa viable para la agricultura a pequeña escala. Ante la necesidad de un mayor conocimiento, se propuso como objetivo de investigación evaluar el efecto enraizante del 2,4-D en esquejes de tallo juvenil de S. tuberosum var. yungay. La fase experimental se desarrolló en el invernadero del Instituto de la Papa y Cultivos Andinos de la Universidad Nacional de Trujillo (Perú), con plántulas procedentes del mismo instituto que se convirtieron en plantas madre donadoras de esquejes de tallo juvenil, los cuales fueron sembrados en cama de enraizamiento con diferentes concentraciones de 2,4-D. El análisis estadístico de los resultados demostró que la concentración de 0,3 % generó un promedio mayor en número de raíces (6,52), longitud de raíces (5,31 cm) y altura de plántula (2,63 cm). Se concluyó que el 2,4-D en concentración del 0,3 % produce un mejor enraizamiento de esquejes de tallo juvenil de S. tuberosum var. yungay.

Se desarrolló una metodología para el establecimiento in vitro e in vivo de Aniba perutilis Hemsl. (comino crespo), árbol colombiano en peligro crítico de extinción. En la primera etapa, se sometieron semillas de este árbol a la acción de los desinfectantes NaOCl, HgCl2 y AgNO3 para su germinación aséptica. Para inducir la formación de brotes se empleó el medio WPM y se evaluó la acción de las fitohormonas BAP, KIN, AIA, ANA y AG3 en diferentes concentraciones. Para la etapa de enraizamiento se emplearon ANA, AIB, y los medios de cultivo MS y WPM, ambos con sales reducidas a la mitad y combinados con diferentes concentraciones de AIA y ANA. En la etapa de multiplicación in vivo se emplearon plántulas establecidas en vivero para evaluar tres tamaños de explantes, categorizados según la distancia desde la base de la planta hasta el ápice: distal (11-14 cm), medio (7 - 8 cm) y basal (3 - 4 cm), con el fin de obtener plantas madres donantes de yemas axilares y mini esquejes para enraizar. En este trabajo se consolida el uso de NaOCl por 15 min como tratamiento óptimo de desinfección, produciendo un porcentaje de supervivencia superior a 60%. El medio WPM suplementado con BAP 3 mg/lt y 1.5 mg/lt de AG3 generó la producción de un promedio de 0.6 brotes/explante con longitud media de 0.82 cm; no obstante, su baja capacidad de enraizamiento permite catalogar esta especie como recalcitrante al cultivo in vitro. En condiciones in vivo, cortes a la altura media de las plantas (7 - 8 cm) promovieron la formación de 1.33 brotes/explante y 75% de enraizamiento en los mini-esquejes, constituyendo una herramienta clave en la propagación de la especie 

Trichoderma harzianum T39 and T. longibrachiatum strain 6 were applied on grapevine to determine their effectiveness against Phaeomoniella chlamydospora on vine cuttings and pruning wounds. Cuttings were dipped in a Trichoderma suspension either before or after callusing. Pre-callusing dips were carried out for 3 years and yielded contradictory results. By contrast, post-callusing Trichoderma dips led to significant growth of hairy roots and a reduction in the longitudinal discolorations caused by P. chlamydospora inoculated into the rootstock after dipping. Trichoderma spp. were also applied to pruning wounds of grafted potted vines, which were then inoculated by placing drops of a conidial suspension of P. chlamydospora on the wound surface. Trichoderma application prevented black goo and necrosis in the wood below the wound. In the vineyard, T. harzianum T39 was sprayed after pruning for two consecutive years. The biocontrol agent was re-isolated from the wood close to the sprayed pruning wounds for up to 2 months after spraying. Although further investigations are necessary, our findings suggest that Trichoderma could be one of the steps in the control of esca [Sono stati effettuati trattamenti alla vite con Trichoderma harzianum T39 e T. longibrachiatum ceppo 6 per determinarne l´efficacia nei confronti di Phaeomoniella chlamydospora su talee e ferite da potatura. Le talee sono state immerse in sospensioni di Trichoderma, sia prima, sia dopo la formazione del callo. I trattamenti prima della formazione del callo sono stati effettuati per 3 anni e hanno fornito risultati contrastanti. Al contrario, quelli successivi alla formazione del callo hanno determinato una crescita significativa delle radici pilifere e una riduzione delle necrosi longitudinali causate da P. chlamydospora inoculata nel portinnesto dopo l´immersione nella sospensione. Le specie di Trichoderma sono state anche applicate a ferite da potatura di viti innestate coltivate in vaso, che sono state successivamente sottoposte a inoculazione ponendo gocce di una sospensione di conidi di P. chlamydospora sulla superficie della ferita. Il trattamento con Trichoderma ha prevenuto lo sviluppo di gommosi nera e di necrosi nel legno al di sotto della ferita. Nel vigneto, T. harzianum T39 è stato irrorato dopo la potatura per due anni consecutivi. L´agente di controllo biologico è stato reisolato dal legno contiguo alle ferite da potatura irrorate fino a due mesi dopo il trattamento. Sebbene siano necessarie ulteriori ricerche, i nostri risultati fanno ritenere che Trichoderma può essere uno dei passaggi nel controllo del mal dell´esca.]

