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• 12

  Dec
  The impact of soil disinfection and the incorporation of crop residue into the soil on pepper yields – A long-term analysis

  Plant Protection, Vegetables

  by Shimon Pivonia, Ph.D.

  תחום או ענף אגרוטכנולוגיה; הגה"צ; ירקות

  תאריך עדכון 1/10/2011

  תיאור מלא The impact of soil disinfection and the incorporation of crop residue into the soil on pepper yields – A long-term analysis

  Shimon Pivonia, Rachel Levite, Ami Maduel - Northern and Central Arava R&D

  Email for correspondence: ShimonP@arava.co.il

  Pepper is the main crop in the central Arava and, during the 2009/10 season, this crop covered approx. 17,000 dunams in this region. In the past, growers used methyl bromide to disinfect the soil before each growing season. With the end of methyl bromide use about five years ago, growers began to use metham sodium to disinfect their soil. Since then, in most areas, no particular problems of soilborne diseases have been observed, aside from a certain increase in the level of winter collapse caused by Pythium and the appearance of the previously unknown phenomenon of plant damage caused by the free nematode Pratylenchus penetrans.
  We are conducting a long-term examination, in fixed plots, of the effects of soil-disinfection treatments on the development and yield of pepper. This study has been conducted for three years and we plan to continue it for an additional three years. Last seasom (2009/10) in the experimental area, we added a test of the effect of incorporating residue from the previous crop into the soil. Today, there is a need to find alternatives to the removal and burning of crop residues at the end of the season. The alternative of incorporating the crop residue into the soil in the field is preferable from the perspective of labor costs and for other reasons, as long as it does not negatively affect the next crop.
  This experiment was conducted at the Zohar Research Station in Sodom Valley in a greenhouse in which pepper had been grown in the past. We do not know of any soil-related problems in this plot before the start of the study. In the three years that this study has been in progress, the cultivar Celica has been used. At the end of the second season of the experiment, we did not observe any significant differences between the pepper yield of the control and the yields of the treatments that included solarization, solarization in combination with Edigan (metham sodium) and the application of Edigan through the drip-irrigation system in the absence of any solarization. Even though we did not observe significantly lower yield in the untreated control plot, the plants in that plot generally looked less good. At the end of the third year, we observed a significantly lower yield in the control treatment as compared to the three other treatments. At the end of the first year of our test of the effect of incorporating crop residue into the soil, we did not observe a difference between the treatments in which residue from the previous season was incorporated into the soil, while it was still green or after it had been killed with Adigan, and treatments in which the crop residue from the previous season was removed from the area.

  Acknowledgements
  We thank the Plant Board for helping to fund this research.

  שפה English
  מלות מפתח Capsicum, metham sodium, soil fumigant, pesticide, soil disinfestation, solarization, methyl bromide substitute, Pythium
  מחבר Shimon Pivonia, Rachel Levite, Ami Maduel
  שנה 2010
  שייכות yzvieli
  תאריך יצירה 1/10/2011
  תאריך עדכון 14/3/2012
• 12

  Dec
  Powdery mildew in Arava spring melons

  Vegetables, Plant Protection

  by Shimon Pivonia, Ph.D.

  תחום או ענף הגה"צ; ירקות

  תאריך עדכון 1/10/2011

  תיאור מלא Powdery mildew in Arava spring melons

  Shimon Pivonia, Rachel Lavite, Svetlana Dobrinin, Israel Tsabari, Ela Yosel - Central and Northern Arava Research and Development
  Yigal Elad, Dan Shtainberg - Agricultural Research Organization, Israel

