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• 9

  Jan
  Summer basil without Bemisia tabaci – Zohar Research Station 2009/10

  Plant Protection, Vegetables

  by Murad Ghanim, Prof.

  25 Summer basil without Bemisia tabaci Zohar Research Station 2009/10

  תחום או ענף הגה"צ; ירקות; תבלינים

  תאריך עדכון 1/10/2011

  Summer basil without Bemisia tabaci – Zohar Research Station 2009/10

  Murad Ghanim – Institute of Plant Protection, Volcani Center, Agricultural Research Organization
  Dafna Harari, Ami Maduel, Danit Parker, Uri Zairi – Central and Northern Arava R & D
  David Silverman, Svetlana Dobrinin – Extension Service, Ministry of Agriculture and Rural Development
  Iris Ben-David – Ein Tamar

  Email for correspondence: ghanim@volcani.agri.gov.il

  The whitefly Bemisia tabaci is a cosmopolitan pest with many hosts; it can develop on hundreds of plant species. This whitefly transmits viruses that cause damage in a number of crops. In herb crops, the main problem is that this pest is a quarantine pest that is unwanted in the countries to which these crops are generally exported. In herb crops such as basil, the damage caused by this pest is particularly serious because the whitefly is based in the parts of the plants that are not harvested. In recent years, an increase in the appearance of this whitefly and a decrease in the efficacy of some of the control measures used against it have been reported. This change is due to selection pressure on the whitefly populations. Most of the sprays used put selective pressure on the subspecies Q, which is known to be associated with the development of resistance to many classes of chemicals.
  The goal of the experiment that was carried out during the summer of 2010 was to evaluate different treatments, including greenhouse-type structures and sprays, in an effort to keep plants free of this whitefly for long periods of time. The experiment, which was carried out at the Yair Research Station in Sodom Valley, included four treatments and three replicates of each treatment. Each replicate was a polyethylene tunnel covered with shade netting. The ventilation openings and double entranceway of each tunnel were covered with insect netting. All of the tunnels were connected to a hallway with 50-mesh netting that had a dark, double entranceway. Basil cv. Pri was transplanted on May 7, 2010. The treatments included an unsprayed control, preventative sprays and reactive sprays based on scouting every two weeks in tunnels covered with regular polyethylene and UV-blocking polyethylene.
  Our scouting observations indicate that there is an advantage to using UV-blocking polyethylene and this advantage was clear in the reactive treatments with and without UV-blocking polyethylene. The preventative treatment was effective in that it kept the pest populations low and this type of treatment is preferred over a reactive treatment, in which the crop is treated after the first pests have been discovered. It appears that the initial resistance status of the populations that enter the building determines the level of the populations that will develop because, in this case when resistant populations are present, the efficacy of the spray treatments is doubtful. If the population that enters the building is made up of subspecies Q, we need to test for resistance if we want to only apply effective treatments. Otherwise, we may see the rapid development of populations that are not susceptible to spray treatments.

  Acknowledgements
  We would like to thank the Chief Scientist’s Fund of the Ministry of Agriculture of funding this research program as part of the Herb Initiative. We would also like to thank the management of the Vegetable Division of the Plant Board and the Herb Growers Association for helping to fund this experiment. We thank herb growers Eran Wein and Yoram Ozeri from Ein Tamar and the AdaFresh Company for their cooperation and for storing and transporting the basil for the shelf-life evaluation.

  שפה English
  מלות מפתח resistance, plant protection, insecticide, management
  מחבר Murad Ghanim, Dafna Harari, Ami Maduel, Danit Parker, Uri Zairi, David Silverman, Svetlana Dobrinin, Iris Ben-David
  שנה 2010
  שייכות yzvieli
  תאריך יצירה 1/10/2011
  תאריך עדכון 14/3/2012
• 17

  Dec
  Winter collapse of pepper 2007/8

  Plant Protection, Vegetables

  by Shimon Pivonia, Ph.D.

  תאריך עדכון 14/1/2009

  תיאור מלא The phenomenon of winter collapse of pepper (Capsicum annuum L.), the wilting of mature plants from December through February, has been known in the Arava for many years. Over the years, the use of methyl bromide as a soil fumigant kept the phenomenon at negligible levels. Winter collapse of pepper appeared on a wider scale during the 2004/5 and 2006/7 growing seasons. The phenomenon is seen primarily in the cooler areas of the Arava, in Paran and Tzofar and, to a lesser extent, in Ein Yahav.
  In experiments that were conducted in controlled growth chambers at the Yair Research Station during the 2007/8 growing season, pepper plants were infected with pythium isolated from wilted plants. The plants were grown at average temperatures of 25, 14, 10.5 and 8.6ºC. At temperatures of 14 and 25ºC, no damage was observed on the infected plants, as compared with control plants. In contrast, at 8.6ºC, we observed the death of many plants, beginning two weeks after the infection date. At 10.5ºC, many plants were damaged, but not completely killed. This damage was not seen until many weeks after the inoculation date. The pythium isolate used in this study was sent to a laboratory abroad for identification. It was identified as a new species of Pythium, previously unknown to science. The results of this study provide a good explanation of the relationship between the appearance of the disease, the type of structure used in the cropping system (i.e., net-house or greenhouse) and environmental conditions. In the last decade, relatively high levels of collapse were observed in the 1999/2000, 2004/5 and 2006/7 growing seasons. In each of these seasons, temperatures during December and January were below average for extended periods of time. The move from net-houses to greenhouses in areas that have suffered from winter collapse in previous years has led to a noticeable decrease in the level of collapse. Measurements of soil temperature collected last season in greenhouses and net-houses explain this phenomenon. In areas with similar climates, minimal soil temperatures in greenhouses are higher than those in net-houses.

  שפה English
  מלות מפתח Capsicum
  מחבר Shimon Pivonia, Rachel Levite, Eviatar Etiel
  שנה 2008
  שייכות yzvieli
  תאריך יצירה 14/1/2009
  תאריך עדכון 14/3/2012

  OPEN
• 17

  Dec
  Amblyseius swirskii PEPPER 2006-7

  Plant Protection

  by Carmit Tal

  תאריך עדכון 10/5/2008

  תיאור מלא So far, no biological means against the broad mite (Polyphagotarsonemus latus) could be provided by natural enemies and its eradication was performed using chemicals or sulfur containing pesticides. In a study conducted during the 2006/7 season in Yair Station in the Arava Valley, the feasibility of using the predatory mite A. swirskii against the broad mite was investigated in sweet pepper (Capsicum annuum) grown in walk-in tunnels. In addition, the effects of this predator on the population of the western flower thrips (F. occidentalis) and on the severity of damage to the fruit were evaluated. The predatory mite performed a high level of broad mite eradication, equal to that of chemicals, when applied at a population of 100 individuals/m2 two weeks after planting in a plot that had been naturally infested by high levels of whitefly and broad mites. Also, the predatory mite lessened the level of the thrips population, particularly on the autumn and the early winter. A reduction in the damage caused by thrips to the pepper fruit was observed as well. Later on, however, with the decline of the predatory mite population during the winter, and along with the rise in the thrips population then, the damage to the fruit increased again. It appears that A. swirskii may be used as an auxiliary tool, complementary to Orius insidiosus for the reduction of the thrips level in the field, but it should not be considered as the sole solution.

  שפה English
  מחבר Carmit Tal, Phyllis Weintraub, Sophia Kleitman ,Shimon Pivonia, Yael Bar-Lavan ,Shimon Steinberg
  שנה 2008
  שייכות yzvieli
  תאריך יצירה 10/5/2008
  תאריך עדכון 14/3/2012

  OPEN