Dada las condiciones de competencia mundial y la importancia del sector floricultor colombiano, el análisis de ventajas cómo la mano de obra barata, los bajos costos de transporte y almacenamiento, y de desventajas cómo el nivel de distribución e identificación de la flor, problemas tecnológicos que impiden el desarrollo de nuevas especies, y las restricciones internacionales en materia social, ambiental y técnica, hacen necesario el estudio de los diferentes eslabones de la cadena de abastecimiento de este importante sector. Lo anterior se materializa mediante el análisis de la planeación, las compras, la producción y la distribución, evidenciando aspectos importantes como el cálculo y gestión de costos, la utilización de mecanismos de medición del desempeño a partir de conceptos como los costos basados en actividades ABC, y modelos de medición de la gestión de la cadena de suministro como el modelo SCOR, el modelo gSCM, y la metodología de Balanced ScoreCard.

Hot water treatment (HWT) is an effective control for endogenous pathogens, including Phaeomoniella chlamydospora, in grapevine propagating material. However, sporadic unexplained failures of HWT material do occur. In order to determine the most reliable HWT protocols, the effects of HWT at 50 deg C for 30 min, order of HWT and storage (store/HWT and HWT/store) and 3 hydration times (0, 4 and 6 h) on root and shoot development and final condition in dormant cuttings of Cabernet Sauvignon and Chardonnay were evaluated. After incubation, callus, root and shoot development were assessed. Cuttings were potted into cardboard plant bands, grown to marketable size, in a protected environment, and assessed as A grade, B grade or dead. Callus development in Chardonnay was affected by an interaction between HWT protocols and hydration times. Callus was least developed in cuttings hydrated for 15 h and stored before HWT. Callus development in all other treatments was greater (P0.05) regardless of HWT or hydration. By contrast, callus development in Cabernet Sauvignon was greater (P0.05) in HWT than in non-HWT cuttings regardless of the duration of hydration or the order of operations. Root development in Chardonnay was furthest advanced in cuttings hydrated for 15 h (regardless of HWT) and in HWT cuttings not hydrated. HWT was the only factor that affected root development in Cabernet Sauvignon. Root development was greatest in non-HWT cuttings. There were no differences between any of the treatments in either variety at final assessment. On this evidence, nurseries could apply any of the above protocols successfully. However, the benign conditions of the protected environment may have enabled the cuttings to recover from the stresses imposed by the various treatments. Had the cuttings been grown in a field nursery, there might have been differences between treatments at final assessment [Il trattamento con acqua calda (HWT) è un sistema efficace di controllo dei patogeni endogeni, compresa Phaeomoniella chlamydospora, nelle talee della vite. Tuttavia, sporadicamente si osservano insuccessi nel materiale sottoposto all'HWT. Sono stati valutati gli effetti dell'HWT, a 50 gradi C per 30 min, delle modalità di esecuzione (conservazione/HWT e HWT/conservazione) e di tre tempi di idratazione (0, 4 e 6 h) sullo sviluppo della radice e del germoglio e sulla condizione finale di talee dormienti di Cabernet Sauvignon e Chardonnay. Dopo l'incubazione, sono stati controllati il callo, la radice e il germoglio. Le talee sono state allevate in ambiente protetto e classificate come A, B o morte. Lo sviluppo del callo in Chardonnay era influenzato da un'interazione fra i protocolli dell'HWT e i tempi di idratazione. Il callo risultava sviluppato al minimo in talee idratate per 15 h e conservate prima dell'HWT. Lo sviluppo del callo in tutti gli altri trattamenti era maggiore (P0,05) nelle talee HWT rispetto a quelle non trattate indipendentemente dalla durata dell'idratazione e dalla sequenza delle operazioni. Per contro, lo sviluppo del callo in Cabernet Sauvignon era maggiore (P0,05) nelle talee HWT rispetto alle non trattate, indipendentemente dagli altri fattori. Lo sviluppo della radice nello Chardonnay era avanzato al massimo nelle talee idratate per 15 h (indipendentemente dall'HWT) e nelle non idratate. L'HWT era l'unico fattore che influenzava lo sviluppo della radice in Cabernet Sauvignon. Lo sviluppo della radice era massimo nelle talee non trattate. Non sono risultate differenze fra i trattamenti nelle due varietà. In base a questi risultati, i vivai potrebbero applicare ognuno dei protocolli indicati sopra. Tuttavia, le condizioni favorevoli possono aver consentito alle talee di riprendersi dallo stress determinato dai trattamenti. Se le talee fossero state poste in campo, probabilmente si sarebbero riscontrate differenze fra i trattamenti.]

