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Research

• 12

  Dec
  Using fungicides for the control of the sudden wilting of melon and watermelon caused by Monosporascus cannonballus

  Plant Protection, Vegetables

  by Shimon Pivonia, Ph.D.

  תחום או ענף הגה"צ; ירקות

  תאריך עדכון 1/10/2011

  תיאור מלא Using fungicides for the control of the sudden wilting of melon and watermelon caused by Monosporascus cannonballus

  Shimon Pivonia, Rachel Levite, Ami Maduel – Northern and Central Arava Research and Development
  Roni Cohen, Zeev Gerstel – Ne'va Ya'ar Research Center, Agricultural Research Organization, Israel

  Email for correspondence: ShimonP@arava.co.il

  Melon is the main crop in the Arava. The main soilborne disease of melon in the Arava and other regions of southern Israel is the sudden wilting caused by the fungus Monosporascus cannonballus. Today, there is still no alternative to methyl bromide for the control of this disease in melon during the spring growing season. The goals of the research conducted by Arava R&D during the 2006/7 and 2008/9 seasons were as follows: A) to study the efficacies of different fungicides for the control of Monosporascus in the Arava; and B) to study the timing and frequency of fungicide applications, as well as application rates. We evaluated the abilities of fungicides from different chemical families to delay the vegetative growth of Monosporascus in Petri dishes. In a field study conducted at the Zohar Research Station (Sodom Valley) during the fall and spring seasons, we evaluated the efficacy of these fungicides, as well as their effects on the yields of melon and dwarf watermelon. We attempted to identify the necessary application timings, application rates and frequency of application. The examination of fungicides in Petri dishes was found to be an effective approach for the primary screening of materials for use against Monosporascus. We identified a number of substances that effectively prevented the development of this disease in roots and the death of melon and dwarf watermelon plants in the field.
  The experiments described in the report facilitated the granting of licenses for the use of Amistar (azoxystrobin) and Sportak (prochloraz) to control Monosporascus in melon. The products Signum (pyraclostrobin + boscalid) and Commodore (azoxystrobin + chlorothalonil) are in a registration process. Based on the knowledge accumulated to date, recommendations have been publicized for the application of fungicides in melon and dwarf watermelon in different seasons. These recommendations have been adopted by the majority of growers in the Arava and other parts of the country and have contributed to the noticeable decrease in the death of plants in the field and increased yields. Intelligent use of fungicides, involving alternation between different substances within and between growing seasons, allows us to prevent or decrease the effects of a variety of soil-associated and canopy diseases in melon and helps preserve the long-term efficacy of these substances.

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

  שפה English
  מלות מפתח Cucumis melo, Citrullus lanatus
  מחבר Shimon Pivonia, Rachel Levite, Ami Maduel, Roni Cohen, Zeev Gerstel
  שנה 2010
  שייכות yzvieli
  תאריך יצירה 1/10/2011
  תאריך עדכון 14/3/2012
• 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
  Evaluation of substances for the control of rust mites in organic tomato crops

  Plant Protection

  by Shimon Pivonia, Ph.D.

  תחום או ענף אורגני; הגה"צ; ירקות

  תאריך עדכון 1/10/2011

  Evaluation of substances for the control of rust mites in organic tomato crops

  Shimon Pivonia, Rachel Levite, Ela Yosel – Central and Northern Arava Research and Development.

  Email for correspondence: ShimonP@arava.co.il

  Tomato is an important crop for organic agriculture in the Arava. For the 2009-2010 growing season, a total of 750 dunams of organic tomato were planted in the Arava, accounting for 30% of the total organic acreage and 50% of the tomato acreage in the Arava. During a tour of the fields of a number of organic growers during the 2008-2009 season, we saw many fields that were heavily infested with tomato rust mite (Aculops lycopersici). This mite causes bronzing of leaves and stems, causes leaves to dry out and causes fruit to turn yellow and turn corky. In an experiment carried out in the organic section of the Yair Research Station in the Arava during the 2009/10 season, we examined the control efficacies of three materials that may be used in organic crops: sulfur dust, EOS oil and Genikan. These treatments were compared with an untreated control. There were two replicates of each treatment. On September 1, 2009, tomato plants cv. Misty were transplanted into15-m-long walk-in tunnels that were covered with 50-mesh netting. The plants were grown on trellises, as is customary.
  The spontaneous, expected infestation of the crop with rust mite began in late October. During November and December, we applied each of the spray treatments four times (two weeks between each treatment). No treatments were applied in January and, for the rest of the season, we sprayed as necessary based on scouting of the crop. From February until April, we applied Genikan an additional six times in one replicate and four in the other. During this period, we applied EOS an additional five times in one replicate and three in the other and we made one additional application of sulfur in one of the replicates for that treatment. The incidence of mites reached 100% in the control plants by the end of January and in the Genikan-treated plants by March. In the EOS and sulfur treatments, the incidence of damaged plants remained low throughout the season and reached 30-50% by the end of April. In terms of plant damage, intense drying-out of the crop canopy was observed in the control plots, as well as fruit damage. However, the level of damage observed in the control plots was lower than that observed in the Genikan-treated plots. The plants treated with sulfur or EOS oil remained vibrant through the end of the study and no damage was observed in the fruit from these treatments. The sulfur dust treatment was the most effective for controlling rust mites. The EOS oil treatment provided the next-best mite control, but required more applications than the sulfur treatment. Genikan was not sufficiently effective to prevent the damage caused by this mite.

  Acknowledgements
  We would like to thank the Makhteshim and Da Kedem companies for supplying the spray products for this study and Katrina Krizova for the photographs.

  שפה English
  מחבר Shimon Pivonia, Rachel Levite, Ela Yosel
  שנה 2010
  שייכות yzvieli
  תאריך יצירה 1/10/2011
  תאריך עדכון 14/3/2012