First Report of Diaporthe gulyae Causing Phomopsis Stem Canker of Sunflower (Helianthus annuus) in Argentina

Between 2014 and 2017, elongated, brown lesions were observed on the stem and heads of sunflower (Helianthus annuus L.) plants in the Argentine Southern Sunflower Region (ASSR). A total of 66 diseased plants (40 stems and 26 heads) were sampled from the three production fields: Balcarce (37°52′36.6″S; 58°15′29.4″W; 19 samples), Orense (38°41′36.3″S; 59°47′01.9″W; 36 samples), and Pieres (38°23′31.2″S; 58°40′22.8″W; 11 samples). Fungal isolations were made from the lesion margins of the stem and head by cutting, surface disinfesting, and plating tissue pieces on potato dextrose agar (PDA) amended with 0.02% lactic acid (pH 4.5). The PDA plates were incubated at 25°C for 7 to 10 days under a 12-h photoperiod, and hyphal tips of white to gray colonies were transferred to fresh PDA plates

Six species of Diaporthe associated with Phomopsis stem canker of sunflower in southern Pampean region of Argentina

A survey of 67 commercial fields in 19 locations was conducted in the southern Pampean region of Argentina for Phomopsis stem canker of sunflower (Helianthus annuus L.) between 2014 and 2019. A total of 210 plants having typical symptoms of Phomopsis stem canker were randomly sampled, and fungal isolation was performed. Of the 187 isolates of Diaporthe that were recovered, 94% of the isolates showed morphological characteristics similar to D. helianthi, 3% to D. gulyae, 1% to D. caulivora, 1% to D. sojae, 0.5% to D. kongii, and 0.5% to D. longicolla. Following morphological characterization, the identity of the six morpho-species was confirmed by phylogenetic analyses of b-tubulin, translation elongation factor 1-a, and internal transcribed spacer gene regions. Koch’s postulates were completed for the six fungi by inoculating one susceptible sunflower hybrid with one isolate each of the six species of Diaporthe using the stem-wound inoculation method. Seven days postinoculation, significant differences in disease severity were observed between the six isolates (P < 0.0001), with D. helianthi and D. gulyae isolates causing significantly greater disease severity. To our knowledge, this is the first report of D. kongii, D. longicolla, D. caulivora, and D. sojae associated with Phomopsis stem canker of sunflower in Argentina.Fil: Zambelli, Andres Daniel. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata; ArgentinaFil: Mancebo, María F.. Advanta Semillas S.A.I.C.; ArgentinaFil: Bazzalo, María E.. Advanta Semillas S.A.I.C.; ArgentinaFil: Reid, Roberto J.. Advanta Semillas S.A.I.C.; ArgentinaFil: Sanchez, María C.. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias; ArgentinaFil: Kontz, Brian J.. South Dakota State University; Estados UnidosFil: Mathew, Febina M.. South Dakota State University; Estados Unido

First Report of Alternaria Black Spot caused by Alternaria alternata on Brassica carinata in South Dakota

During July 2016, Brassica carinata planted in experimental plots near Brookings, SD (44°18′37″ N, 96°40′25″ W), were observed with black spots (∼2 mm diameter) on the leaves and stems (average disease incidence ∼40%). Leaves and stems of five diseased plants were cut into 5 mm pieces, surface-sterilized, and plated onto potato dextrose agar (PDA). The PDA plates were incubated for 5 days at 25°C in the dark

IMPEDANCE SHAPING FOR IMPROVED FEEL IN HYDRAULIC SYSTEMS

ABSTRACT Applying haptic control to mobile hydraulic equipment presents a practical yet challenging application. One criticism of newer electro-hydraulic system is a lack of &quot;feel.&quot; To a haptics researcher this sounds like a call for haptic feedback in the human-machine interface. However, for an operator the &quot;feel&quot; of the system likely has more to do with how the actual system responds to forces or higher work port pressures. At some point, the high pressures slow down the system or naturally redirect flow to lower pressure circuits in a hydro-mechanical system. How this is done plays a large part in the &quot;feel&quot; of the system. In this paper, a paradigm is presented that tries to merge these two concepts of &quot;feel.&quot; Instead of trying to make the system transparent, the goal is to make the system react to forces acting on the system then use haptic feedback to help alert the operator to these forces. This is done by shaping this impedance so that the system provides a response or &quot;feel&quot; that is closer to a typical excavator. A haptic interface is used to enhance the haptic feel. Performance is evaluated using data from human-in-the-loop testing INTRODUCTION The definition of haptics is of or relating to the sense of touch. Haptic control implies that the human-machine interface can be programmed to artificially supply the user with arbitrary force sensations. Typically the haptic force is used to relay information about the force acting on a remote or virtual environment. Haptic feedback means that information can be fed back to the operator in the form of force signals. In the case of backhoes/excavators, force signals can be generated by virtual fixtures Haptic devices can also enable coordinated motion control. Today almost all commercial backhoes/excavators are controlled by joystick commands from human operators that are mapped directly into the joint-space of the manipulator. Coordinated control is a subtle yet profound improvement over conventional hand controllers that work in joint space. Using joysticks that individ