Two methods of rooting of Zelkova softwood cuttings were analyzed: (1) quick-dip method and (2) contact method - the thin polyethylene film (20 mm) laid directly over the cuttings during the rooting process. The control for contact method was a low tunnel with a thick polyethylene film. One group of cuttings in the contact method was treated with quick-dip (IBA 2,500 microg/mL, carrier - ethyl alcohol) during 5 sec, and the other group was treated with water solution of IBA (50 microg/mL) in 24-hour treatment. The third group was control - untreated cuttings. The same groups of cuttings were also used in low tunnels. The number and length of primary and secondary roots were measured on rooted cuttings. The results of all treatments show that contact method in combination with water solution of IBA was the best with 92% of rooted cuttings. No significant differences were obtained between this treatment and quick-dip + contact method (85.3%). Rooting of cuttings under low tunnel was significantly lower. In general, contact method was better than low tunnel, disregarding the carrier used. These results recommend the almost unknown contact method in nursery propagation of Zelkova, as an alternative, non-invasive species for the conditions in Serbia.

The influence of exogenous indole-3-acetic acid (IAA) and indole-3-butyric acid (IBA) on the internal levels of these auxins was studied during the first 4 days of adventitious root formation in cuttings of Pisum sativum L. The quantitations were done by high performance liquid chromatography with spectrofluorometric detection. IBA, identified by combined gas chromatography-mass spectrometry (GC-MS), was found to naturally occur in this plant material. The root inducing ability of exogenous IBA was superior to that of IAA. The IAA level in the tissue increased considerably on the first day after application of IAA, but rapidly decreased again, returning to a level twice the control by day 3. The predominant metabolic route was conjugation with aspartic acid, as reflected by the increase in the level of indole-3-acetylaspartic acid. The IBA treatment resulted in increases in the levels of IBA, IAA, and indole-3-acetylaspartic acid. The IAA content rapidly returned to control levels, whereas the IBA level remained high throughout the experimental period. High amounts of indole-3-butyrylaspartic acid were found in the tissue after feeding with IBA. The identity of the conjugate was confirmed by 1H-nuclear magnetic resonance and GC-MS. IBA was much more stable in solution than IAA. No IAA was detected after 48 hours, whereas 70% IBA was still recovered after this time. The relatively higher root inducing ability of IBA is ascribed to the fact that its level remained elevated longer than that of IAA, even though IBA was metabolized in the tissue. Adventitious root formation is discussed on the basis of these findings

In the period 1998-2001, significant numbers of vine samples of different varieties, grafted onto different rootstocks, ready for outplanting or planted and declined a few months or years later, were collected or sent to our laboratory to investigate the presence of phytopathogenic fungi. Three hundred eighty rooted cuttings ready for outplanting, 1,250 young vines planted and exhibiting decline symptoms in the first year of establishment, 82 vines two to nine year old and 27 year old vines exhibiting the classical esca symptoms were examined. Isolations yielded the fungi Phaeomoniella chlamydospora, Fomitiporia punctata and Stereum hirsutum, as well as other fungi of the genera Phaeoacreminium, Cylindrocarpon and Botryosphaeria. The low incidence of these fungi isolated in a low percentage of samples suggested that they could not by themselves be the cause of young grapevine decline. Abiotic causes, such as lesions from improperly healed rootstock disbudding sites and graft unions made in the nursery, as well as improper storage and transportation conditions of the propagated material must also have played a role and made the decline more acute. The occurrence of the isolated fungi as endophytes and their role in the outbreak of grapevine decline remain to be investigated

Twenty healthy cuttings each were inoculated artificially with Phaeomoniella chlamydospora Phaeoacremonium inflatipes and Phaeoacremonium aleophilum. After the formation of callus, they were planted in pots. Approximately one year after inoculation, disease occurrence was recorded as the length of brown vascular streaking from the base of plant toward the shoot tip. Discolored areas were cultured on potato dextrose agar amended with tetracycline hydrochloride (PDA-tet) and pathogens were re-isolated. Inoculation with Pa. chlamydospora showed that rootstocks 3309, 420A, 110R, 5C, Schwarzmann, St. George, and Salt Creek were least susceptible, while 99R, 39-16, Freedom, Riparia Gloire, 140Ru, 16-16 and 1103 were most susceptible. When inoculated with Pm. inflatipes, 16-16,3309, AXR1, Salt Creek, 110R, 5C, Freedom and 140Ru were least susceptible, while 420A, St. George, 161-49, and Harmony were most susceptible. Inoculation with Pm. aleophilum showed that 1103, 420A, Harmony, and Salt Creek were least susceptible, while 110R, SO4, 39-16 and 161-49 were most susceptible. The susceptibility of the rootstocks and the occurrence of vine decline in the field in California did not appear to be well correlated because 3309, 101-14, 5C, and 110R were always most susceptible. But these rootstocks are the most widely planted, and hence the natural occurrence of the disease is probably skewed towards these rootstocks. However, since no resistance was detected in our study, even though there was a wide range of susceptibility, the degree of rootstock susceptibility may not be such an important factor in disease expression under natural conditions.