  Email for correspondence: ShimonP@arava.co.il

  Melon is an important crop in the Arava. These melons are grown for export and for the local market. The use of integrated pest management and decreased amounts of chemical sprays are not yet common practice in melon production in the Arava and it is important that these areas be developed. Powdery mildew is the main foliar disease affecting melon during the spring. In order to prevent damage to the plants and crop yield, growers make multiple applications of sulfur products and other products over the course of the season. The goal of the present study was the development of an approach for managing powdery mildew that includes minimal and intelligent use of pesticides.
  During the spring seasons of 2006-2010, we conducted experiments to study the relationship between environmental conditions and the development of powdery mildew in the field and to identify a spray schedule for the control of powdery mildew. We studied the spacing of the necessary sprays, the timing of the first spray treatment and the timing of the final spray treatment in a melon cultivar that is very susceptible to powdery mildew and a cultivar with specific tolerance to powdery mildew. We also examined the possibility of controlling powdery mildew in melon through the use of systemic fungicides delivered through the drip-irrigation system. The races of powdery mildew found among melon and other cucurbits in the Arava were also defined.
  The results of these experiments indicate that the spring growing season in the central Arava (transplanting in early December and growth through the end of June in walk-in tunnels) can be divided into a number of periods defined by different phases of powdery mildew development, which are primarily dictated by temperature conditions. The first period, from transplanting until the appearance of the disease, begins in early December and continues through mid-January or mid-February. The second period, characterized by conditions that are good to optimal for disease development, extends from the appearance of the disease through mid- or late April. The third period, during which environmental conditions are less favorable for disease development, extends from the end of April through the end of June, when the sanitation period begins.
  Spray programs should be based on the division of the season based on the appearance and development of powdery mildew. During the first period, there is no need to spray. Spray treatments should be applied at the beginning of the second period, based on observations of the situation in the field, and continually applied once every 1 to 2 weeks, depending on the level of infection and the material being sprayed. During the final period, spray treatments should be discontinued, in accordance with the low level of infection in the field at that time.

  Acknowledgements
  We would like to thank the Chief Scientist of the Ministry of Agriculture for funding this research.

  שפה English
  מלות מפתח Cucumis melo, powdery mildew, Podosphaera xanthii, walk-in tunnel, off-season agriculture
  מחבר Shimon Pivonia, Rachel Lavite, Svetlana Dobrinin, Israel Tsabari, Ela Yosel, Yigal Elad, Dan Shtainberg
  שנה 2010
  שייכות yzvieli
  תאריך יצירה 1/10/2011
  תאריך עדכון 14/3/2012
• 12

  Dec
  Development of an organic IPM regime for winter basil crops

  Vegetables, Plant Protection

  by Dafna Harari

  תחום או ענף אורגני; הגה"צ; ירקות; תבלינים

  תאריך עדכון 1/10/2011

  תיאור מלא Development of an organic IPM regime for winter basil crops

  Dafna Harari, Shimon Pivonia, Dorit Hasmonai, Rami Golan, Svetlana Gogio – Northern and Central Arava R & D
  Yigal Elad – Institute of Plant Protection, Agricultural Research Organization, Volcani Center
  David Silverman, Svetlana Dobrinin – Extension Service (Shaham), Ministry of Agriculture and Rural Development

  Email for correspondence: dafnahr@arava.co.il

  The main problem in organic herb crops is that of crop protection, how to control diseases and pests. Herbs are attacked by a number of diseases and pests. The intensity and severity of the damage caused varies from crop to crop. Herb production is characterized by a large number of harvests over the course of the season followed by renewed vegetative growth. Some of these harvests are technical harvests. The main foliar disease in most herb species is gray mold (Botrytis cinerea), which is particularly problematic during the winter and decreases the shelf-life of the harvested crop. The options for controlling Botrytis in organic crops are limited. For this reason, the specific goals of this study were to define the optimal environmental conditions for retarding the development of diseases and pests and to define the reciprocal relations between them.
  In an experiment carried out at the Yair Research Center in the Arava during the 2009-2010 growing season, we tested the effects of different growth regimes on basil crops. The tested regimes were as follows: A) control – standard plant density, ventilated building, covered beds; B) spacious – more space between plants, ventilated building, covered beds; C) closed building (warm) – standard plant density, closed building, covered beds; and D) total ground cover – standard plant density, ventilated building, continuous coverage of the soil in the beds and the paths between them. The harvests were carried out based on the size of the plants and the cropping season. The ventilated treatment in which the ground was completely covered produced the highest average yield throughout the season as well as the highest average overall yield (2.7 kg/m2), which was significantly higher than the yield in the closed, unventilated (warm) buildings (2.1 kg/m2). In the treatments in which the ground was completely covered or in which there was more space between the plants (15 plants/m2, which is two times less than the normal stand density) or in which the building was ventilated, the quality of the yield was good, index 2.5. This was in contrast to the quality of the yields in the control treatment and the warm treatment in the closed building, which received average scores of 2.3 and 2.1, respectively, indicating that the basil harvested from those plots was not marketable.
  During a relatively warm winter, there appear to be clear yield and yield-quality advantages to growing basil in ventilated buildings, in which humidity is low, as opposed to closed buildings. Similar advantages were observed for the use of a lower plant density and ventilation. Growing basil at a lower plant density did not significantly decrease yield, relative to the standard density. The quality of the basil grown at the lower density was higher than that of the basil grown at the regular density. Research aimed at identifying biological control methods for use against pathogens as well as the optimal agro-technical conditions for winter herb crops should be continued.

  Acknowledgements
  We would like to thank the Scientist’s Fund for funding Research Program no. 603-0203-09. We would also like to thank the management of the Vegetable Division of the Plant Board and the Association of Herb Growers for helping to fund this project.

  שפה English
  מלות מפתח Integrated pest managment, walk-in tunnels, Botrytis, Bemisia, whitefly, fresh-cut herbs
  מחבר Dafna Harari, Shimon Pivonia, Dorit Hasmonai, Rami Golan, Svetlana Gogio, Yigal Elad, David Silverman, Svetlana Dobrinin
  שנה 2010
  שייכות yzvieli
  תאריך יצירה 1/10/2011
  תאריך עדכון 14/3/2012
• 10

  Dec
  Establishment of the predatory mite Euseius scutalis in pepper and its potential for use in the control of broad mites

  Plant Protection, Vegetables

  by Danit Parker

  תחום או ענף אורגני; הגה"צ; ירקות

  תאריך עדכון 1/10/2011

  תיאור מלא Establishment of the predatory mite Euseius scutalis in pepper and its potential for use in the control of broad mites

  Danit Parker, Shimon Pivonia - Arava Research and Development.
  Shimon Shtainberg, Arnon Alush, Avner Hess - Bio Bee

  Email for correspondence: ShimonP@arava.co.il

  Broad mite (Polyphagotasnemus latus) is a serious pest in many agricultural crops, including pepper. From transplanting through flowering, there is no biological control agent that can be used against broad mite that can survive on the plant and, aside from sulfur, which may be used in organic crops and which requires a large-scale treatment, there is no other solution for the control of this pest. Sweet potato whitefly (Bemisia tabaci gennadius) is another agricultural pest. This insect is a serious, multi-host pest that affects a number of crops, including pepper. To date, a number of biological control agents have been tested for use against sweet potato whitefly, including the predatory mite Amblyseius swirskii, which is used as a biological control agent against thrips, sweet potato whitefly and even, to a limited extent, against red mites. This mite is a member of the Phytosediidae family, which includes many species of predatory mites, including Euseius scutalis. In contrast to the predatory mite A. swirskii, which is naturally found on the coastal plain, the E. scutalis mite is naturally found in the Arava. This is an advantage in terms of adapting this species to the local climate.
  In experiments that were carried out during the 2009/10 season at the Yair Research Station, we examined the efficacy of the predatory mite E. scutalis as a biological control agent for use against broad mite in pepper and examined its ability to establish itself from the transplanting phase through flowering with the aid of weekly applications of pollen. We also compared the abilities of the predatory mites E. scutalis and A. swirskii to control sweet potato whitefly.
  The mite E. scutalis was able to control broad mite. When this mite is distributed at transplanting in situations in which sweet potato whitefly is not already present inside the net-house or other cropping structure (as is generally the case in plots covered with 50-mesh netting), there is a concern for the diet of the predatory mite that necessitates the application of pollen, so that the mite can survive until flowering or the appearance of insects that it can eat. Weekly spraying of the plants with pollen preserves a minimal population of the predatory mite inside the cropping structure. Without these pollen sprays, the mite will disappear until flowers appear. The results of our second experiment only hint to the potential of E. scutalis as a means of controlling sweet potato whitefly.
  In the coming years, we will continue to evaluate the use of E. scutalis for the biological control of broad mite in pepper, from transplanting through flowering and onward. We will also evaluate its potential for use against sweet potato whitefly and examine the reciprocal relationship between this mite and Orius fleas. This flea may be responsible for the disappearance of this mite during the winter, as was observed in the present study.

  שפה English
  מחבר Danit Parker, Shimon Pivonia, Shimon Shtainberg, Arnon Alush, Avner Hess
  שנה 2010
  שייכות yzvieli
  תאריך יצירה 1/10/2011
  תאריך עדכון 14/3/2012